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肋果沙棘(Hippophae neurocarpa S.W.Liu et T.N.He)自然种群的风媒传粉特征 总被引:1,自引:0,他引:1
野外调查了青藏高原特有植物肋果沙棘的花期物候、开花式样以及风媒传粉特征,对其花粉生活力、柱头可授性及单花花粉量进行了检测.结果表明,肋果沙棘有许多适应风媒传粉的特征:雌雄异株,花小,无花冠,先叶开放,雄花萼片纵裂形成对流的"风洞",花粉近球形,单花花粉量大;雌花柱头细长捻状,伸出萼筒,授粉面大,密布乳突.花粉生活力可以持续16.5 d,柱头可授性为10~20d.肋果沙棘传粉多发生在昼夜温差大的5月中下旬,在多变的气候条件下,种群花期可持续约12~25d,但在晴朗的天气条件下具有爆发性的集中开花机制,是对恶劣条件的适应.重力玻片法检测表明,离花粉源15m左右远的地点花粉密度最大,135m仍能接收到花粉,夜间接收到的花粉数量也很可观,这些研究结果表明,该植物集中在有利的晴朗天气昼夜进行长距离的风媒散粉,能较好地适应青藏高原的复杂环境. 相似文献
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根据对单叶黄荆(Vitex simplicifolia)模式标本的研究,结合在其模式产地的野外调查,发现单叶黄荆与黄荆(V.negundo)并无本质区别,不宜作为独立的种,但其叶片为单叶而且比较稳定,将其降级并组合为黄荆的变种。 相似文献
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四川玉兰属两新种 总被引:1,自引:0,他引:1
描述了中国四川省木兰科玉兰属两新种,北川玉兰(Yulania carnosa D. L. Fu et D. L. Zhang sp. nov.)和时珍玉兰(Y.shizhenii D. L. Fu et F. W. Li sp. nov.)。两新种的独特特征是:北川玉兰每花具佛焰苞状苞片2枚,1枚膜质,着生在花梗中间,另1枚肉质,着生在花梗顶端。时珍玉兰花被片、雄蕊和雌蕊的花柱、柱头均为纯白色;雄蕊约20枚。两新种由傅大立于2001年3月在四川省发现并采集,模式标本存于中国林业科学研究院,模式标本号:北川玉兰No.200103141,时珍玉兰No.200103161。 相似文献
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卵唇山姜 新种 图版ⅠAlpiniaovataZ .L .ZhaoetL .S .Xu ,sp .nov .PlateⅠAbAlpiniastachyoidiHancediffertbracteolisoblongisetlabellisovatis.Herba ,1 .3~ 1 .5malta.Foliaelliptico lanceolata ,31~ 37cmlonga,3.5~ 7.5cmlata ,apiceacuminata,basiangustata ,utrinqueglabra ,marginedensetomentosa,n… 相似文献
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关于顶生金花茶分类地位的探讨 总被引:1,自引:0,他引:1
根据近年来对顶生金花茶和平果金花茶在其原产地的进一步调查和野外观察并参考过去的研究成果,发现:顶生金花茶与平果金花茶在分布、形态特征、物候期、生态习性及细胞学特性,尤其是繁殖器官和生活史等方面都有明显差异。因此,认为将其降为平果金花茶的变种颇为不妥,主张恢复顶生金花茶作为一个独立种的地位,其名称为顶生金花茶。 相似文献
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用气相色谱保留指数定性法、色谱-质谱-计算机联用测定和标准品迭加法分析了木里香橼叶精油的化学成分。从分离出的59个色谱峰中鉴定了31个化合物。其中主要成分是柠檬烯(31.730%)、芳樟醇(1.554%)、香茅醛(23.383%)、香茅醇(1.189%)、橙花醇(11.777%)、香叶醛(16.544%),乙酸香茅酯(1.427%)、乙酸橙花酯(2.258%)、乙酸香叶酯(4.714%)等。把木里香橼叶油与木里香橼果皮油与云南野香橼叶油分别作了比较。结果表明木里香橼叶油中含氧化合物醇、醛、酯的含量相当高,是精油的主要成分,可能作为进口橙叶油的较好的代用品,是一种很有潜力的天然香料资源。 相似文献
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安徽珍稀濒危植物短萼黄连的调查与保护 总被引:2,自引:0,他引:2
2001-2002年对安徽省短萼黄连(Coptis chinensis Franch. Var. Brevisepala W. T. Wang et Hsiao)的分布和群落特征等进行了调查研究.结果显示,短萼黄连在安徽省境内仅分布于皖南山区,海拔600~1 600 m;其群落组成成分共计39种,隶属于31科37属,群落物种多样性较丰富.开垦、修路等人类活动,特别是过度采挖已造成短萼黄连资源的严重破坏,致使现有短萼黄连种群数量少,规模小,至今未得到有效保护,为此,提出了相关保护对策. 相似文献
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Somatostatin lowers the cytosolic free Ca2+ concentration in clonal rat pituitary cells (GH3 cells) 总被引:4,自引:0,他引:4
Changes in the cytosolic free Ca2+ concentration, [Ca2+]i, have been proposed to mediate the regulation of the secretion of pituitary hormones by hypothalamic peptides. Using an intracellularly trapped fluorescent Ca2+ probe, quin2, [Ca2+]i was monitored in GH3 cells. Somatostatin lowers [Ca2+]i in a dose dependent manner from a prestimulatory level of 120 +/- 4 nM (SEM, n = 13) to 78 +/- 9 nM (n = 5) at 10(-7)M; the effect is half maximal at 2 X 10(-9) M somatostatin. The decrease in [Ca2+]i occurs rapidly after somatostatin addition and a lowered steady state [Ca2+]i is maintained for several minutes. Somatostatin does not inhibit the rapid rise in [Ca2+]i elicited by thyrotropin releasing hormone (TRH) and can still cause a decrease in [Ca2+]i in the presence of TRH (10(-7)M). Concomitantly with its action on [Ca2+]i somatostatin causes hyperpolarization of GH3 cells assessed with the fluorescent probe bis-oxonol. The lowering of [Ca2+]i by somatostatin is however not only due to reduced Ca2+ influx through voltage dependent Ca2+ channels, since it persists in the presence of the channel blocker verapamil. These results suggest that somatostatin may exert its inhibitory action on pituitary hormone secretion by decreasing [Ca2+]i. 相似文献
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A new orchid genus, Ypsilorchis Z. J. Liu, S. C. Chen & L. J. Chen, is established based on Ypsilor-chis fissipetala (Finet) Z. J. Liu, S. C. Chen & L. J. Chen (basionym: Liparis fissipetala Finet). The new genus differs from Liparis and its allies by having two granular-waxy pollinia each with a somewhat elastic caudicle, deeply bilobed petals and strongly crisped-margined leaves with an apical awn to 1 mm long. These features are an indication of its distant relation to the members of the subtribe Liparidinae, and thus a new subtribe, Ypsilor-chidinae Z. J. Liu, S. C. Chen & L. J. Chen, is proposed. 相似文献