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作 者 ：张志勇 李德铢

期 刊 ：云南植物研究 2003年 25卷 05期 页码：1-3

关键词：五针白皮松；遗传多样性；RAPD；保护；

Keywords:Magnolia,

摘 要 ：用随机扩增多态(RAPD)方法对极度濒危植物五针白皮松(Pinus squamata X.W.Li)的遗传多样性和居群遗传结构进行了研究。14个随机引物共获得93条RAPD谱带，其中6条为多态带，多态位点百分率仅为645%，遗传多样性极低。Shannon指数I和Nei指数h在种内也只有0020和0030，两个亚居群间(半阴坡亚居群与半阳坡亚居群)遗传分化程度不高，遗传分化系数Gst只有0110，与大多数松科植物近似，居群每代迁移数为4032。五针白皮松极低的遗传多样性可能是由于它在演化过程中遭受过严重的灾害，造成严重的瓶颈效应，丧失其大部分遗传变异。在随后的演化过程中由于遗传漂变、自交衰退等小种群现象，导致遗传多样性的进一步丧失。另外，阔叶树种对其生存的挤压和人类的干扰也是导致五针白皮松遗传多样性降低的因素之一。本文最后对该结果的保护生物学意义进行了评价。

Abstract:Pollen morphology of five species from Magnolia is similar under LM.The sculptures are all foveolate except Magnolia grandiflora slightly coarse.The exine of the five species can be distinguished into tectum,columella and footlayer.The puncta in the tectum are clearly seen.The colpus memberane consists of a thin footlayer and intine while the sexine elements (tectum and columella) are reduced gradually.Spherical granules are frequently observed and mixed up with the small intraexinous spaces of several incipient columellae sometime in columella.Endexine very thin,distinct and continuous in Mgrandiflora and beneath the apertural area in Mdenudata.The development of columella speaks in favour of regarding the pollen of Magnolia as primitive.

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