【作者】 刘小林；

【导师】 常朝阳；

【作者基本信息】 西北农林科技大学 ， 植物学， 2008， 硕士

【摘要】 本文在传统形态学分类的基础上,采用常规制片法撕取叶表皮进行光镜观察,结合电镜观察研究了叶表皮的微观形态特征,对秦岭的黄耆属(Astragalus L.)植物进行了分类学研究,得出以下结果:1.经野外调查、标本研究及资料研究,确认秦岭地区共有黄耆属植物32种,其中包括1个亚种和3个变种,其中《秦岭植物志》遗漏种14种。编制了秦岭黄耆属植物的分种检索表,并对每个种的特征和地理分布进行了记述。2.对莲山黄耆(A. leansanicus Ulbr.)和长管萼黄耆(A.limprichtii Ulbr.)的宏观形态及微观形态特征进行对比研究,认为两者的萼筒皆为较明显的管状,荚果皆为线形,支持将二者归为同一组,即将长管萼黄耆从原先的旱生组(Sect.Crasinna(Stev.)Bunge)移至鸟爪组(Sect.Crasinna(Stev.)Bunge)。但是莲山黄耆叶的上表皮无毛,荚果明显较短,两者在丁字毛臂长比和气孔的分布方面也有明显差异,地理分布上各有其独立的分布区,故应为两个独立的物种。3.对秦岭及其周边地区32个种类的解剖学研究表明,这些种类的气孔器均为无规则型,其中簇毛亚属的种类上下表皮都有气孔,黄耆亚属中有些种类上表皮没有气孔,其中尤以膜荚组最为明显,因此可将气孔在上下表皮的分布作为划分组的重要特征。原属于膜荚组的多花黄耆(A. floridus)上下表皮都有气孔,应从本组中分出;而伞序组的文县黄耆(A. wenxianensis)下表皮几乎无气孔,四川黄耆(A. sutchuenensis)明显有相当多的气孔,因此文县黄耆和四川黄耆应恢复为独立的种;紫云英(A. sinicus )上表皮无气孔,这三个种各有特色,是否该划为一组还有待进一步研究。假草木樨组的草珠黄耆(A. capillipes)虽然上表皮叶片上没有气孔,但是叶脉及其附近有相当多的气孔,而且气孔体积较大,呈带状分布,建议将其重新归组。4.扫描电镜观察结果表明,黄耆属植物叶表面多密被表皮毛,角质层厚,其上有蜡质颗粒或片状蜡质层,大多数种类气孔下陷。表皮毛有单毛和丁字毛两种类型,表皮毛表面大多有圆柱状或圆锥状突起,气孔器外拱盖表面光滑或有鳞片状蜡质层。叶表皮形态特征具有一定的稳定性,可以作为分类学的辅助特征。5.根据种的分布区的地理特征将秦岭黄耆属植物划分为6种地理成分,即中国-喜马拉雅成分、古地中海成分、唐古特成分、东北亚至华北成分、欧亚草原至华北成分及秦岭特有成分。秦岭黄耆属植物区系应该是由迁移形成的,因为其特有种比较少,而且特有种的近缘种大都在本区以外。这也充分说明秦岭是我国南北植物区系迁移的通道之一。更多还原

【Abstract】 In this paper we dealt with the taxonomy of the genus Astragalus in Qinling Range, China. The main results are as follows:1. According to filed research and herbarium study, there are 32 species of the genus Astragalus in this area, including one subspecie and three varieties. Of which fourteen were not included in Flora Tsinlingensis. A key to these plants, the description of characteristics and geographical distribution of them were also given.2. The similar morphology of tubular calyx tube and linear pods in A.limprichtii and A. leansanicus indicate the two should be attributed to the same section, supporting a transition of A.limprichtii from Sect.Crasinna(Stev.)Bunge into Sect.Crasinna(Stev.)Bunge. However, the glabrous upper leaf epidermis and obviously shorter pods in A. leansanicus, as well as the differences of hair arm ratio and stomatal distribution pattern between the two species, combined with their adjacent but not overlapped distribution areas, also support that they are independent and good species.3. Micromorphology of 32 species showed that the main stomatal type of Astragalus is anomocytic, and species in Subgen. Pogonophace Bunge are usually amphistomatic, while some species of Subgen. Phaca (Linn.) Bunge are hypostomatic, especially those species in Sect. Canantrum Koch. For this reason, A. floridus should be taken away from this section.The two related species, A. wenxianensis and A. sutchuenensis in Sect. Lotidium Bunge should be treated as independent species because the former has almost no stomata on abaxial surface while the latter has a considerable number of stomata on its abaxial surface. In addition, A. capillipes, a species in Sect. Melilotopsis Gontsch., being of a considerable number of stomata near the midrib of abaxial surface and the stomata being larger in size, should be re-considered of its systematic position.4. The leaf epidermal features under SEM are of some taxonomic significance with its hair morphology, cuticle ornamentation and wax structure. The hairy surface is usually covered with papillae, and sometimes with striation ornamentation. Stomatal rims are often prominent, smooth or sinuous, sometimes with wax granules. These can be used as systematic study of this genus.5. According to the geographical distribution of those species of Astragalus in Qinling Range, six geographical elements can be concluded, namely, the Chinese - Himalayan element, the Palaeo-Mediterranean element, the Tangutica element, the Northeast Asia to North China element, the Eurasian Steppe to North China element and the Qinling Endemic element. The flora of Astragalus in Qinling Range is most likely immigrated from other aeras, for there are few endemic species in this area and the affinities of those endemic species are mainly distributed out of this aera. This also supports the viewpoint that Qinling Range is a transitional area for the flora between Northern and Southern China.更多还原