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排序方式: 共有287条查询结果,搜索用时 15 毫秒
1.
研究了桑属植物5个种32个品种的染色体倍数性,发现宽城10号等9个品种为三倍体(2n=3x=42),其余为二倍体(2n=2x=28)。 相似文献
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本文运用酶解去壁低渗法,对贵州省桑属植物种质资源材料27份进行了染色体倍数性研究。结果如下:1.二倍体(2n=2x=28)5个。2.三倍体(2n=3x=42)1个。3.六倍体(2n=6x=84)21个。丰富了桑属植物染色体研究内容,为桑树遗传育种提供了理论和实践依据。 相似文献
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Rosellinia (Xylariaceae) is a large, cosmopolitan genus comprising over 130 species that have been defined based mainly on the morphology of their sexual morphs. The genus comprises both lignicolous and saprotrophic species that are frequently isolated as endophytes from healthy host plants, and important plant pathogens. In order to evaluate the utility of molecular phylogeny and secondary metabolite profiling to achieve a better basis for their classification, a set of strains was selected for a multi-locus phylogeny inferred from a combination of the sequences of the internal transcribed spacer region (ITS), the large subunit (LSU) of the nuclear rDNA, beta-tubulin (TUB2) and the second largest subunit of the RNA polymerase II (RPB2). Concurrently, various strains were surveyed for production of secondary metabolites. Metabolite profiling relied on methods with high performance liquid chromatography with diode array and mass spectrometric detection (HPLC-DAD/MS) as well as preparative isolation of the major components after re-fermentation followed by structure elucidation using nuclear magnetic resonance (NMR) spectroscopy and high resolution mass spectrometry (HR-MS). Two new and nine known isopimarane diterpenoids were identified during our mycochemical studies of two selected Dematophora strains and the metabolites were tested for biological activity. In addition, the nematicidal cyclodepsipeptide PF1022 A was purified and identified from a culture of Rosellinia corticium, which is the first time that this endophyte-derived drug precursor has been identified unambiguously from an ascospore-derived isolate of a Rosellinia species. While the results of this first HPLC profiling were largely inconclusive regarding the utility of secondary metabolites as genus-specific chemotaxonomic markers, the phylogeny clearly showed that species featuring a dematophora-like asexual morph were included in a well-defined clade, for which the genus Dematophora is resurrected. Dematophora now comprises all previously known important plant pathogens in the genus such as D. arcuata, D. bunodes, D. necatrix and D. pepo, while Rosellinia s. str. comprises those species that are known to have a geniculosporium-like or nodulisporium-like asexual morph, or where the asexual morph remains unknown. The extensive morphological studies of L.E. Petrini served as a basis to transfer several further species from Rosellinia to Dematophora, based on the morphology of their asexual morphs. However, most species of Rosellinia and allies still need to be recollected in fresh state, cultured, and studied for their morphology and their phylogenetic affinities before the infrageneric relationships can be clarified. 相似文献
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Nicola C. Okes Philip A.R. Hockey Lorien Pichegru Carl D. van der Lingen Robert J.M. Crawford David Grmillet 《Biological conservation》2009,142(10):2361-2368
In the southern Benguela upwelling ecosystem off the west coast of South Africa, seabird populations are decreasing dramatically because of reduced availability of pelagic fish. We tested the hypothesis that the west coast fishing industry is competing for the remaining stocks of anchovy and sardine with the largest colony of Vulnerable Cape Gannets (Morus capensis) along the Atlantic coast. Using GPS-tracking of the birds, echo-sounding of pelagic fish, and vessel log books, we located overlap areas between bird foraging ranges, pelagic fish distribution, and fishing activities. We then compared fish catches by gannets and vessels within their joint foraging zones. In October 2007, purse-seine fishing grounds and gannet foraging areas overlapped by only 13%. However, for a 1-month period, the amount of fish removed from this area by purse-seine boats amounted to 41% of the food requirements of the 72,000 gannets breeding on Malgas Island (25% of the world population). The fishery’s catch in this area is significant in terms of its potential impact on gannets, but comprises only 3.6% of total fishery catch. Based on this finding, the rapidly decreasing size of the gannet colony and the stated objectives of South Africa’s Marine Living Resources Act of 1998, the case for considering and experimenting with at-sea ‘no-take’ areas for the purse-seine fishery is strong. Efforts to establish whether ‘no-take’ fishing zones increase food availability for top predators is an important next step in conservation of the southern Benguela Ecosystem. 相似文献
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鉴定了烟属植物野生种生育期等植物学性状特性,评价了供试材料对黑胫病(0号及1号生理小种)的抗性,为开展远缘杂交花期相遇及亲本选配提供了基础数据。在玻璃温室内,本研究针对66份烟属植物野生种的生育期等7个植物学性状的调查,检测了烟碱及钾含量,并对黑胫病(0号及1号生理小种)抗性进行了评价。结果表明:供试材料播种到开花时间(DF)为35.00~357.00 d,平均121.67 d;种子千粒重(TSW)为0.02~0.20 g,平均0.09 g;株高(PH)为11.20~292.75 cm,平均119.19 cm;花冠长度(CL)为1.22~11.50 cm,平均3.98 cm;花冠直径(CD)0.67~7.80 cm,平均2.37 cm;最大叶长(MLL)为6.79~61.15 cm,平均25.17 cm;最大叶宽(MLW)为0.65~35.51 cm,平均11.84 cm。烟碱含量为0.03%~1.81%,平均0.34%;钾含量为0.32%~7.11%,平均3.56%。筛选到N.alata PI42334等11份资源同时抗黑胫病0及1号生理小种。 相似文献
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落羽杉中山杉系列新品种选育初报 总被引:4,自引:1,他引:3
报道了落羽杉属(Taxodium)中山杉系列‘Zhongshansha’杂交新品种选育结果。以经国家林木良种审定委员会审定推广的优良品种中山杉302‘Zhongshansha302’为母本,与父本墨西哥落羽杉(T.mucronatum)回交,获得回交代杂种200个以上。通过苗期实生初选和无性系复选以及不同立地的栽植试验,初选出优于或相似于亲本中山杉302的系列新品种中山杉1号、9号、24号、27号、46号、86号、91号、102号、118号、136号、146号、149号等12个。其中中山杉1号、24号、27号、86号、102号、118号、136号、146号具有一定的耐盐碱能力,可在池杉(T.ascen-dens)、落羽杉(T.distichum)不宜栽植的盐碱地上绿化造林。 相似文献
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