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排序方式: 共有89条查询结果,搜索用时 46 毫秒
81.
Xiang-Zhong Huang Yue Liu Shi-Shan Yu You-Cai Hu Jing Qu 《植物学报(英文版)》2007,49(11):1615-1618
A new triterpenoid, 11a.O.trans-p-coumaroyltaraxerol (1), along with 11 known triterpenoids, taraxerone (2), taraxerol (3), 2α,3β,23,24-tetrahydroxyolean-12-en-28-oic acid (4), oleanolic acid (5), β-amyrin (6), 3β,23-dihydroxylursan-12-en- 28-oic acid (7), 2α,3β-dihydroxyursan-12-en-28-oic acid (8), 2α,3β,23-trihydroxyursan-12-en-28-oic acid (9), 2α,3β,24- trihydroxyursan-12-en-28-oic acid (10), u rsolic acid (11), and 3-O-acetylursolic acid (12), was isolated from Craibiodendron henryi W. W. Smith (Ericaceae). The structures of these compounds were elucidated on the basis of spectral evidence. Antioxidant activity and vasodilator effect of compound 1 were assessed. 相似文献
82.
以香果树(Emmenopterys henryiOliv.)带芽茎段为外植体,以MS为基本培养基,采用正交实验和单因子实验方法研究了培养温度、无机盐水平、蔗糖、甘露醇和植物生长抑制剂PP333对香果树试管苗离体保存的影响。结果表明,香果树带芽茎段在9℃低温下保存于附加2.0 mg.L-1KT、2.0 mg.L-16-BA、0.1 mg.L-1NAA、50 g.L-1蔗糖和10 g.L-1甘露醇的1/2MS培养基上,180 d后其成活率可达80%。PP333对香果树的离体保存也有显著影响,其中最适合的PP333浓度为6 mg.L-1,180 d后其成活率可达95%以上。离体保存后的试管苗经形态指标和生理生化指标测定以及RAPD分析检测没有发生遗传变异。本实验结果为珍稀濒危植物香果树的种质保存提供了一条简单有效的途径。 相似文献
83.
女贞苦丁茶挥发油成分分析 总被引:13,自引:0,他引:13
苦丁茶是我国南方各民族长期饮用的茶代用品之一,其基原植物种类较多,据调查苦丁茶原植物有9科15种植物,其中木犀科(Oleaceae)女贞属(Ligustrum L.)有粗壮女贞[L. robustum (Roxb.) Bl.]、紫茎女贞(L. purpurascens Y.C.Yang)、序梗女贞(L. pedunculare Rehd)、日本毛女贞(L. japonicum Thunb. var. pubescens Koidz.)等[1~8]. 相似文献
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The distribution of immature Culicoides Latreille (Diptera: Ceratopogonidae) in the intertidal zone was investigated at Redland Bay near Brisbane, southeast Queensland. The aims of this study were to determine the distribution of Culicoides immatures and to identify environmental factors influencing these distributions. Light trapping of adult midges indicated that C.subimmaculatus Lee & Reye, C.marmoratus (Skuse), C.longior Hagan & Reye, C.henryi Lee & Reye, C.cordiger Macfie, may have been breeding in the study site. Soil sampling on six transects traversing mangrove and salt-marsh revealed the breeding habitats from which immature stages of the first four species were obtained. The elevation, vegetation and soils of positive sites were recorded and analysed for each species of Culicoides. The distribution of intertidal vegetation (mangroves and salt-marsh plants) was compared to MacNae's (1966) system of mangrove zonation for eastern Australia. The distribution of immature Culicoides did not correspond with mangrove zones, but was related to the presence or absence of intertidal vegetation. C.subimmaculatus was closely associated with a particular substrate and the presence of burrowing crabs. 相似文献
88.
Rittik Deb Sambita Modak Rohini Balakrishnan 《Proceedings. Biological sciences / The Royal Society》2020,287(1941)
Intense sexual selection in the form of mate choice can facilitate the evolution of different alternative reproductive strategies, which can be condition-dependent. Tree cricket males produce long-distance acoustic signals which are used by conspecific females for mate localization and mate choice. Our study shows that baffling, an acoustic call amplification strategy employed by male tree crickets using self-made tools, is a classic example of a condition-dependent alternative strategy. We show that though most males can baffle, less preferred males, such as smaller and lower-amplitude callers, predominantly use this alternative strategy. Baffling allows these males to increase their call amplitude and advertisement range, which attracts a higher number of females. Baffling also gives these males a mating benefit because females mate for longer durations with them. Our results suggest that the advantage of baffling in terms of gain in the number of sperm cells transferred while mating is primarily limited to less preferred males, thus maintaining the polymorphism of calling strategies in the population. We summarize that baffling is a condition-dependent strategy used by less preferred tree cricket males to obtain mating benefits. 相似文献
89.
Emmenopterys henryi , an endemic species in China , being one of the grade Ⅱ national key conservation rare and endangered plants . Based on the data collected from sample plots, the community structure features in Dapanshan National Natural Reserve of Zhejiang Province were analysed. The results showed that the companion species of E . henryi were evergreen and from Lauraceae and Camelliaceae . The richness index , species diversity index and evenness index in the E. henryi community were low, but ecological dominance index was high . In the community , dominant life form, dominant leaf size , dominant leaf form, dominant leaf texture was phanerophytes, mesophyll , single leaves, herbaceous leaves respectively and whose percentage was 75.9%, 53.97%, 74.70%, 63.86% respectively. The second leaf sizewas microphyll, whose percentage was 36.51%. The spatial patterns of E. henryi population mostly conformed to clump distribution, and the tree layer could be easily divided into 3 sublayers in terms of height. The regeneration of population of E. henryi was poor and the population size was declining. 相似文献