SAIN Invasive Plant Pests Resource Collection for Hieracium aurantiacum
Common name: Orange hawkweed
| Title: Four introduced species new to Saskatchewan from the 1990s. |
| Author: Hudson-John-H . |
| Source: Blue-Jay. 58 (2): 91-94. |
| Source Type: Journal |
| Publication Date: 2000 |
| Abstract: NA |
| Title: Monogenic inheritance of apomixis in two Hieracium species with distinct developmental mechanisms. |
| Author: Bicknell-R-A ; Borst-N-K; Koltunow-A-M. |
| Source: Heredity-. 84 (2): 228-237. |
| Source Type: Journal |
| Publication Date: 2000 |
| Abstract: Apomixis, the asexual formation of seed, has been known in angiosperms for more than a century yet the genetic mechanisms that control this trait remain poorly understood. Most members of the genus Hieracium are apomicts, forming predominantly asexual seed. Some purely sexual forms, however, also exist. In this paper we present a study of the inheritance of apomixis using two apomictic species of Hieracium which utilize very different forms of megagametogenesis. In both cases the progeny inherited apomixis as a monogenic, dominant trait that could be transferred by both haploid and diploid male gametes. In common with observations from other systems, no diploid apomictic progeny were recovered from these crosses. This appears to have been caused by selection against the survival of diploid zygotes, rather than against the mediation of haploid gametes as has been noted in other systems. Crosses between the two apomicts showed that the dominant determinants in the two forms examined were closely linked, possibly allelic. The significance of these data is discussed with respect to current theories on the associative link between gametophytic apomixis and polyploidy. |
| Title: Population dynamics of endangered species in a transplanted montane meadow. |
| Author: Bruelheide-Helge . |
| Source: Folia-Geobotanica. [print] 2000; 35 (2): 179-189. |
| Source Type: Journal |
| Publication Date: 2000 |
| Abstract: Species turnover and mobility on a scale of 25 m2 was studied in a montane meadow, which had been transplanted to a location 200 m away from the initial site in the Harz Mountains. The transplantation was performed to preserve this grassland area, which otherwise would have been destroyed by a road construction project. The frequency of 18 endangered species was recorded annually from 1992 to 1996 in 122 quadrats, having a size of 5 X 5 m and being arranged in a coherent block with a total area of 3,000 m2. Many species showed considerable dynamics in settling in the quadrats. The species mobility was expressed as turnover rate, as persistence and as increase in cumulative species frequency. Mean turnover rates in quadrats over the study period ranged from 0.0% to 20.9% for Ranunculus platanifolius and Viola tricolor, respectively. The lowest annual persistence was found for Lilium martagon with 0.582, followed by Viola tricolor with 0.625. For the majority of species, persistence with regard to the first year did not decrease during the investigational period; exceptions were the decreasing persistence of Polygala vulgaris, Thesium pyrenaicum and Viola tricolor. In all cases, the cumulative frequencies were significantly lower than would had been expected on a random basis. Even the most mobile species showed cumulative frequencies which closely approximated the lowest possible values, thus supporting the minimum mobility model which proceeds from allocating occurrences to the cells in which the species previously occurred. In general, mobility on a scale of 25 m2 was much lower than had been demonstrated by various authors on smaller scales. However, mobility studies on a large scale are useful because they focus on certain aspects of mobility such as life span of individuals and seed dispersal. For the investigated species can be concluded that the low mobility rate was not sufficient for their establishment in new grid cells to a considerable extent. |
| Title: Hieracium derubellum, a necessary taxonomic repositioning. |
| Author: Gottschlich-G ; Schuhwerk-F. |
| Source: Berichte-der-Bayerischen-Botanischen-Gesellschaft-zur-Erforschung-der-Heimischen-Flora. [print] 2000; 69-70: 147-150. |
| Source Type: Book |
| Publication Date: 2000 |
| Abstract: NA. |
| Title: Apomixis is not developmentally conserved in related, genetically characterized Hieracium plants of varying ploidy. |
| Author: Koltunow-Anna-M ; Johnson-Susan-D; Bicknell-Ross-A. |
| Source: Sexual-Plant-Reproduction. April, 2000; 12 (5): 253-266. |
| Source Type: Journal |
| Publication Date: 2000 |
| Abstract: Apomixis is facultative in characterized members of the genus Hieracium. The three components that comprise the apomictic mechanism include apospory followed by autonomous embryo and endosperm formation. The time of aposporous embryo sac initiation and mode of embryo sac formation are different in Hieracium piloselloides (D3) and Hieracium aurantiacum (A3.4). Genetic studies have shown that a single dominant locus encodes all three components of apomixis in both species (Bicknell et al. 2000). We histologically examined a range of related, genetically characterized apomictic Hieracium plants derived from D3 and A3.4 to assess conservation of the apomictic mechanism in different genetic backgrounds. The plants varied in ploidy, and also in the amount of DNA introduced from sexual Hieracium pilosella (P4). An apomictic hybrid from a cross between the two apomicts was also examined. The developmental processes observed in the parental apomicts were not conserved in the examined plants and alterations occurred in the components of apomixis. One plant also exhibited adventitious embryony. The results show that other genetic factors can modify apomixis with respect to time of initiation, spatial location, and mode of developmental progression. Both the apomictic locus and the modifiers are essential for efficient penetrance of the trait in Hieracium. Some of the findings in Hieracium correspond with observations in Ranunculus and this is discussed in terms of models for apomictic development and the control of apomixis in crops. |
| Title: Orange Hawkweed Hieracium aurantiacum L.: A new naturalised species in alpine Australia. |
| Author: Morgan-John-W. |
| Source: Victorian-Naturalist-Blackburn. 117 (2): 50-51. |
| Source Type: Journal |
| Publication Date: 2000 |
| Abstract: Orange Hawkweed Hieracium aurantiacum L. is a new species for mainland Australia. It has been planted at Falls Creek and potentially threatens subalpine communitites. Efforts are underway to control the species. |
| Title: Chromosome numbers and reproductive systems in selected representatives of Hieracium subgen. Pilosella in the Krkonose Mts (the Sudeten Mts). |
| Author: Krahulcova-Anna ; Krahulec-Frantisek. |
| Source: Preslia-Prague. 71 (3): 217-234. |
| Source Type: Journal |
| Publication Date: 1999 |
| Abstract: Chromosome numbers and reproductive systems are given for the following taxa of Hieracium subgen. Pilosella occurring in the Krkonose Mts: H. pilosella L. (2n = 36, sexual), H. lactucella Wallr. (2n = 18, sexual), H. caespitosum Dumort. (2n = 36, the mode of reproduction unknown), H. aurantiacum L. (2n = 36, apomictic), H. schultesii F.W. Schultz (2n = 36, sexual; 2n = 45, apomictic), H. macrostolonum G. Schneider (2n = 54, the mode of reproduction unknown), H. glomeratum Froel. (2n = 36, 45, both apomictic), H. floribundum Wimm. et Grab. (2n = 36, apomictic), H. iseranum Uechtr. (2n = 36, apomictic), H. apatelium Nageli et Peter (2n = 36, both sexual and apomictic; 2n = 54, apomictic), H. piloselliflorum Nageli et Peter (2n = 36, the mode of reproduction unknown; 2n = 45, 44, apomictic; 2n = 54, apomictic), H. stoloniflorum Waldst. et Kit. (2n = 54, apomictic), H. rubrum Peter (2n = 54, apomictic). Chromosome numbers are reported for the first time for H. apatelium, H. iseranum, and H. piloselliflorum, a new chromosome number was determined for H. macrostolonum and H. schultesii. The group of species (H. caespitosum, H. glomeratum, H. floribundum, H. iseranum) has been found to have a single long marker chromosome in the karyotype; this fact supports the view of their relationship. The mode of reproduction is here examined for the first time in polyploid hybridogenous species H. iseranum, H. apatelium, H. piloselliflorum, H. stoloniflorum, H. rubrum and H. schultesii from nature; the apomictic reproduction of tetraploid H. floribundum and of pentaploid H. glomeratum is also a new information. The variation of Hieracium subgen. Pilosella in the Krkonose Mts is discussed in connection with the presence of at least four sexual types and diversity of reproductive systems. The occurrence of H. stoloniflorum in the Krkonose Mts is dealt with. |
| Title: Floristic survey of Rabun County, Georgia: Part II. |
| Author: Stiles-Billy-J; Howel-Carol-L. |
| Source: Castanea-. 63 (2) 154-160. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: This paper represents the continuation of an investigation into the Flora of Rabun County, Georgia, begun by the staff of the Louise Gallant Herbarium in 1989, and presents the results of approximately 70 field trips made during the 1995 and 1996 collecting seasons. A brief site description is followed by the presentation of a catalogue of vascular plants. The survey records 273 species, 158 county records, 6 species new to Georgia, and 5 species listed as Special Concern by the Georgia Department of Natural Resources. 972 vascular plant species are now recorded for Rabun County. |
| Title: Sexual and apomictic development in Hieracium. |
| Author: Koltunow-Anna-M ; Johnson-Susan-D; Bicknell-Ross-A. |
| Source: Sexual-Plant-Reproduction. Sept., 1998; 11 (4) 213-230. |
| Source Type: Journal |
| Publication Date: 1998 |
| Abstract: Most members of the genus Hieracium are apomictic and set seed without fertilization, but sexual forms also exist. A cytological study was conducted on an apomictic accession of H. aurantiacum (A3.4) and also H. piloselloides (D3) to precisely define the cellular basis for apomixis. The apomictic events were compared with the sexual events in a self-incompatible isolate of H. pilosella (P4). All plants were maintained as vegetatively propagated lines each derived from a single plant. Sexual P4 exhibited characteristic events of polygonum-type embryo sac formation, showed no latent apomictic tendencies, and depended upon fertilization to set seed. In contrast, D3 and A3.4 were autonomous aposporous apomicts, forming both embryo and endosperm spontaneously inside an unreduced embryo sac. The two apomicts exhibited distinct mechanisms, but variation was also observed within each apomictic line. Seeds from apomicts often contained more than one embryo. A degree of developmental instability was also observed amongst germinated seedlings and included variation in meristem and cotyledon number, altered phyllotaxis, callus formation, and seedling fusion. In most cases abnormal seedlings developed into normal plants. Such phenomena were not observed following germination of hybrid seeds derived from crosses between sexual P4 and the apomictic plants. The three plants can now be used in inheritance studies and also to investigate the molecular mechanisms controlling apomixis. |
| Title: Isolation of a diploid, apomictic plant of Hieracium aurantiacum. |
| Author: Bicknell-R-A. |
| Source: Sexual-Plant-Reproduction. 1997; 10 (3) 168-172. |
| Source Type: Journal |
| Publication Date: 1997 |
| Abstract: As in most taxa that contain gametophytic apomicts, all of the apomictic biotypes studied so far in the genus Hieracium subgenus Pilosella have been recorded as polyploids. As part of a study of variation in apomictically derived populations of H. aurantiacum, a diploid plant was identified. Apospory, the mechanism of apomixis typically observed in this taxon, was observed in this plant. Unreduced megagametophytes at various developmental stages were commonly observed in the developing ovules, and endosperm formation was autonomous. The eventual seed set, however, was low. This appears to have been due to the proliferation of competing megagametophytes and embryos within each ovule. Pollen sterility was also observed, primarily resulting from the dysfunction of microgametogenesis at the uninucleate stage. |
| Title: Isolation of a diploid, apomictic plant of Hieracium aurantiacum. |
| Author: Bicknell, R. A. |
| Source: Sexual plant reproduction. v 10 n 3 168. |
| Source Type: Journal |
| Publication Date: 1997 |
| Abstract: NA. |
| Title: Use of endomycorrhizal fungi for plant cultivation on buildings. |
| Author: Busch-E; Lelley-J-I. |
| Source: Journal-of-Applied-Botany. 1997; 71 (1-2) 50-53. |
| Source Type: Journal |
| Publication Date: 1997 |
| Abstract: Species of Sedum, Festuca, Anthemis, Hieracium, Potentiella, Allium, and Dianthus were cultivated in a myc-s substrate enriched with a spore mixture of defined strains of arbuscular mycorrhizal fungi (AMF) and a substrate containing the natural AMF population (controls). After three months the mycorrhizal infections and biomass production of myc-s plants and controls were measured. The need of selecting specialized strains of arbuscular mycorrhizal fungi for commercial inoculum production providing optimal growth of certain cultivated plants is discussed. |
| Title: Flower delight in Torphagen. |
| Author: Lindberg-Per-Sigurd. |
| Source: Fauna-och-Flora-Stockholm. 1996; 91 (2-3) 40-43. |
| Source Type: Journal |
| Publication Date: 1996 |
| Abstract: NA |
| Title: Determination of the ploidy level in the genus Hieracium subgenus Pilosella (Hill) S.F. Gray by flow cytometric DNA analysis. |
| Author: Braeutigam-Siegfried ; Braeutigam-Edeltraut. |
| Source: Folia-Geobotanica-et-Phytotaxonomica. 31 (3) 315-321. |
| Source Type: Journal |
| Publication Date: 1996 |
| Abstract: Ploidy levels of 8 taxa of the genus Hieracium subgenus Pilosella collected from the same locality were determined by means of flow cytometric estimation of relative nuclear DNA content. The DNA analysis of isolated nuclei stained with propidium iodide was performed with a flow cytometer equipped with an argon-ion laser. The diploid species H. lactucella (2n=18) was used as internal standard. As a rule 20 individuals per taxon were analysed. The flow cytometric analysis proved to be a rapid, accurate and sensitive method for screening of ploidy levels. Considering the known cytological data; the following ploidy levels were determined: H. aurantiacum 4x, H. pilosella 4x, H. piloselloides 4x, H. bauhini 5x, H. caespitosum 5x, H. stoloniflorum 4x, H. brachiatum 4x and 6x, H. leptophyton 7x. H. piloselloides, H. bauhini and H. caespitosum yield relative DNA contents which are the exact multiples of the haploid DNA content of H. lactucella. In the case of H. pilosella the haploid DNA content is lower than that predicted from the diploid, namely 0.43 instead of the expected 0.5. The haploid 1x DNA contents of both H. brachiatum and H. leptophyton range between the value found for H. pilosella and those for the other investigated species, confirming their hybrid origin. |
| Title: New vascular plant records for the Black Hill of South Dakota and Wyoming. |
| Author: Larson-Gary-E; Johnson-James-R. |
| Source: Prairie-Naturalist. 1995; 27 (2) 115-121. |
| Source Type: Journal |
| Publication Date: 1995 |
| Abstract: Fifteen taxa are added to the vascular flora of the Black Hills as a result of recent field investigations. Twelve of the taxa are new records for South Dakota and one species is a new record for Wyoming. Seven of the new records are introduced species that only recently have been found growing wild in the Black Hills; four of these are newly recorded for the Great Plains region. The remaining eight taxa are native to the northern Great Plains region, but their documentation in South Dakota represents an extension of natural range. Of the fifteen added taxa, Torreyochloa pallida var. pauciflora has actually been attributed to the Black Hills by some authors but is overlooked by the most recent floristic treatments covering the area. One of the new records for South Dakota is the hybrid, Salix times clarkei, a naturally occurring cross between S. candida and S. petiolaris. |
| Title: In vitro allelopathic effects of pollen from three Hieracium species (Asteraceae) and pollen transfer to sympatric Fabaceae. |
| Author: Murphy-Stephen-D; Aarssen-Lonnie-W . |
| Source: American-Journal-of-Botany. 1995; 82 (1) 37-45. |
| Source Type: Journal |
| Publication Date: 1995 |
| Abstract: Pollen allelopathy occurs when pollen toxins inhibit sexual reproduction in heterospecifics. To quantify pollen allelopathic effects in vitro, pollen of Hieracium aurantiacum, H. floribundum, and H. pratense was extracted with double distilled water into concentrations of 0 (control), 0.1, 1, 3, 5, 10, and 25 pollen grains/mu-l. A subset of these extracts was partitioned by ion-exchange chromatography into acidic, basic, and neutral fractions. Pollen from six sympatric species of Fabaceae (Lotus corniculalus, Medicago sativa, Trifolium hybridum, T. pratense, T. repens, Vicia cracca) and the species of Hieracium was germinated on agar media containing different extract concentrations. As extract concentrations from intact pollen or from acidic fractions increased, mean percent germination of pollen of all Fabaceae decreased nonlinearly. Extract concentrations of 0.1 grains/mu-l and above inhibited pollen germination in the Fabaceae. In no case was any Hieracium species affected, i.e., there was no autotoxicity. Similar results were obtained using plants from nine populations of H. floribundum and H. pratense across eastern Canada. Observation of floral visitors indicated that there were relatively few movements between Hieracium and the Fabaceae (about 15% of total visits). Hence there is limited opportunity for heterospecific pollen transfer. This was consistent with censuses of stigma, i.e., few pollen grains of Hieracium were found on stigma of the Fabaceae. Thus, pollen allelopathy in Hieracium is unlikely to affect reproductive success in these six species of Fabaceae. |
| Title: Micropropagation of Hieracium aurantiacum. |
| Author: Bicknell-R-A. |
| Source: Plant-Cell-Tissue-and-Organ-Culture. 1994; 37 (2) 197-199. |
| Source Type: Journal |
| Publication Date: 1994 |
| Abstract: Hieracium aurantiacum L. is being investigated as a model system for studying the genetic basis of gametophytic apomixis. Micropropagation methods were developed for the multiplication and maintenance of unique genotypes, and to facilitate the development of an Agrobacterium-mediated transformation procedure. A basal medium containing Murashige & Skoog macro- and micro-salts, B5 vitamins and 3% sucrose was used throughout. Shoot regeneration from leaf disks was optimized on a medium supplemented with 2.5 mu-M indole-3-butyric acid (IBA) and 2.2 mu-M 6-benzyladenine (BA). Shoot proliferation was optimized using 2.2 mu-M BA, without additional IBA, giving 5-fold shoot-tip multiplication rates every 4 weeks. Shoots readily formed roots on the basal medium and could be transplanted to potting medium 3 weeks later. Micropropagation was found to have no effect on the expression of apomixis in this species. |
| Title: Agrobacterium-mediated transformation of Hieracium aurantiacum. |
| Author: Bicknell-R-A ; Borst-N-K. |
| Source: International-Journal-of-Plant-Sciences. 1994; 155 (4) 467-470. |
| Source Type: Journal |
| Publication Date: 1994 |
| Abstract: An Agrobacterium-mediated transformation system, based on the neomycin phosphotransferase II (NPTII) gene, is described for the apomictic plant Hieracium aurantiacum. Integration of foreign DNA was confirmed by Southern analysis and its "pression demonstrated by assaying for NPTII enzymatic activity. NPTII activity, which confers kanamycin resistance, was inherited by clonal seedlings of transformed plants. Growth of untransformed seedlings was inhibited by 20 mg/L kanamycin, while transformants continued to grow at 300 mg/L. The clarity of the response, together with the convenience of screening at the seedling stage, makes kanamycin resistance a valuable tool for quantifying reproductive mechanisms in facultatively apomictic plants of this species. |
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