SAIN Invasive Plant Pests Resource Collection for: Common Reed
Species (scientific name): Phragmites australis
| Title: Germination response of Phragmites australis and Typha latifolia to diurnal fluctuations in temperature. |
| Author: Ekstam-Borje ; Forseby-Asa. |
| Source: Seed-Science-Research. June, 1999; 9 (2): 157-163. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Germination responses to 45 combinations of diurnal mean temperature and amplitude were examined in freshly collected seeds of two wetland perennials: Typha latifolia L. and Phragmites australis (Cav.) Trin. ex Steudel. Nearly all seeds (> 95%) germinated in favourable temperature regimes. Mean temperature (range 10-30degreeC) and amplitude (range 0-20degreeC) affected final germination of both species. P. australis required a high amplitude (> 10degreeC) for germination over the entire range of mean temperatures. Final germination of T. latifolia was more sensitive to mean temperature than P. australis. The germinated proportion of T. latifolia had a maximum around 20degreeC, above which it decreased, and amplitudes were more stimulating at low than at high levels of mean temperature. The germination rate was rapid and increased with mean temperature for both species. More than 50% germination was achieved within 1-3 d at favourable temperatures. It is proposed that the thermal requirements provide the non-dormant seeds with a season-sensing mechanism which postpones germination of seeds dispersed during autumn, winter or early spring, until the soil surface is heated by the sun in the spring and sufficiently large diurnal fluctuations of temperature occur. Furthermore, the amplitude requirement implies a strong avoidance mechanism for germination of P. australis in sites with small temperature fluctuations (e.g. below water tables), whereas seeds of T. latifolia appear to be less exacting in the requirements when the soil or water becomes warmer. |
| Title: Activity of phase I and phase II detoxication enzymes in different cormus parts of Phragmites australis. |
| Author: Plfugmacher-Stephan ; Geissler-Katja; Steinberg-Christian. |
| Source: Ecotoxicology-and-Environmental-Safety. Jan., 1999; 42 (1) 62-66. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Enzymes of phase I and phase II of the xenobiotic detoxication pathway (ethoxyresorufin-O-deethylase, peroxidases, microsomal and soluble glutathione-S-transferases) were measured in roots, stems, and leaves of Phragmites australis, revealing different enzyme activities in these parts. Highest enzyme activities were measured in the root followed by the leaf. Enzyme activities detected in the stem were low compared with those in the root and leaf. The high detoxication capacity of the root and the leaf might be due to very high exposure to xenobiotics and to the high levels of metabolism in these cormus parts. The function of the stem of Phragmites is mainly transportation, so a high detoxication level is not useful, as indicated by the low enzyme activities. |
| Title: Phragmites australis: Effects of shoot submergence on seedling growth and survival and radial oxygen loss from roots. |
| Author: Armstrong-Jean ; Afreen-Zobayed-Fawzia; Blyth-Sarah; Armstrong-William. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 275-289. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Laboratory experiments indicated that any degree of permanent submergence +40-+120 mm) of young seedling shoots of Phragmites (height: 20-30 mm) greatly reduced (75-100%) the chances of their becoming emergent. With +40 mm submergence and with an absence of algae, about 25% of shoots emerged and grew normally; where algal growth developed during the experiment, 15% of shoots emerged, but where the submerging water was particularly rich in P and algae were present from the onset, no shoots emerged. Seedling leaves which became covered in epiphytic algae lost their chlorophyll. The roots of submerged plants tended to develop more extensive aerenchyma than those of controls whose shoots were emergent. When, after 25 days, water tables were lowered to the soil surface in sand treatments, seedlings recovered quickly except for those from a treatment with dense algal growth. In more mature seedlings (shoot height = 300-400 mm) gradual submergence of shoots in either light or darkness reduced radial oxygen loss (ROL) from adventitious root apices. At 23degreeC there was no ROL at complete submergence in darkness; at 18degreeC the values were from 7-23% of the dark, fully emergent condition. When the lights were switched on, ROL increased almost immediately due to photosynthetic oxygen generation and entrapment in the submerged shoots. At 18degreeC the values attained, relative to the dark emergent condition, were from 42-59%, but at 23degreeC they were much lower: 13-26%. These effects are discussed in relation to the regeneration of Phragmites by the establishment of seedlings, possibly after die-back. |
| Title: Organic acids in the sediments of wetlands dominated by Phragmites australis: Evidence of phytotoxic concentrations. |
| Author: Cizkova-Hana ; Brix-Hans; Kopecky-Jiri; Lukavska-Jaroslava. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 303-315. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Spatial and seasonal variations in concentrations of lower organic acids in the sediments of stands of Phragmites australis (Cav.) Trin. ex Steud. were studied in wetlands in the Czech Republic (Rozmberk fishpond), Hungary (Lake Ferto and Kis-Balaton), and Denmark (Vejlerne Nature Reserve). Pore water concentrations of lactic, formic, acetic, propionic, butyric, oxalic, citric, tartaric, malic and fumaric acid were analysed by HPLC and shown to vary both qualitatively and quantitatively between sites. Acetic acid was prevalent at all sites, and dominated together with citric, malic, and tartaric acid at Rozmberk fishpond, with lactic and oxalic acid at Lake Ferto and Kis-Balaton, and with lactic and propionic acid at Vejlerne Nature Reserve. The maximum total concentrations of organic acids recorded were 2984 and 2215 mumol l-1 at a land and a deep-water site of Rozmberk fishpond, 1673 and 2216 mumol l-1 at a healthy and damaged stand of Lake Ferto, 1006 and 1642 mumol l-1 at ahealthy and damaged stand of Kis-Balaton, and 570 and 223 mumol l-1 at a healthy reed stand and a lagoon at Vejlerne Nature Reserve, respectively. At Rozmberk fishpond the concentrations of lower organic acids were considered sufficiently high to diminish the plants vigour and possibly to induce die-back. At Lake Ferto and Kis-Balaton the organic acids are unlikely to have had a toxic effect on the reeds at the sampling time because of the relatively high pH (apprx7) in these wetlands. However, because of the great spatial and seasonal variability in organic acid speciation and concentration, organic acid phytotoxity may affect the reed also at these sites. At Vejlerne Nature Reserve, the toxic effect on the reeds is unlikely because of consistently low concentrations of organic acids. |
| Title: Nitrogen and carbohydrate storage in rhizomes of Phragmites australis (CAV.) TRIN. ex STEUDEL at different aquatic sites of lakes in Upper Bavaria. |
| Author: Pohl-Wolfgang; Grosser-Stephan; Melzer-Arnulf. |
| Source: Limnologica-. Jan., 1999; 29 (1) 36-46. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Nitrogen and carbohydrate utilization in Phragmites australis rhizomes was investigated under natural conditions at 10 sites in 5 lakes in Upper Bavaria over a period of two years. Nitrate and ammonium of surface and interstitial water was determined. The results indicate that conditions of habitat and environment, such as climate and fluctuation of water level, lead to different adaptations of reed. These parameters had an effect on the storage of nitrogen and carbohydrate. The reed stands exposed to high water level during spring and summer have a high carbohydrate content in the rhizomes. A positive correlation was shown between the aboveground biomass and the content of storaged carbohydrates during the vegetation period. No relationship could be demonstrated between the nitrogen availability of the habitats and the type of storage of carbohydrates and nitrogen. The nitrogen content in the rhizomes can be used as an indicator of the ability of reed stands to produce new secondary shoots after shoot loss. The differently established reed genotypes are not able to compensate short-term environmental changes, such as growing leisure problems and higher shoot loss by the increasing appearance of waterfowl, from their reserve storage. |
| Title: Phenotypic differences among ploidy levels of Phragmites australis growing in Romania. |
| Author: Pauca-Comanescu-Mihaela ; Clevering-Olga-A; Hanganu-Jenica; Gridin-Mihai. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 223-234. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: This paper presents data showing phenotypic differences of Phragmites australis (Cav.) Trin. ex Steud. (Common reed) growing in Comana lake and in the Danube Delta (Romania). In Comana lake, tetra- and octoploids were found, whereas in the Danube Delta also hexaploids occurred. In freshwater habitats, shoots of octoploids were longer and thicker with more nodes than those of tetraploids. Panicles of octopoids were also larger than those of tetraploids. The number of alive leaves did not differ between ploidy levels. Total leaf area, however was higher of octo- than of tetraploids, which indicates that octoploids produced larger leaves. Octoploids also had thicker rhizomes. No differences in allocation of dry matter to leaves, stems, and leaves (blades and sheaths) were found between tetra- and octoploids. Both tetra- and octoploids shoots were among the tallest in the central Danube Delta. Tetraploids were morphologically more diverse in Comana lake than in the central Danube Delta.Within areas, size of shoots could, however, not be related to water depth. Salinity reduced shoot size of tetraploids considerably. Under saline conditions, no differences in morphology of shoots were found between tetra- and hexaploids. |
| Title: Isozyme variation among populations of the clonal species, Phragmites australis (Cav.) Trin. ex Steudel. |
| Author: Pellegrin-Dana; Hauber-Donald-P. |
| Source: Aquatic-Botany. April, 1999; 63 (3-4) 241-259. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Few studies have examined population genetic variation in clonal, emergent, aquatic plant species. Phragmites australis (Cav.) Trin. ex Steudel is a clonal, cosmopolitan species common to marshes, estuarine, and other wetland habitats. With the exception of several European studies examining local variation, little is known about the distribution of genetic variation in this taxon, particularly in the U.S. In recent years, the rapid and invasive, vegetative spread of P. australis into disturbed marsh habitats in the U.S., particularly on the Eastern Seaboard and the Mississippi River delta, has sparked interest in its ecology and genetic structure. In this study, electrophoresis was used to analyze isozyme variation among 37 populations of P. australis from the eastern half of the U.S. The electrophoresis data strongly support a primarily vegetative mode of reproduction and spread. A total of 21 multilocus, isozymic phenotypes were identified among the 37 populations. All populations sampled along the Gulf Coast (GC) from Texas to the Florida panhandle (with the exception of the two populations from the Mississippi River delta) were uniform, sharing a single, multilocus phenotype. P. australis populations had lower levels of percent polymorphic loci and number of alleles per locus than typical asexual terrestrial species, but had a higher mean heterozygosity. Nei's genetic distance UPGMA depicts a substantial amount of geographic clustering of populations. However, populations described as 'invasive' showed no genetic similarity to one another. |
| Title: Iron oxidation states on root surfaces of a wetland plant (Phragmites australis). |
| Author: Wang-Tiangen ; Peverly-John-H. |
| Source: Soil-Science-Society-of-America-Journal. Jan.-Feb., 1999; 63 (1) 247-252. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Iron in root plaque is usually thought to be Fe(III) because of rhizosphere oxidation. This study was conducted to examine Fe oxidation states on root surfaces of the common reed (Phragmites australis (Cav.) Trin. ex Steudel). Using an EDTA-BPDS method, Fe(II) and Fe(III) on the surfaces of roots sampled from various environments were stabilized, extracted and determined simultaneously. The proportion of extracted Fe(II) to total Fe ranged from 0.17 to 0.65 for the roots grown in constructed wetlands, fields, and hydroponic culture; and from 0.34 to 0.70 for different sections of wetland plant roots. The observed results suggested that Fe plaque is caused not only by rhizosphere oxidation, but also by Fe(II) compound formation on the root surfaces. |
| Title: Interactive effects of N and P on growth, nutrient allocation and NH4 uptake kinetics by Phragmites australis. |
| Author: Romero-Jose-Antonio; Brix-Hans; Comin-Francisco-A. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 369-380. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: The interactive effects of three levels of NH4-N (50, 500 and 1000 mumol l-1) and two levels of phosphate (15 and 50 mumol l-1) on growth, nutrient allocation and ammonium uptake kinetics by Phragmites australis (Cav.) Trin. ex Steudel were studied in hydroponic culture in the laboratory. Nitrogen level in the root solution significantly affected the relative growth rate of the plants, the rate being lower at low N (0.026 per day) than at intermediate (0.035 per day) and high N (0.037 per day), but phosphorus did not significantly affect growth. The N : P ratio in the root solution significantly affected the growth rate which was highest at N : P ratios between 10 and 33 on a molar basis. Nitrogen and phosphorus concentration in the plant tissues generally increased with N level in the root solution, but P level had no effect. Plant tissue N : P ratios (on a molar basis) varied between 13.5 in the stems to 28.0 in the leaves and were unaffected by the treatments. Ammonium uptakekinetics were unaffected by N treatment, but Vmax was significantly affected by P treatment averaging (mean +- 95% confidence limits (CL)) 151 +- 44 mumol g-1 root dry weight h-1 in the low-P treatment and 229 +- 70 mumol g-1 root dry weight h-1 in the high-P treatment. The overall mean (+-95% CL) NH4-N uptake kinetic parameters were: Vmax = 190 +- 20 mumol g-1 root dry weight h-1; K1/2 = 21.8 +- 1.8 mumol l-1, and Cmin = 1.2 +- 0.2 mumol l-1. Mean (+-SD) root respiration rate was 72 +- 22 mumol CO2 g-1 dry weight h-1 and was unaffected by the treatments. The results of the study support the general hypothesis that P. australis is well-adapted for growth in nutrient-rich habitats. However, P. australis is able to acclimate to low nutrient availability by increasing the affinity for ammonium uptake. |
| Title: Interactive effects of N and P on growth, nutrient allocation and NH sub(4) uptake kinetics by Phragmites australis. |
| Author: Romero,-J.A.; Brix,-H.; Comin,-F.A. |
| Source: Aquatic-Botany [Aquat.-Bot.] 1999 vol. 64, no. 3-4, pp. 369-380. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Special Issue: Genetic diversity, ecophysiology and growth dynamics of the common reed (Phragmites australis). The interactive effects of three levels of NH sub(4)-N (50, 500 and 1000 mu mol l super(-1)) and two levels of phosphate (15 and 50 mu mol l super(-1)) on growth, nutrient allocation and ammonium uptake kinetics by Phragmites australis (Cav.) Trin. ex Steudel were studied in hydroponic culture in the laboratory. Nitrogen level in the root solution significantly affected the relative growth rate of the plants, the rate being lower at low N (0.026 per day) than at intermediate (0.035 per day) and high N (0.037 per day), but phosphorus did not significantly affect growth. The N:P ratio in the root solution significantly affected the growth rate which was highest at N:P ratios between 10 and 33 on a molar basis. Nitrogen and phosphorus concentration in the plant tissues generally increased with N level in the root solution, but P level had no effect. Plant tissue N:P ratios (on a molar basis) varied between 13.5 in the stems to 28.0 in the leaves and were unaffected by the treatments. Ammonium uptake kinetics were unaffected by N treatment, but V sub(max) was significantly affected by P treatment averaging (mean plus or minus 95% confidence limits (CL)) 151 plus or minus 44 mu mol g super(-1) root dry weight h super(-1) in the low-P treatment and 229 plus or minus 70 mu mol g super(-1) root dry weight h super(-1) in the high-P treatment. The overall mean ( plus or minus 95% CL) NH sub(4)-N uptake kinetic parameters were: V sub(max) = 190 plus or minus 20 mu mol g super(-1) root dry weight h super(-1); K sub( one half ) = 21.8 plus or minus 1.8 mu mol l super(-1), and C sub(min) = 1.2 plus or minus 0.2 mu mol l super(-1). Mean ( plus or minus SD) root respiration rate was 72 plus or minus 22 mu mol CO sub(2) g super(-1) dry weight h super(-1) and was unaffected by the treatments. The results of the study support the general hypothesis that P. australis is well-adapted for growth in nutrient-rich habitats. However, P. australis is able to acclimate to low nutrient availability by increasing the affinity for ammonium uptake. |
| Title: Insects on common reed (Phragmites australis): Community structure and the impact of herbivory on shoot growth. |
| Author: Tscharntke-Teja. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 399-410. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: In this paper, community structure of endophagous insects attacking common reed (Phragmites australis (Cav.) Trin ex Steud.) and impact of herbivory on shoot growth was analyzed in south west Germany. All the 26 phytophagous insects were monophagous, i.e. restricted to their host plant P. australis, which appeared to be due to the predictability and apparency of the large and ancient Phragmites stands. Habitat types were clearly separated due to the mean shoot diameter ('dry' and 'wet' reed) and the mean level of shoot damage (high and low abundance of Archanara shoots). The stem-boring moth Archanara geminipuncta greatly influenced structure of the insect community, due to heavy shoot damage, and could be classified to be the key species of the reed ecosystem. In contrast to common expectations of negative effects, Archanara shoot damage enhanced populations of many insect species, so insect guilds of 'primary attackers' (on the main shoot) and 'secondary attackers' (on damaged shoots) could be separated. Primary attackers either killed the growing point or attacked the apical, medium or basal internodes, while secondary attackers were facilitated by shoot damage and could also be subdivided in four guilds: Inquilinous species living between the wilting leaves of damaged shoots, attackers of the side shoot growing in response to the destruction of apical meristems, saprophagous species feeding on Archanara droppings, and the successor community of bees and wasps nesting in empty galls or broken shoots. There is a continuum from evident plant damage, e.g. by stem-boring moths and leaf-sucking aphids, to enhanced shoot growth due to the parasitic influence of gall makers, e.g. the significant shoot elongation by the gall midge Giraudiella inclusa. In Europe, conservationists are concerned about the die-back of P. australis, while in North America and Australia, P. australis is considered to be an invasive weed. Classical biological control with the introduction of European insects (like the moth A. geminipuncta) is discussed. |
| Title: Analysis of genetic diversity among selected populations of Phragmites australis world-wide. |
| Author: Koppitz-Heike. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 209-221. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Genetic diversity among reed (Phragmites australis) populations from 70 sites in Europe and from 12 sites in other continents was determined using the random amplified polymorphic DNA (RAPD) technique. Based on results from about 1000 reed samples screened with different primers, both polyclonal reed stands, where different clones co-exist either next to each other or intermingle, and monoclonal reed stands were found. Generally a higher diversity of clones was detected from sites on or near shore than in the water. Cluster analysis of genetic similarity coefficients from 30 to 80% demonstrated a high degree of genetic diversity among reed stands world-wide. Lower genetic diversity was detected among samples from any location, with coefficients ranging from 70 to 100%. In general, the genetic distances of investigated reed samples within Europe increase with increasing geographic distances. The reed samples from the other continents formed a separate major cluster in the phenogram. |
| Title: Distribution of the aphid Hyalopterus pruni GEOFFR. within and between habitats of common reed Phragmites australis (CAV.) TRIN. ex STEUDEL as a result of migration and population growth. |
| Author: Mook-Jaap-H ; Wiegers-Jaap. |
| Source: Limnologica-. Jan., 1999; 29 (1) 64-70. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: The aphid Hyalopterus pruni migrates to its secondary host Common Reed in late spring and early summer. Reed fields are known to be more heavily infested at the edges compared to the centre, as the migrants are attracted to the colour of the reed. There is also evidence that reeds growing at wet sites are more heavily infested than at dry sites. This paper shows that both processes interact in determining the distribution of aphids in different habitats. The observations were carried out in the vast reed field of the Zuidelijk Flevoland polder (The Netherlands) during a number of years after its reclamation in 1968. In the period of migration flying aphids were caught with sticky traps situated in and around the reed field. The distribution of aphids on the reed was determined at different times during the season along transects through the centre of the polder. The existence early in the season (June) of a higher infestation at the edges than in the centre of the field was confirmed. The density of winged aphids in this early period was higher in wet than in dry habitats, which may have been a result of a preference of the settling migrants for reed standing in water. Later in the season (August) the dry habitat still had a relatively low infestation in the centre, but at the wet sites the infestation was high everywhere. This could be attributed to the much quicker population growth that was found in the wet habitat and subsequent short range movement of newly born winged aphids. |
| Title: Distribution of the invasive reed Phragmites australis relative to sediment depth in a created wetland. |
| Author: Pyke-Christopher-R ; Havens-Kirk-J. |
| Source: Wetlands-. March, 1999; 19 (1): 283-287. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: This study collected new data on sediment thickness and distribution and integrated it with existing data on the distribution of plant species within a small (0.5 ha) created, tidal salt marsh in Langley, Virginia, USA. The presence of the reed Phragmites australis was found to be inversely correlated with sediment accumulation on the marsh surface. Sediment-deficient areas seem at a higher risk for invasion by P. australis and subsequent loss of designed marsh habitat. The results indicate that areas of low sediment accumulation may be used as a proxy measure for areas vulnerable to invasion. These areas can be easily delimited both in the field and on aerial photography. |
| Title: Responses of ecotypes of Phragmites australis to increased seawater influence: A field study in the Danube Delta, Romania. |
| Author: Hanganu-Jenica ; Mihail-Gridin; Coops-Hugo. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 351-358. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: The effects of locally increased salinity in a complex of Fine and Giant reed (Phragmites australis) clones were investigated in the Tataru channel (Danube Delta, Romania). Following digging of the Tataru channel, the area closest to the sea became isolated from freshwater input, causing saline conditions to develop due to its proximity to the sea. The other side of the channel remained a freshwater area. The impact of increased salinity on the regression of reed was studied and related to a possible difference in susceptibility to high salt concentrations between different clones (Octoploid Giant reed versus Tetraploid Fine reed). Measurements were made in survey plots situated on both sides of the channel. In freshwater, Giant reed had higher and thicker shoots than Fine reed, but stem density was much smaller, resulting in a lower biomass per surface area of Giant reed. Growth of both Giant and Fine reed was severely reduced at the saline east side of the channel. A significant interaction was found between reed type and salinity. Giant reed density, height, stem diameter and biomass were more strongly affected by saline conditions than Fine reed. The salinization of the parts east of the channel might thus have affected Giant reed stands more strongly than Fine reed stands. The implications for reed succession under increased salinity in the delta are discussed. |
| Title: Bank protection using common reed (Phragmites australis). |
| Author: Coops-Hugo. |
| Source: Levende-Natuur. Feb., 1999; 100 (2): 46-49. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Wave action is an important factor in the degradation of reedbelts. This can be due to both an indirect impact, such as the sorting of sediments in the shore zone, and to a direct impact, i.e. bending and breaking of stems and washing out of plants. Among other parameters, strength and flexibility of individual stems determine the erosion susceptibility of a reed stand. Measures taken to prevent damage to reed stands often target on excluding wave action by any sort of protective construction, or for instance limitation of speed for passing boats. There are still many questions to be answered to provide a clear view on the restoration potential of littoral reed stands, concerning: 1) the strength of reed stands to withstand erosion and other environmental impacts, 2) the application of different ecotypes of reed, and 3) the effects of water-level alterations on reed performance. |
| Title: Clone specific differences in a Phragmites australis stand I. Morphology, genetics and site description. |
| Author: Kuehl-Harald ; Koppitz-Heike; Rolletschek-Hardy; Kohl-Johannes-Guenter. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 235-246. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: A selected reed stand (Phragmites australis) at a shallow lake near Berlin was investigated from 1992 to 1995. This reed stand is clearly divided into four visually distinguishable clusters. The study focuses on the clonal distribution within the whole reed stand in relation to morphological characteristics. Furthermore, it should be proved if the clustered stand structure is caused by different site conditions. Genotypic variability was detected by using the RAPD-technique. The parameters shoot length, leaf area, number of internodes and leaves, diameter of culms, shoot density and percentages of shoots with panicles were measured once a year at the end of the vegetation period. The concentrations of ammonium, nitrate, nitrite, o-phosphate and sulphate in interstitial water and sediment extracts were determined. Four adjacent clones were found, which showed differences in morphology. These differences in shoot architecture were observed in spite of uniform site conditions. This suggests a large clonal difference in expression of morphological features. First conclusions are drawn regarding the relationship between genotypes within a reed stand and the expression of morphological characteristics. |
| Title: Clone specific differences in a Phragmites australis stand II. Seasonal development of morphological and physiological characteristics at the natural site and after transplantation. |
| Author: Rolletschek-Hardy ; Rolletschek-Alexandra; Kuehl-Harald; Kohl-Johannes-Guenter. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 247-260. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Two Phragmites clones, growing adjacent to each other but differing conspicuously in stand structure, were investigated in 1996 regarding seasonal change in morphological and physiological parameters. Both clones showed significant differences in shoot morphology (length, diameter, dry weight, leaf area), maximum above-ground (420 versus 152 g DW m-2) and below-ground biomass (2.4 versus 1.5 kg DW m-2). Furthermore, physiological parameters (N concentration, N and P content per shoot and m2, content of dissolved amino acids, N translocation rate) varied between clones in their time course. Clone-specific variations in these characteristics were significant even after transplantation to another field site. Overall, these results suggest that the distinct growth forms and levels of productivity of the two Phragmites clones are the result of genotypic variation. It is hypothesized that both clones follow distinct ecophysiological strategies causing their morphotypic differentiation. Implications of genotypic determination of growth forms are discussed in relation to nutrient supply, N limitation, population plasticity, eutrophication and reed regression. |
| Title: Controls on soil cellulose decomposition along a salinity gradient in a Phragmites australis wetland in Denmark. |
| Author: Mendelssohn-Irving-A ; Sorrell-Brian-K; Brix-Hans; Schierup-Hans-Henrik; Lorenzen-Bent; Maltby-Edward. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 381-398. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Although soil organic matter decomposition is an important process determining nutrient transformations and availability in wetland ecosystems, few studies have attempted to assess which environmental factors are most important in controlling spatial differences in decomposition rates found along environmental gradients. Relative soil decomposition was determined in a Phragmites australis Cav. Trin ex Steudel dominated wetland in northern Jutland, Denmark along a natural salinity gradient, where nutrients, soil moisture, temperature and salinity among other factors also varied. Our objective was to identify which edaphic factors most limited rates of relative soil decomposition, as evaluated by measuring cellulose decomposition with the cotton strip technique. Replicate cotton strips were placed at seven marsh sites along the salinity gradient, and soil and interstitial water samples were collected and analyzed for major macro- and micronutrients (NH4-N, NO3-N, P, PO4, K, Mg, Ca,Na, S, Fe, Mn, Zn, Cu, Mo, B, Si), pH, Eh, conductivity, temperature, and soluble sulfides. Cellulose decomposition, expressed as cotton tensile strength loss (CTSL) per day, decreased with increasing salinity, except at the highest salinity site where a significant increase occurred. Mean CTSL values, averaged for each marsh site, varied 3-fold from 1.8 to 5.5% loss per day. Principal component and multiple regression analyses were used to prioritize the importance of the various factors that might control this spatial difference in CTSL rates. Although soil conductivity (salinity) accounted for the large percentage (45%) of the variation in the environmental data, soil fertility- and soil reduction-associated variables explained the greatest percentage (56%) of the spatial variation in cellulose decomposition. Univariate correlation analyses supported the conclusion that soil fertility, primarily inorganic nitrogen and phosphorus, is the major environmental factor determining soil cellulose decomposition rates along this salinity gradient. |
| Title: Carbohydrate storage in rhizomes of Phragmites australis: The effects of altitude and rhizome age. |
| Author: Klimes-Leos ; Klimesova-Jitka; Cizkova-Hana. |
| Source: Aquatic-Botany. June, 1999; 64 (2): 105-110. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Starch, glucose, fructose and sucrose were measured in nodes and internodes of horizontal rhizomes of Phragmites australis in two localities, at 400 and 1350 m above sea level respectively, before spring growth started. In the respective localities, five and four age categories of rhizomes were distinguished. Rhizomes of lowland plants, harvested on March 21, contained more starch (17.6%), glucose (2.5%) and total non-structural carbohydrates (35.2%) per gram dry mass than rhizomes of plants collected at the tree line on June 3 (11.8, 1.7 and 30.5%, repectively). The proportion of water soluble carbohydrates to total non-structural carbohydrates, as an indication of acclimatisation to a cold climate, was higher in the mountain locality (60 and 49%, respectively). Glucose and starch concentrations increased with rhizome age in both localities. All other carbohydrate fractions were independent of locality. Water soluble carbohydrates were preferentially accumulated in internodes whereas starch was accumulated in nodes. |
| Title: Carbohydrate and nutrient content in rhizomes of Phragmites australis from different habitats of Lake Ferto/Neusiedlersee. |
| Author: Dinka-Maria ; Szeglet-Peter. |
| Source: Limnologica-. Jan., 1999; 29 (1) 47-59. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Changes in the soluble sugar, starch, total non-structural carbohydrate (TNC) and nutrient (N, P, K) concentration in the reed rhizome were investigated in different reed habitat types in Lake Ferto/Neusiedlersee during the vegetation period in 1993 to 94. Three die-back and four vigorous reed stands were monitored. For biomass estimations rhizomes were collected twice. in early summer and in autumn. They were calculated to be 1.9 to 2.7 kg/m2 at die-back and 3.1 to 6.1 kg/m2 at vigorous sites. The carbohydrate and nutrient concentrations of the reed rhizomes were high at the beginning of the vegetation period; they reached their minima in May-June, which was followed by a gradual increase until the end of the vegetation period. From autumn to spring the concentrations decreased, e.g. TNC concentration by 15 to 40% at vigorous, 50 to 70% at die-back sites. In both years the lowest carbohydrate concentrations were recorded at the end of May, a month before the inflorescence developed (vigorous sites: 50-70 mg TNC/g, die-back sites: 70-120 mg TNC/g). In that period the standing stock of the TNC in the rhizome did not separate the sites clearly, and the smallest carbohydrate standing stock was measured at a vigorous site with a high water cover. At the beginning of summer and in autumn the soluble sugar, TNC and N concentration values were higher at the die-back than at the vigorous sites but the standing stock was higher at the vigorous sites. In autumn the TNC standing stock of the rhizomes was between 780 and 1200 g/m2 at vigorous, between 380 and 690 g/m2 at die-back sites. This is especially important for the reactions and resistance of die-back reed stands to unfavourable conditions. |
| Title: Growth and photosynthetic performance of Phragmites australis in estuarine waters: A field and experimental evaluation. |
| Author: Adams-J-B ; Bate-G-C. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 359-367. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Surveys of South African estuaries showed that in estuaries that had a gradient of decreasing salinity up the length of the estuary salt marshes occurred near the saline middle-lower reaches and reeds and sedges in the brackish upper reaches. However, in certain estuaries common reed Phragmites australis occurred in the lower reaches of estuaries. The plants often extend into the intertidal zone where they are inundated with saline water (35 ppt). This study tested whether P. australis occurred at these sites because its roots were located in fresh or brackish water. In P. australis stands in the Goukou and Keurbooms estuaries interstitial water salinity was lower than surface water salinity. There was an increase in interstitial salinity towards the water's edge and this was associated with a decrease in the height of P. australis. Laboratory studies tested whether P. australis could survive tidal inundation with saline water (35 ppt) if its roots and rhizomes were located in freshwater (0 ppt). Plants which were supplied with freshwater to the roots but were tidally inundated with saline water had greater stem elongation and less dead leaves than plants that were supplied with 20 ppt salinity to the roots. P. australis will probably only survive intertidal flushing with saltwater if its roots and rhizomes are located in brackish water (<20 ppt). This accounts for the presence of P. australis in saline estuaries at the sites of freshwater seepage. |
| Title: Does the common reed, Phragmites australis, affect essential fish habitat? |
| Author: Weinstein-Michael-P ; Balletto-John-H. |
| Source: Estuaries-. Sept., 1999; 22 (3B): 793-802. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Since the early 1900s Phragmites australis has been replacing other vegetation in Atlantic and Gulf coast marshes at a rate of about 1% to 6% of the marsh surface per year. Vast areas of coastal marsh are now characterized by dense monotypic stands of this species. By virtue of its ability to build up the marsh surface, P. australis affects the landscape, hydrology, and hydroperiod of the marsh as well as drainage density, and other geomorphic features. Smoothed microtopography results in more difficult access to the marsh by nekton, and possibly reduced exchange of organic materials between the marsh and adjacent estuary. The pattern of replacement by P. australis results in fragmentation of existing stands of Spartina alterniflora and other extant macrophytes, thereby altering landscape ecology and the ability of the marsh to support biodiversity and the production of marsh fauna. |
| Title: Taxonomy, chromosome numbers, clonal diversity and population dynamics of Phragmites australis. |
| Author: Clevering-Olga-A ; Lissner-Jorgen. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 185-208. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Phragmites australis (Cav.) Trin. ex Steud. (common reed) is one of the most widespread plant species in the world. The species has a high phenotypic variation in morphology and life-history traits. This high phenotypic variation can be related to variance in chromosome numbers, clonal diversity, plasticity of clones or a combination of these. An overview of our present, still limited, knowledge concerning the amounts, causes and maintenance of genetic diversity in P. australis is given. In P. australis a large range in euploid number has been found (between 3x-12x, except for 5x and 9x, with x = 12). In Europe tetraploids are dominant, whereas octoploids predominate in Asia. Aneuploids also occur regularly in P. australis, and differences in chromosome numbers have been observed even within clones. Clonal diversity in P. australis has been studied using allozyme polymorphisms and molecular markers. Both mono- and polyclonal stands are known to exist. A surprisingly high number of clones has been found in European stands. Environmental and genetic factors, which may account for this high clonal diversity, are discussed. In most studies on the occurrence of ecotypes in P. australis no distinction has been made between plastic and genetic variation. But evidence exists that responses to climate, hydrology and salt have a genetic basis. Until now no attempts have been made to determine which genes or gene complexes are responsible for these different responses. |
| Title: Ecological and molecularbiological investigations on reed (Phragmites australis (CAV.) TRIN. ex STEUDEL) in lakes of Northern Germany - An overview. |
| Author: Schieferstein-Barbara-B. |
| Source: Limnologica-. Jan., 1999; 29 (1) 28-35. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: The structure, function and dynamics of reed-belts from three 'Bornhoeved-Lakes' was investigated by using methods from vegetation science and molecular biology. Between 1992 and 1994 the morphometry and production of Phragmites was measured at twelve locations, differing in sedimentology and hydrochemistry. The development and production of the plants, as well as the nutrient uptake and relocation, were similar throughout the years within each of the twelve plots. Differences in stand-structure and amounts of nutrients occurred between the habitats. Nitrogen content in the plant material varied between 5 and 30 g N m-2 and phosphorus between 0.3 and 1.2 g PO4-P m-2. 80 natural reed habitats were measured for Restriction Fragment Length Polymorphisms (RFLPs) in order to identify the genetic diversity of Phragmites within the lakes. A cluster analysis exhibited groups with high, as well as groups with low genetic similarity. Even if genetically similar, the habitats were not necessarily directly neighboured at the shoreline. A discriminance analysis showed 40% correspondence of the genetic groups with their phenotype and habitat parameters. |
| Title: Effect of climate on the salt tolerance of two Phragmites australis populations. I. Growth, inorganic solutes, nitrogen relations and osmoregulation. |
| Author: Lissner-Jorgen ; Schierup-Hans-Henrik; Comin-Francisco-A; Astorga-Val. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 317-333. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: This study estimated the effects of Danish (temperate nemoral) and Spanish (mediterranean) climatic conditions on the salt tolerance of two Phragmites australis (Cav.) Trin. ex Steud. populations. Plants propagated from seeds collected in Denmark (=Danish population) and Spain (=Spanish population) were exposed to salinity levels ranging from 0 to 30permill at outdoor experimental plots situated in Denmark (56degreeN) and Spain (41degreeN). Plants were measured for growth rate, mortality, below-ground/above-ground ratio, water content, ash content, nitrogen content, C:N and ions (K+, Na+, Mg2+, Ca2+, Cl-). Growth was significantly enhanced at the Spanish growth site, especially for salinity levels ranging from 10 to 20permill. In this interval, growth rates of both the Danish and the Spanish population were 20-100% higher than at the Danish growth site. These growth data point to higher salt tolerance at the Spanish site when using relative salt tolerance and absolute salt tolerance as criteria. Salt tolerance is ascribed to two important mechanisms, cation adjustment and water loss. Despite higher transpiration at the Spanish site, plants were able to maintain or improve K+/Na+ ratios of leaf laminas, indicating enhanced cation adjustment under the Spanish climatic conditions. Primarily, this was due to higher K+ accumulation at the Spanish site (305-378 mmol kg-1) as compared to the Danish site (220-268 mmol kg-1), while a climatic effect on Na+ level only was evident for the Danish population. Climatically induced differences in water content may also have contributed significantly to the higher salt tolerance observed for plants at the Spanish site. Shoot water content was lower at the Spanish site (1.9-2.4 g water g-1 DW) than at the Danish site (2.6-4.0 g water g-1 DW), suggesting that water loss is an important mechanism contributing to osmotic adjustment. Water loss may act by concentrating solutes in the cell sap, thereby reducing the need for synthesis of metabolically expensive organic osmotica as well as reducing the need for Na+ uptake for osmotic adjustment. This study also showed that P. australis populations differ in salt tolerance. A relatively higher salt tolerance observed for the Danish population was related to lower mortality, lower leaf Na+ and Cl- content, higher leaf K+/Na+ ratio, higher leaf nitrogen content, higher below-ground/above-ground ratio and lower ash content of below-ground parts and is discussed in relation to partitioning. |
| Title: Effect of climate on the salt tolerance of two Phragmites australis populations. II. Diurnal CO sub(2) exchange and transpiration. |
| Author: Lissner,-J.; Schierup,-H.-H.; Comin,-F.A.; Astorga,-V. |
| Source: Aquatic-Botany [Aquat.-Bot.] 1999 vol. 64, no. 3-4, pp. 335-350. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Special Issue: Genetic diversity, ecophysiology and growth dynamics of the common reed (Phragmites australis). This study examined the effects of salinity and climate on instantaneous CO sub(2) exchange rates and daily carbon balance for two populations of Phragmites australis. Plants propagated from seeds collected in Denmark (=Danish population) and Spain (=Spanish population) were grown at salinities of 0, 5 and 10% at outdoor experimental plots situated at a nemoral growth site (Denmark, 56 degree N) and at a mediterranean growth site (Spain, 41 degree N). In situ measurements of shoot CO sub(2) exchange were made under different meteorological conditions. Maximum CO sub(2) uptake rates were 24 and 19 mu mol m super(-2) s super(-1) in Spain and Denmark, respectively, and were only reached under conditions of full sunlight. On sunny days, CO sub(2) uptake was reduced less by salinity at the Spanish site than at the Danish site. Photosynthetic photon flux densities saturating shoot photosynthesis were much lower in Spain (ca. 600 mu mol m super(-2) s super(-1)) as compared to those in Denmark (ca. 1300 mu mol m super(-2) s super(-1)). This affected the period of maximum CO sub(2) uptake rates which was 2-3 h longer at the Spanish growth site, despite shorter day length at this site (15 h) than at the Danish site (17 h). |
| Title: Expansion of Phragmites australis into tidal wetlands of North America. |
| Author: Chambers-Randolph-M ; Meyerson-Laura-A; Saltonstall-Kristin. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 261-273. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Phragmites expansion into tidal wetlands of North America is most extensive along the northern and middle Atlantic coasts, but over 80% of the US coastal wetland area occurs along the Gulf of Mexico and southern Atlantic coasts and may be susceptible to ongoing expansion. Rapid spread of Phragmites has been documented in freshwater (<0.5 ppt), oligohaline (0.5-5 ppt) and mesohaline (5-18 ppt) tidal wetlands. The advance of Phragmites into tidal wetlands of North America may have been facilitated by widespread coastal changes since European settlement, including disturbance of hydrologic cycles and nutrient regimes; the presence of Phragmites has become a signature of tidal wetland alteration. Although ploidy levels from 2n = 36 to 72 have been documented for Phragmites throughout the continent, no genetics research to date has tested whether recent introduction of aggressive clones could account for Phragmites expansion. A fundamental concern regarding Phragmites expansion, particularly into tidal freshwater wetlands, is the observed reduction in biodiversity as many native species of plants are replaced by a more cosmopolitan species. Commensurate with a shift in habitat type is a reduction in insect, avian and other animal assemblages. Ecosystem services, including support of higher trophic levels, enhancement of water quality and sediment stabilization, however, are not diminished when a tidal wetland becomes dominated by Phragmites, provided that tidal flooding is retained. |
| Title: Genetic diversity, ecophysiology and growth dynamics of reed (Phragmites australis). |
| Author: Brix,-H. |
| Source: Aquatic-Botany [Aquat.-Bot.] 1999 vol. 64, no. 3-4, pp. 179-184. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Special Issue: Genetic diversity, ecophysiology and growth dynamics of the common reed (Phragmites australis). The common reed, Phragmites australis (Cav.) Trin ex Steudel, is among the most widespread and productive plant species in the world, and is one of the few species that can truly be regarded as cosmopolitan. It is a robust, perennial emergent aquatic plant up to 6 m high, belonging to the family Poaceae. The annual stems develop from a system of vertical and horizontal perennial rhizomes that also function in the vegetative spread of the plant. P. australis usually forms dense, nearly monospecific stands in littoral zones of lakes, along rivers and irrigation/drainage canals and in shallow, freshwater swamps. Its geographical distribution extends from cold temperate regions to the tropics. Some of the largest Phragmites-dominated ecosystems in the world are found in Europe (e.g., the Danube Delta and Lake Ferto), where the stems of the reeds have been used for centuries for roofing and fencing. Phragmites also plays an important role in preventing wave and current erosion of river and lake banks, and in providing a habitat for wild fowl and other fauna. Many bird reservations are wetlands in which P. australis is the dominant species. These areas have a great economic value for tourism (bird watching and hunting) and often support fisheries of local importance. It is, therefore, not surprising that P. australis is one of the most extensively studied wetland species in the world. |
| Title: Methanogenesis and methane emissions: Effects of water table, substrate type and presence of Phragmites australis. |
| Author: Grunfeld-Simon; Brix-Hans. |
| Source: Aquatic-Botany. May, 1999; 64 (1): 63-75. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Effects on methanogenesis and CH4 emission of three water table positions, sediment composition and presence or absence of the emergent macrophyte Phragmites australis (Cav.) Trin. Ex Steud. were studied in outdoor experimental mescosms. Water table position significantly affected methanogenesis and CH4 emission, the rates being 40% and 60% lower, respectively, in vegetated organic sediments with a water table 22 cm below the surface as compared with vegetated inundated sediments. Due to the high water-holding capacity of organic sediments, rates of methanogenesis and CH4 emission in organic sediments with a water table 8 cm below the sediment surface were only slightly, but not statistically significantly different from rates in inundated sediments. Sandy sediments with water tables 8 cm below the sediment surface had very low methanogenic activity as compared with organic sediments (1 versus 55 mmol m-2 per day). The presence of P. australis in inundated sediments attenuatedthe rate of methanogenesis by 27%, enhanced the proportion of CH4 oxidised from 7% to 118%, and as a result attenuated CH4 emission by 34%. In vegetated sediments CH4 emission peaked at midday and was longest during the night and early morning in concert with the diurnal changes in internal convective flow in the plants. Internal gas transport through the plants accounted for 62% of the CH4 emitted from vegetated sediments while ebullition dominated in unvegetated sediment. |
| Title: Biometric variation in Phragmites australis affecting convective ventilation and amino acid metabolism. |
| Author: Rolletschek-Hardy ; Hartzendorf-Thomas; Rolletschek-Alexandra; Kohl-Johannes-Guenter. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 291-302. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Parameters of convective ventilation and amino acid patterns in basal culm internodes of Phragmites australis (Cav.) Trin. ex Steud. were studied at four sites in the Danube Delta (Romania) in May 1997. The considerable stand-specific differences in shoot diameter, length and density were related to ventilation efficiency. Tall shoots with high diameters were able to induce higher gas flow rates per generated pressure differential, than those with smaller diameters. However, if the flow rates of single culms were related to the corresponding shoot densities, stands with thinner shoots but higher densities achieved significantly higher ventilation efficiencies per m2 reed stand. These differences in the rate at which rhizomes can be flushed with air were reflected in amino acid patterns in basal culm internodes. The fractions of Ala, Ser and gamma-aminobutyric acid of total amino acid content were significantly increased at stands with tall, thick shoots but low densities. The contentsof these amino acids were correlated with parameters of convective ventilation, and may indicate hypoxic conditions in basal and below-ground plant parts of P. australis. In conclusion, biometric parameters of reed stands can be decisive for determining the efficiency of convective ventilation. |
| Title: Copper- and iron-induced injuries in roots and rhizomes of reed (Phragmites australis). |
| Author: Mook-Jaap-H ; Wiegers-Jaap. |
| Source: Limnologica-. Jan., 1999; 29 (1) 60-63. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: About 1 mg/g dw Cu2+ and 8 mg/g dw Fe2+ were found in roots of reed plants when fed with heavy metal concentrations of 100 muM Cu2+ and 10 mM Fe2+ under hypoxia. Roots seemed to act as a kind of filter since the amounts in rhizomes were only 0.06 mg Cu2+/g dw and 2 mg Fe2+/g dw. Increased contents of both ions reduced posthypoxic respiration capacity by 40-50% and also the sum of adenylates (ATP, ADP, AMP) by the same order of magnitude, although energy charge values remained above 0.85 in Cu2+ and 0.79 in Fe2+ treatments. Energy metabolism of rhizomes was not affected. Copper and iron contents of roots as well as of rhizomes were high enough to induce oxidative stress when roots were fed with 40 muM Cu2+ and 1 mM Fe2+, respectively. From our results we conclude that increased, but environmentally attainable, amounts of copper and reduced iron ions disturb root energy metabolism, and therefore root functioning and development. Latent injuries, based on oxidative stress, may be harmful for roots and rhizomes under long term exposure. |
| Title: Seed production of Menyanthes trifoliata inside and outside a Phragmites australis canopy. |
| Author: Haraguchi-Akira. |
| Source: Journal-of-the-Faculty-of-Agriculture-Hokkaido-University. Feb., 1999; 69 (1): 27-30. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Reproduction of Menyanthes trifoliata L. was compared inside and outside a Phragmites australis (Cav.) Trin. ex. Steud. canopy in a floating peat mat in Mizorogaike Pond, Central Japan. Different factors influenced the reproductive organs of M. trifoliata during the seed production process inside and outside the P. australis canopy. M. trifoliata inside the canopy produced a low number of flower buds, but the inflorescences showed a higher survival rate than at the open site, hence inflorescence density per unit area did not differ significantly. However, both the seed setting ratio and the total number of seeds produced were much lower within the Phragmites site. |
| Title: Surface energy fluxes of Phragmites australis in a prairie wetland. |
| Author: Burba-G-G; Verma-S-B ; Kim-J. |
| Source: Agricultural-and-Forest-Meteorology. April 1, 1999; 94 (1): 31-51. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Components of the surface energy balance were measured in three communities (Phragmites australis, Scirpus acutus, and open water) in a wetland located in northcentral Nebraska, USA, during the growing season of 1994. This paper includes results from the area covered by Phragmites australis (reedgrass). The Bowen ratio - energy balance method was used to calculate sensible and latent heat fluxes. During daytime, with a water depth of about 0.5 m, the heat storage term (G) consumed 20-30% of the net radiation (Rn). At night, G was a significant source of energy (on average, about - 40 W m-2). The magnitude of the daily (24 h) averaged G was small. Evapotranspiration (ET) was a major consumer of the incoming solar energy. During early and peak growth, the daily ET ranged between 2.5 and 6.5 mm per day. During senescence, evapotranspiration was between 0.5 and 3.1 mm per day. ET was partitioned into transpiration (Ev) and evaporation (Es) using a dual-source modification of the Penman-Monteith equation. Results indicated that transpiration contributed 40-45% of the total ET in the beginning of the early growth stage. During the second half of the early growth stage and the entire peak growth stage, it contributed 53-62% of ET. The contribution decreased to 50% in the beginning of senescence, and to near zero in late senescence. The daytime variation of Es did not follow Rn, and seemed to be controlled by thermal stability and air dryness. Before senescence, the ratio of the actual to equilibrium evapotranspiration (ET/ETeq) averaged 1.3. It decreased to about 0.5 during senescence. The McNaughton and Spriggs (1989, IAHS Publ. 177, 86-101) model, developed primarily for dryland vegetation, significantly overestimated the ET/ETeq ratio in Phragmites when the canopy stomatal resistance was larger than 150 s m-1. The model prediction improved significantly when the contribution of evaporation was eliminated by substituting the ET/ETeq ratio by Ev/Eveq (transpiration/equilibrium transpiration). |
| Title: Effect of climate on the salt tolerance of two Phragmites australis populations. II. Diurnal CO2 exchange and transpiration. |
| Author: Lissner-Jorgen ; Schierup-Hans-Henrik; Comin-Francisco-A; Astorga-Valeria. |
| Source: Aquatic-Botany. Sept., 1999; 64 (3-4): 335-350. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: This study examined the effects of salinity and climate on instantaneous CO2 exchange rates and daily carbon balance for two populations of Phragmites australis. Plants propagated from seeds collected in Denmark (=Danish population) and Spain (=Spanish population) were grown at salinities of 0, 5 and 10% at outdoor experimental plots situated at a nemoral growth site (Denmark, 56degreeN) and at a mediterranean growth site (Spain, 41degreeN). In situ measurements of shoot CO2 exchange were made under different meteorological conditions. Maximum CO2 uptake rates were 24 and 19 mumol m-2 s-1 in Spain and Denmark, respectively, and were only reached under conditions of full sunlight. On sunny days, CO2 uptake was reduced less by salinity at the Spanish site than at the Danish site. Photosynthetic photon flux densities saturating shoot photosynthesis were much lower in Spain (ca. 600 mumol m-2 s-1) as compared to those in Denmark (ca. 1300 mumol m-2 s-1). This affected the periodof maximum CO2 uptake rates which was 2-3 h longer at the Spanish growth site, despite shorter day length at this site (15 h) than at the Danish site (17 h). Dark respiration rates of shoots were higher at the Spanish growth site (2-8 mumol CO2 m-2 s-1) as compared to the Danish site (less than 2 mumol CO2 m-2 s-1). Salinity was observed to accelerate rates of dark respiration only at the Spanish site. Integrals of shoot CO2 exchange rates over a 24 h period indicated lower total daily carbon gain at the Danish site, which under clear sky conditions was 65-80% of that at the Spanish site. Cloud cover was found to reduce net photosynthetic CO2 uptake considerably and could even cause a net loss of carbon during periods, which in absence of clouds could confer maximum uptake rates. The salt tolerance and productivity of P. australis is therefore strongly related to the ratio of realised to potential sun hours. This ratio may override the importance of other environmental factors such as temperature. This study also evaluated the effects of moderate salinity stress (0-15% salinity) on in situ P. australis transpiration. Daily transpiration rates were 30-75% higher at the Spanish site (0.38-0.56 g H2O cm-2 day-1) as compared to the Danish site (0.22-0.38 g H2O cm-2 day-1). Rates were equally affected by salinity at both the growth sites. Since water loss is an important factor behind P. australis salt tolerance it is speculated that salt tolerance may increase under conditions favouring high transpiration, contrary to most other halophytes. |
| Title: Rhizome age structure of three populations of Phragmites australis (Cav.) Trin. ex Steud.: Biomass and mineral nutrient concentrations. |
| Author: Cizkova-Hana ; Lukavska-Jaroslava. |
| Source: Folia-Geobotanica. 1999; 34 (2): 209-220. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: The rhizome age structure for populations of Phragmites australis (Cav.) Trin. ex Steud. was determined at three sites of the Trebon Biosphere Reserve (Czech Republic). These sites were classified according to plant species composition and phosphorus availability as oligotrophic (Branna), mesotrophic (Rozmberk East) and hypertrophic (Rozmberk West). P. australis stands at these sites were expanding, stabilized and retreating, respectively. Rhizomes were sampled within the terrestrial parts of the reed stands (at a water depth of about 10 cm). The rhizomes were dated according to the position in the branching hierarchy and to supplementary morphological criteria. The analysis of the branching pattern revealed that at the sites studied, the rhizomes typically branch only once a year. The longest life span of rhizomes (six years) was found for the stable reed population at Rozmberk East. The reduced rhizome life span at Rozmberk West (four to five years), accompanied by a reduced branching frequency of horizontal rhizomes, was ascribed to a greater incidence of anaerobic conditions associated with the permanent flooding of the hypertrophic organic soil. The maximum life span of the Branna population (four years) probably corresponds to the total age of the reed population. The concentrations of nitrogen, phosphorus, and potassium in the tissue decreased with rhizome age while those of calcium and magnesium increased. The effect of rhizome age on mineral-nutrient concentrations was more pronounced than the effect of site on these concentrations. The mineral nutrient concentrations were not closely associated with reed performance. |
| Title: The effects of litter on growth and plasticity of Phragmites australis clones originating from infertile, fertile or eutrophicated habitats. |
| Author: Clevering-Olga-A. |
| Source: Aquatic-Botany. May, 1999; 64 (1): 35-50. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: In many European countries a strong decline of Phragmites australis (Cav.) Trin. Ex Steudel (common reed) has been observed. In some instances this decline has been related to the accumulation of litter. A greenhouse experiment was conducted with P. australis cuttings from different stable and die-back populations in the Czech Republic and the Netherlands, which were grown in sand (oxidised substrate) and a mixture of sand and litter (reduced substrate). The stable populations were from fertile and infertile habitats, and the die-back populations from orginally infertile and now eutrophicated habitats. It was hypothesised that (i) clones from stable populations in fertile habitats are better adapted to accumulated litter (reduced substrate) than those in infertile habitats, and (ii) clones from dieback populations in eutrophicated habitats are more similar to those from stable populations in infertile than fertile habitats, and (iii) the allocation and morphological traits inducedin the different environments are adaptive i.e. result in a higher total dry weight (as a measure of fitness) in a particular environment. No significant population X substrate type interaction terms were present, therefore, populations did not differ in their responses to accumulated litter. Population differences in total dry weight, allocation and morphological traits could not be related to adaptations to accumulated litter. Therefore, the different hypotheses were rejected. Generally, clones from infertile habitats were more similar and less plastic than those from the fertile and eutrophicated habitats. Some of these latter clones had a significantly higher total dry weight in sand, but others in sand-litter. Although substrate-type had no overall effect on total dry weight, it affected almost all other plant traits. Clones growing in sand-litter had a higher dry matter allocation to leaves, leaf weight ratio, specific leaf weight ratio, and number of shoots than plants growingin sand, whereas the allocation of dry matter to stems and roots, shoot length and the distance between shoots was lower for clones growing in sand-litter than in sand. Between substrate-types no differences in dry matter of rhizomes were present, however, clones growing in sand-litter produced longer, but thinner rhizomes than those in sand. It was concluded that responses of P. australis to accumulated litter were directed towards a high input of oxygen into a small volume of substrate. It was concluded that a low dry matter allocation to roots, short shoots and a small distance between primary shoots seem to be stress reactions rather than adaptive responses in sand-litter. In contrast, a high number of especially primary shoots seems to be adaptive in this substrate. |
| Title: Study on the salinity-adaptation physiology in different ecotypes of Phragmites australis in the Yellow River Delta of China: Osmotica and their contribution to the osmotic adjustment. |
| Author: Zhao-K-F ; Feng-L-T; Zhang-S-Q. |
| Source: Estuarine-Coastal-and-Shelf-Science. Aug., 1999; 49 (SUPPL. A): 37-42. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: In the Yellow River Delta, there are four ecotypes of Phragmites australis: freshwater swamp reed; salty-water swamp reed; lower salt-meadow reed and higher salt-meadow reed. The growth status, composition and dominance of the reed community were observed. The organic and inorganic osmotica, osmotic potential and osmotic adjustment ability of reeds were determined. The abundance, coverage, plant height, leaf water content and osmotic potential all decreased with increasing salinity of habitats. K+ and sugars are the main osmotica in lower salinity, while Na+ is the main osmoticum in higher salinity. Na+ contents and the osmotic adjustment abilities of roots are higher than those in leaves. Na/K ratios of reeds varied with salinity levels of habitats, being about 1 in higher salinity. Moreover, the contributions of osmotica to the osmotic adjustment change with salinity, the higher the salinity level, the greater the contribution of inorganic osmotica, but the smaller the contribution of organic osmotica. |
| Title: The macrofungi and decay of roofs thatched with water reed, Phragmites australis. |
| Author: Anthony,-P.A. |
| Source: Mycological-Research [Mycol.-Res.] 1999 vol. 103, no. 10, pp. 1346-1352. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: This study examined the occurrence or macrofungi and the decay of roofs thatched with water reed, Phragmites australis. Sampling from 20 north- and 20 south-facing roof sides showed that several ascomycetes usually associated with reed in situ are common on thatch. The only basidiomycetes recorded were Mycena species. There was no significant difference in the representation of macrofungi on north- and south-facing roof sides, but Mycena spp. only produced basidiomes on surfaces facing north, suggesting that the dry environment of the south side prevents fruiting. Eleven species were recorded in total, and the average of 2 times 4 species per roof did not increase with the age of thatch or degree of decay. The same species were generally present on young and old thatch, and no successional stages of fungal communities could be distinguished with increasing roof age. Deterioration of thatch occurs at the exposed surface of the roof and progresses inwards. Within the layer of reeds outer, middle, and inner zones develop representing different stages in the decay. The zones move inwards as thatch deteriorates. A comparison of the rate of decay among roofs with pitch 30 degree , 45 degree and 60 degree showed that the innermost zone appeared ca 20 cm from the exposed reed butts in both of the steeper roofs, whereas it was no longer present in the roof with low pitch. This suggests that the depth of the zones depends upon the roof slope, and the outer and middle zones move inwards at a higher rate in roofs with a low pitch, resulting in an increased rate of deterioration. Phragmites thatch appears to harbour its own characteristic macrofungal community, with certain Mycena species likely to represent the principal decomposers. A common feature of fungi occurring on thatch is that they must endure unfavourable conditions. |
| Title: A comparative study of surface energy fluxes of three communities (Phragmites australis, Scirpus acutus, and open water) in a prairie wetland ecosystem. |
| Author: Burba-George-G ; Verma-Shashi-B ; Kim-Joon. |
| Source: Wetlands-. June, 1999; 19 (2): 451-457. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Components of the surface energy balance were measured using the Bowen ratio-energy balance method in three different communities (Phragmites australis, Scirpus acutus, and open water) in a wetland located in north-central Nebraska during the growing season of 1994. During daytime, the heat storage term (S) was a considerably larger sink of energy in open water as compared to the vegetated communities (Phragmites and Scirpus). During nighttime, S was a significant source of energy in all three communities. As compared to the evapotranspiration (ET) from Phragmites and Scirpus, the evaporation (E) from open water (averaged over the measurement period) was about 25% smaller during daytime and three times larger during the night. The diurnal pattern of ET in Phragmites and Scirpus generally followed that of Rn. The diurnal pattern of the open water E, however, did not follow Rn; rather, it seemed to depend on thermal stability conditions and air dryness. For the overall measurement period, the daily integrated (24-hour) evaporation from the open water area was 8% more than the evapotranspiration from the Phragmites-dominated part of the wetland and 17% more than the evapotranspiration from the Scirpus-dominated part of the wetland. |
| Title: The effect of light and number of diurnal temperature fluctuations on germination of Phragmites australis. |
| Author: Ekstam-B ; Johannesson-R; Milberg-P. |
| Source: Seed-Science-Research. June, 1999; 9 (2): 165-170. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Seed germination of the wetland emergent perennial Phragmites australis is stimulated by diurnally fluctuating temperatures. A germination experiment in darkness and light at different temperature regimes showed that P. australis germinated as well in darkness as in light over most of the temperature regimes tested. The germination requirements could partly explain why this species, despite a large annual production of small seeds, does not accumulate a persistent soil seed bank. A second experiment examined the effect of one to four diurnal temperature cycles with amplitude of fluctuations ranging from 0 to 30degreeC; diurnal mean temperature of 15degreeC. Germination in the absence of fluctuations was low, and logistic model estimates showed a positive effect of number of temperature cycles which was strongly influenced by amplitude size. For seeds that have fallen on moist ground during the winter, these laboratory results predict that a few large diurnal temperature fluctuations couldbe sufficient for onset of germination in the subsequently warmer spring period. Seeds that are located under water, however, are predicted to remain ungerminated until the water level falls. Hence, we suggest that the requirement for fluctuating temperature, in addition to being a sensor for 'exposed' seed sites, is also effectively acting as a germination timing mechanism. |
| Title: Habitat factors related to the invasion of reeds (Phragmites australis) into wet meadows of the Swiss Midlands. |
| Author: Brulisauer-Alfred ; Klotzli-Frank. |
| Source: Zeitschrift-fuer-Oekologie-und-Naturschutz. Dec., 1998; 7 (3) 125-136. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Habitat factors related to the invasion of reeds into Molinia coerulea-dominated wet meadows and small-sedge communities were investigated by transect analysis. The abundance of Phragmites was found to be strongly related to increased levels of soil nitrogen and phosphates. A competitive advantage of Phragmites over other species of wet meadows at increased nutrient levels may result from an improved capacity to cope with unbalanced nutrient situations, such as high levels of nitrogen but low levels of potassium. |
| Title: Implications of missing efflux sites on convective ventilation and amino acid metabolism in Phragmites australis. |
| Author: Rolletschek-H ; Bumiller-A; Henze-R; Kohn-J-G. |
| Source: New-Phytologist. Oct., 1998; 140 (2) 211-217. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Three stands of Phragmites australis (Cav.) Trin. ex Steudel were investigated regarding the relationship between the number of efflux culms and convective ventilation efficiency affecting the hypoxic status of roots and rhizomes. The lack of old (efflux) culms after mowing the preceding winter caused a significantly higher counterpressure within the rhizome, thereby diminishing air flushing rate, i.e. oxygen supply, of rhizomes. The levels of alanine and gamma-aminobutyric acid in basal culm internodes increased significantly. Both amino acids indicate the hypoxic status of the root and rhizome metabolism of P. australis. Amino acid patterns of the basal culm internodes are discussed with respect to the maintenance of aerobic root metabolism and nutrient availability. |
| Title: Comparison of biomass and metal uptake between two populations of Phragmites Australis grown in flooded and dry conditions. |
| Author: Ye-Z-H; Wong-M-H; Baker-A-J-M ; Willis-A-J. |
| Source: Annals-of-Botany-London. July, 1998; 82 (1) 83-87. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: The biomass and metal concentrations of two populations of Phragmites australis were studied by growth in a glasshouse in three ameliorated substrata (Mai Po (MP) sediment, fly ash (FA) and lead/zinc mine tailings (TL)) under flooded and dry conditions for 90 d. Plants were raised from seeds from 'clean' (Mai Po, Hong Kong) and metal-contaminated (Plombieres, Belgium) sites. Seedling growth was best in fly ash, root dry weights being higher in flooded than dry conditions, and growth poorest in tailings, in which shoot and root dry weights were higher under dry conditions for both populations. However, in the MP substratum conditions did not significantly affect shoot and root dry weights of either population. In the fly ash aid tailings, more metals were generally taken up in both roots and shoots in flooded than dry conditions, but there was little difference in the MP substratum. Metal uptake was mostly similar in both populations in seedlings grown in the same substratum, there being no clear evidence of ecotypic differentiation. |
| Title: An investigation into the effects of nitrogen on growth and morphology of stable and die-back populations of Phragmites australis. |
| Author: Clevering-Olga-A. |
| Source: Aquatic-Botany. Jan., 1998; 60 (1) 11-25. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: In many European countries a strong decline of Phragmites australis (common reed) populations has been observed during the past two decades. This has become known as die-back or reed regression. A greenhouse growth experiment was performed with P. australis cuttings from stable and die-back populations from The Czech Republic and The Netherlands. The stable populations were from fertile and infertile environments, and the die-back populations were originally from infertile but now eutrophicated habitats. It was hypothesised that (i) stable P. australis populations from fertile and infertile habitats would show inherent differences in biomass (allocation) and N-content in response to nitrogen loading, and (ii) die-back populations would be more similar to stable populations from infertile as opposed to fertile habitats in terms of biomass (allocation) and N-content. The stable Czech populations showed an increase in dry weight with increasing fertility of the habitat. This was not related, however, to leaf area ratio (LAR), specific leaf area (SLA) or nitrogen use efficiency (NUE). The dry weight of the stable Dutch populations did not vary with fertility, although the population from the infertile habitat showed a higher allocation of dry watter and nitrogen to the below-ground parts as compared to the fertile habitat population. Total dry weight of the die-back Czech population did not differ from that seen for stable populations from the infertile habitats, and no differences were found between the Dutch populations. Die-back populations did not show a higher resemblance with stable populations from infertile as opposed to fertile habitats with respect to plant traits involved in the capture of light and/or nitrogen. Most plant traits were affected by nitrogen, irrespective of habitat fertility, and populations did differ in morphology and dry matter allocation. However, since performance of populations could not he related to the fertility of the habitat, both hypotheses were rejected. The importance of other selectional processes is discussed. |
| Title: Morphological and histochemical analysis of galls of Lipara lucens (Diptera, Chloropidae) on Phragmites australis (Poaceae). |
| Author: Vandevyvere-Inez ; De-Bruyn-Luc. |
| Source: Canadian-Journal-of-Botany. Aug., 1998; 76 (8) 1374-1384. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Lipara lucens Meigen (Diptera, Chloropidae) is a monophagous herbivore of the common reed. Phragmites australis Cav. (Trin.) ex Steud. (Poaceae), on which it induces typical cigar-shaped galls. In this paper, the anatomy and histochemistry of galls, cultivated in a greenhouse and collected in the field. were examined. Gall growth takes place while the larva feeds outside the actual developing gall. During gall growth, internode elongation is reduced. Internally, the pith parenchyma, destined to become the nutritive tissue, proliferates instead of degenerating as is seen in uninfested stems. The tissue cylinder around the gall chamber widens up to three times its normal size, while the pith parenchyma doubles its width. The central pith of nutritive cells becomes surrounded by an inner layer of longitudinal and an outer layer of radial parenchymatous cells. Vascular strands, likely connected to the vascular tissue of the host plant, run through this special band of parenchyma cells. The bundles are oriented perpendicular to the stem axis, surrounding the larval chamber. When the gall is completed, the larva gnaws through the growing point and enters the gall chamber, where it consumes the nutritive tissue. A sclerenchymatization process starts now resulting in an extremely hardened gall. Histochemical staining reveals the presence of proteins, DNA, RNA, and a gradient of lipid globules in the nutritive tissue. No starch was detected. |
| Title: Abundance of common reed (Phragmites australis), site conditions and conservation value of fen meadows in Switzerland. |
| Author: Guesewell-Sabine; Kloetzli-Frank. |
| Source: Acta-Botanica-Neerlandica. March, 1998; 47 (1) 113-129. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: The abundance of Phragmites australis (Trin.) has increased in many fen meadows of the Swiss Plateau. The vegetation of 241 4-m2 plots was surveyed to determine how the abundance of Phragmites australis was related to site conditions and to the botanical conservation value. The aboveground biomass of P. australis (ABP) ranged from 0 g to 1270 g dry weight m-2. ABP was positively correlated to the nitrogen indicator value of the vegetation, but uncorrelated to the soil moisture indicator value. The abundance of 55 of 85 plant species was significantly related to ABP. High ABP was, on an average, associated with low conservation value in terms of species richness, number of rare or endangered species, and proportion of typical mire species. Strong differences were, however, found between plots with tall-herb vegetation (alliance Filipendulion) and plots dominated by heathgrass or small sedges (alliances Molinion and Caricion davallianae). The conservation value of Filipendulion plots was low and decreased significantly with increasing ABP. The conservation value of Molinion and Caricion plots was generally high and not related to ABP. Nevertheless, the current spread of P. australis might reduce the conservation value of Molinion and Caricion meadows in three ways: (1) a direct impact of shading is likely to become apparent only after several years; (2) if P. australis spreads into a site together with tall herbs, the loss of conservation value will be greater than if only tall herbs invade; and (3) if the presence of P. australis increases nutrient availability, it may indirectly cause the spread of tall herbs and the resulting loss of conservation value. Thus, spread of P. australis, spread of tall herbs and increased productivity are strongly related to each other and must be considered together when changes in the vegetation of fen meadows are evaluated. |
| Title: Seasonal variation in methane oxidation by the rhizosphere of Phragmites australis and Scirpus lacustris. |
| Author: van-Der-Nat-Frans-Jaco-W-A; Middelburg-Jack. |
| Source: Aquatic-Botany. June, 1998; 61 (2) 95-110. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Methane oxidation in the rhizosphere of two common wetland plants, reed (Phragmites australis (Cav.) Trin. Ex Steud.) and bulrush (Scirpus lacustris L.), was quantified using the methylfluoride (CH3F) inhibition and anoxic/oxic flux chamber techniques. The similarity of rhizospheric CH4 oxidation rates determined with the two techniques and the absence of an adverse effect of CH3F on plant metabolism indicated that the CH3F inhibition flux chamber technique was a useful tool for measuring rhizospheric CH4 oxidation in freshwater wetlands. A significant seasonal pattern for both plant species as well as a significant difference between the plant species were observed. Light or dark conditions had no significant effect on rhizospheric CH4 oxidation. When averaged over the growing season, CH4 oxidation in the rhizosphere of bulrush and reed reduced the potential CH4 flux by 34.7%+-20.3 and 16.1%+-7.86, respectively. Highest CH4 oxidation rates were noted early in the plant growth cycle with more than 55% of the generated methane being oxidized in the bulrush system. Methane oxidation rates were lowest after plants matured. The difference in rhizospheric CH4 oxidation capacity between reed and bulrush and the seasonal variation for reed were confirmed by a series of slurry incubations. Slurry incubations also showed a significant decrease of potential CH4 oxidation as a function of depth in sediment. |
| Title: Evidence for the vertical distribution of saprophytic fungi on senescent Phragmites australis Culms at Mai Po Marshes, Hong Kong. |
| Author: Poon-M-O-K; Hyde-K-D. |
| Source: Botanica-Marina. May, 1998; 41 (3) 285-292. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: The vertical distribution of fungi on decaying stems and leaf sheaths of Phragmites australis has been investigated in gei wais (tidal shrimp farms) in the intertidal region at Mai Po Marshes, Hong Kong. Fungal communities permanently submerged in the gei wai, are different to those in the intertidal region. Both exhibit a vertical distribution, the latter with a narrower distribution range. The operation of the gei wai has altered the natural vertical distribution of the mycota therein, so that most intertidal fungi occur at the interface between water and air. |
| Title: Above and belowground production of Phragmites australis in the Po Delta, Italy. |
| Author: Scarton-Francesco ; Day-John-W; Rismondo-Andrea. |
| Source: Bollettino-del-Museo-Civico-di-Storia-Naturale-di-Venezia. July 15, 1998 (1999); 49 (0): 213-222. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: From March through October 1995 above- and belowground production for Phragmites australis were studied in a tidally affected reedbed close to the mouth of the Po delle Tolle distributary in the Po Delta. This site is subject to periodic influx of sea water as well as prolonged freshwater conditions during high river flow. Growth took place mostly between May and August. Aboveground production was 876 g d.w./m2, with a peak live biomass of 780 g/m2; belowground production was 2263 g/m2 with a peak live biomass of 4087 g/m2. The net efficiency, with regard to Phragmites australisR, was 1.1%. These production values are comparable with others observed at Mediterranean coastal sites, but regular submersion by salt water probably leads to lower aboveground biomass and higher belowground biomass at the Po Delta site. |
| Title: Effects of salinity and sulfide on the distribution of Phragmites australis and Spartina alterniflora in a tidal saltmarsh. |
| Author: Chambers-Randolph-M ; Mozdzer-Thomas-J; Ambrose-Joelle-C. |
| Source: Aquatic-Botany. Nov., 1998; 62 (3) 161-169. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: In laboratory studies, the short-term response of Phragmites australis and Spartina alterniflora to root immersion in solutions of different salinity and sulfide concentration was measured as the rate of ammonium depletion (a proxy for root uptake) from an initial concentration of 20 muM. From 0 to 20 ppt in the absence of sulfide, ammonium uptake as a function of dry root weight decreased for both Phragmites (from 29.7 +- 3.5 s.e. to 8.2 +- 1.5 mumol N g-1 h-1) and Spartina (from 25.5 +- 3.5 to 9.0 +- 1.5 mumol N g-1 h-1). With an average sulfide concentration of 582 muM at 20 ppt, the rate of ammonium uptake for Spartina (10.9 +- 2.2 mumol N g-1 h-1) was not significantly different from the rate in the absence of sulfide. In contrast, the rate of ammonium uptake was significantly lower for Phragmites when the average sulfide concentration was increased from 0 to 375 muM (1.7 +- 1.6 mumol N g-1 h-1). In a tidal saltmarsh, the average porewater sulfide concentration in Phragmites australis stands (124 +- 206 muM) was almost an order of magnitude lower than that measured in stands of Spartina alterniflora (989 +- 166 muM). These field and laboratory results support the notion that increased sulfide in the rhizosphere reduces the ability of Phragmites to take up nutrients relative to species such as Spartina that are better-adapted to sulfidic soil conditions, thus restricting the distribution of Phragmites in tidal saltmarshes. |
| Title: Effects of litter accumulation and water table on morphology and productivity of Phragmites australis. |
| Author: Clevering,-O.A. |
| Source: Wetlands-Ecology-and-Management [Wetlands-Ecol.-Manage.] 1998 vol. 5, no. 4, pp. 275-287. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Phragmites australis (Common reed) occurs in the interface between water and land. The water depth gradient from deep water to dry land is inversely related to litter accumulation. Eutrophication can result in an excessive production of litter, which may have a large impact on the occurrence of P. australis in this gradient. In an outdoor pot experiment, it was investigated how water tables in combination with substrates containing variable amounts of litter affect morphology and productivity of P. australis. Vegetatively propagated P. australis was grown in pots filled with river sand, litter, and different mixtures of sand and litter (25, 50 and 75% by volume). Four water table treatments were applied; drained (-12 cm), waterlogged (0 cm), flooded (+12 cm), and weekly fluctuating drained and flooded conditions (-12/+12 cm of water relative to substrate level). When drained, no differences between substrate treatments were present. Waterlogging, flooding and fluctuating water table treatments caused growth reduction in substrate containing litter. The plants formed short shoots and thin rhizomes. With increasing water table, allocation of dry matter to stems increased at the expense of leaves and rhizomes. At intermediate levels of litter in the substrate, allocation to leaves was lowest. In both instances a lower leaf weight ratio (LWR) was (partly) compensated for by a higher specific leaf area (SLA), resulting in less pronounced differences in leaf area ratio (LAR). Aquatic roots developed when plants were waterlogged or flooded, and increased when litter was present in the substrate. Aquatic roots were formed in the top soil layer when waterlogged. The percentage of aquatic roots increased with increasing amount of litter in the substrate when plants were flooded. It was concluded that the morphological responses of P. australis to litter strongly constrain its ability to maintain itself in deep water when the substrate contains litter. This might be one of the explanations for the disappearance of P. australis along the waterward side of littoral zones. |
| Title: Rhizome respiration of Phragmites australis: Effect of rhizome age, temperature, and nutrient status of the habitat. |
| Author: Cizkova-Hana ; Bauer-Vaclav. |
| Source: Aquatic-Botany. Aug., 1998; 61 (4) 239-253. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Respiration rates of rhizomes were studied in field populations of Phragmites australis (Cav.) Trin. ex Steud. at three sites of the Trebon Biosphere Reserve (Czech Republic), which were classified (according to plant species composition and phosphorus availability) as oligotrophic, mesotrophic and hypertrophic, respectively. P. australis stands at these sites were expanding, stabilized and retreating respectively. Rhizomes were sampled within the terrestrial parts of the reed stands (at a water depth of about 10 cm). The seasonal course of respiration rate was measured as CO2 release for main age categories of horizontal rhizomes and was supplemented with more detailed studies of age categories of both horizontal and vertical rhizomes. On all sites, the respiration rates remained fairly stable through the year. The mean seasonal respiration rates of 1-year-old horizontal rhizomes were 3.94 +- 0.39, 3.10 +- 0.39 and 2.99 +- 0.39 mumol CO2 g-1 dry wt h-1 (mean +-95% confidence for mean) for Branna, Rozmberk East and Rozmberk West, respectively. The respiration values were inversely related to rhizome age, reaching only 2.66+-0.40, 2.28+-0.40, and 2.72 +- 0.40 in 3-year-old rhizomes at the respective sites. A reverse pattern was found in May when the respiration rates of 3-year-old and 4-year-old rhizomes surpassed those of 1-year-old ones by 0.95, 1.18 and 3.89 mumol CO2 g-1 dry wt h-1 at the three sites, respectively, in 1994, and by 2.08 and 2.51 mumol CO2 g-1 dry wt h-1 at Rozmberk East and Rozmberk West, respectively, in 1997. No substantial differences between sites or age categories were found in the response to temperature at three of four dates investigated; the mean values of the apparent activation energy Ea (including data of all three age categories) were 44.1, 49.0, and 51.2 kJ mol-1 for Branna, Rozmberk East, and Rozmberk West, respectively. The corresponding geometrical means of Q10 values were 1.94, 2.10 and 2.18, respectively. Ea was negatively correlated with age in May yielding an R2 value of 0.55. Branna had the highest respiration rates of all three sites. In 1994 it reached a mean seasonal respiration rate of 3.26 +- 0.23, compared to 2.79 +- 0.23 and 2.74 +- 0.23 mumol CO2 g-1 dry wt h-1 (mean +-95% confidence for mean) for Rozmberk East and Rozmberk West, respectively. Detailed studies performed in 1996 revealed that Rozmberk East had lower respiration rates than Rozmberk West. This difference was largely due to the respiration of the young rhizome parts; thus, subapical segments of newly formed rhizomes reached 13.99 +- 2.16 and 19.28 +- 2.15 mumol CO2 g-1 dry wt h-1, and 1-year-old rhizomes reached 5.25 +- 0.53 and 6.40 +- 0.53 mumol CO2 g-1 dry wt h-1 for Rozmberk East and Rozmberk West, respectively. The differences between sites were relatively small compared to the differences between age categories. |
| Title: Remarkable resistence of Phragmites australis (Cav.) Trin. growing on soils intoxicated by magnesium immissions. |
| Author: Hronec,-O.; Hajduk,-J. |
| Source: Ekologia-Bratisl.-Ecology-Bratisl. 1998 vol. 17, no. 2, pp. 117-124. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Magnesium immissions consist of 65-80 % of MgO. They increase soil alcali reaction up to pH 9.2 and unfavourably turn soil structure from the crumb structure into the prismatic one. On the affected sites, about 10 plant species predominate among which Ph. australis begun to spread, as a new ecotype, during last 20 years. Ph. australis forms mostly elliptic-circular patches of 20-33 m in diameter on the place of former pastures and forests where it did not occur before construction of the magnesium plant. In average, 21 stems (1 fertile) per m super(2) grew up in one year in the close vicinity of the immission source, while 44 (6 fertile) in the distance of 1800 m. Number of internodia did not exceed 22. After Agrostis stolonifera, Phragmites australis shows the highest vitality in such habitats. It grows even on alkaline soils with pH 9.1 and level of Mg and Ca of 13.528 mg.kg super(-1) and 1163 mg.kg super(-1) respectively. Ph. australis is a perspective dominant, resistant and technically usable species exhibiting an antierosive effect and allowing an alternative solution of soil reclamation and vegetation regeneration in surroundings of magnesium plants. |
| Title: Remarkable resistance of Phragmites australis (Cav.) Trin. growing on soils intoxicated by magnesium immissions. |
| Author: Hronec-Ondrej ; Hajduk-Juraj. |
| Source: Ekologia-Bratislava. 1998; 17 (2) 117-124. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Magnesium immissions consist of 65-80% of MgO. They increase soil alcali reaction up to pH 9.2 and unfavourably turn soil structure from the crumb structure into the prismatic one. On the affected sites, about 10 plant species predominate among which Ph. australis begun to spread, as a new ecotype, during last 20 years. Ph. australis forms mostly elliptic-circular patches of 20-33 m in diameter on the place of former pastures and forests where it did not occur before construction of the magnesium plant. In average, 21 stems (1 fertile) per m2 grew up in one year in the close vicinity of the immission source, while 44 (6 fertile) in the distance of 1800 m. Number of internodia did not exceed 22. After Agrostis stolonifera, Phragmites australis shows the highest vitality in such habitats. It grows even on alkaline soils with pH 9.1 and level of Mg and Ca of 13.528 mg.kg-1 and 1163 mg.kg-1 respectively. Ph. australis is a perspective dominant, resistant and technically usable species exhibiting an antierosive effect and allowing an alternative solution of soil reclamation and vegetation regeneration in surroundings of magnesium plants. |
| Title: Cyanidin 3-O-(6"-succinyl-beta-glucopyranoside) and other anthocyanins from Phragmites australis. |
| Author: Fossen-Torgils; Andersen-Oyvind-M. |
| Source: Phytochemistry-Oxford. Oct., 1998; 49 (4) 1065-1068. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Three anthocyanins were isolated from the flowering tops of Phragmites australis. Their structures were elucidated by means of homo- and heteronuclear two-dimensional NMR techniques and mass spectrometry to be cyanidin 3-O-(6"-O-succinyl-beta-glucopyranoside) (2%), cyanidin 3-O-(6"-O-malonyl-beta-glucopyranoside) (64%) and cyanidin 3-O-beta-glucopyranoside (34%). The former pigment, which is a new anthocyanin, represents the first identification of an anthocyanin acylated with succinic acid found outside the dicotyledon genus Centaurea (Compositae). |
| Title: Does mowing in summer reduce the abundance of common reed (Phragmites Australis)? |
| Author: Gusewell-Sabine. |
| Source: Bulletin-of-the-Geobotanical-Institute-ETH. 1998; 64 (0) 23-35. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Common reed (Phragmites australis Trin.) has recently spread in fen meadows of the Swiss Plateau, where it might reduce species richness and displace typical fen species. 2 Mowing experiments were carried out in two fens near Zurich to investigate whether mowing in June (in addition to the usual September cutting) is an effective measure to reduce the abundance of Phragmites. Changes in the number and size of Phragmites shoots were monitored during three years. The aboveground biomass and nutrient concentrations of Phragmites and of all other vascular plant species ("other species") were determined in the third year of the experiment. 3 The additional June cutting had no significant effect on shoot number and size, and, therefore, on the aboveground biomass of Phragmites during this period. The biomass of Phragmites did not differ between treatments, but the biomass of the other species was lower in plots with additional June cutting. Due to this additional cutting, 90% more N and 181% more P were, on an average, removed with Phragmites, but only 30% more N and 64% more P with the other species. Thus, the nutrient economy of Phragmites was stronger affected than the nutrient economy of the rest of the species. 4 The availability of nutrients and interspecific competition are probably decisive for the long-term treatment effects. Further monitoring is needed to evaluate whether mowing in June and September will eventually reduce the abundance of Phragmites by depleting its belowground reserves. However, the results of this study indicate that other means (e.g. grazing) are necessary for a short-term control. |
| Title: Does invasion of oligohaline tidal marshes by reed grass, Phragmites australis (Cav.) Trin. ex Steud., affect the availability of prey resources for the mummichog, Fundulus heteroclitus L.? |
| Author: Fell-Paul-E ; Weissbach-Sonja-P; Jones-Douglas-A; Fallon-Mark-A; Zeppieri-Julie-A; Faison-Edward-K; Lennon-Kristen-A; Newberry-Kate-J; Reddington-Linda-K. |
| Source: Journal-of-Experimental-Marine-Biology-and-Ecology. April 1, 1998; 222 (1-2) 59-77. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Reed grass (Phragmites australis (Cav.) Trin. ex Steud.) has invaded large areas of tidal marsh along the lower Connecticut River and often occurs as a monoculture. Tidal marsh invertebrates (snails, amphipods and isopods) were common to abundant in reed grass-dominated regions, as well as in areas covered by typical tidal marsh vegetation at four sampling stations set up along the salinity gradient. This finding suggests that reed grass marshes provide suitable physical habitat and usable food resources for these semiaquatic detritus/algae feeders. Mummichogs (Fundulus heteroclitus L.) were caught on the high marsh during daylight high tides using Breder traps and an analysis of their gut contents was made. When daylight tides were high enough to cover the marsh surface, mummichogs moved up onto the marsh and fed extensively on marsh invertebrates, both in reed grass marshes and reed grass-free marshes. Such foraging appears to represent a direct trophic link between the marshes and adjacent estuarine waters. Even when tides were not high enough to flood the marsh surface, mummichogs moved into the tidal creeks that course through reed grass marshes and largely reed grass-free marshes and foraged there. With respect to macroinvertebrate populations and mummichog foraging, the reed grass marshes appear to be functioning in essentially the same ways as nearby marshes not invaded by this plant, at least in the short term. |
| Title: Seasonal changes in dissolved amino acids and sugars in basal culm internodes as physiological indicators of the C/N-balance of Phragmites australis at littoral sites of different trophic status. |
| Author: Kohl-Johannes-Guenter ; Woitke-Peter; Kuehl-Harald; Dewender-Marion; Koenig-Gabriele. |
| Source: Aquatic-Botany. March, 1998; 60 (3) 221-240. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: The nitrogen content of different internodes and the dissolved amino acids and sugars of the basal culm internodes of Phragmites australis (Cav.) Trin. ex Steud. were studied monthly in 1994 to estimate the carbon/nitrogen balance at eight sites and lakes. These stands had large differences in standing crop, with less than 400 g shoot dry weight m-2 in a mesotrophic lake and up to 1500 g dry weight m-2 in hypertrophic lakes. No significant differences were found between sites in the nitrate and ammonium concentration of the interstitial water because of very high variability in space and time. The relative nitrogen content (% of dry weight) of different leaves and culm internodes showed significant differences but only between the most different sites. The amount and composition of free amino acids and sugars of the basal culm internodes showed a clear association with the maximum standing crop of the sites. During the later shoot growth phase (July to September), plants of the high productivity sites exhibited a high content of dissolved amino acids in the basal culm internodes with asparagine as the main transport and storage compound, but a very low sugar content with sucrose as the main transport component in summer. At low productivity sites of mesotrophic to moderate eutrophic lakes, this relationship was inverse. The mean of the proportions of total sugars to total amino acids and asparagine to sucrose, respectively, were significantly correlated with the maximum standing crop of the eight sites. Alanine and serine were present in high concentration in early spring before outgrowth of the tiller without pressure induced ventilation of the subtending vertical rhizome parts. The results are discussed with respect to the indicatory value of the amino acid and sugar content of the basal shoot internodes to the productivity of the different stands and their limitation by the nitrogen availability of the plants. |
| Title: Phragmitensis marina gen. et sp. nov., an intertidal saprotroph from Phragmites australis in Hong Kong. |
| Author: Wong-M-K-M; Poon-M-O-K; Hyde-K-D. |
| Source: Botanica-Marina. July, 1998; 41 (4) 379-382. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Phragmitensis marina gen. et sp. nov. is described based on a collection from culms of Phragmites australis made in the intertidal region of Mai Po Marshes and Ting Kok, Hong Kong. The genus is characterized by ascomata form | |
