中国蓝果树属分类学与极度濒危植物云南蓝果树保护生物学
其他题名Taxtonomy of Nyssa L.(Nyssaceae) and Conservation Biology of Nyssa yunnanensis, a Critically Endangered Species
孙宝玲
学位类型博士
导师张长芹
2008-06-06
学位授予单位中国科学院昆明植物研究所
学位授予地点昆明植物研究所
学位专业植物学
关键词蓝果树属 形态学 分子系统学 分类学 分类修订 细胞学 种子生物学 传粉生态学 保护遗传学 保护生物学
摘要蓝果树属(Nyssa L.)是东亚-北美间断分布的孑遗植物属。中国植物志记载我国分布7种,其中5种为中国特有。本文通过对蓝果树属植物的形态学和分子系统学的比较分析,结合野外观察和标本查证对中国蓝果树属植物进行了分类学修订,确定了极度濒危植物云南蓝果树(Nyssa yunnanensis W. C. Yin ex H. N. Qin & Phengklai)的分类地位,并对云南蓝果树进行了资源调查、细胞学、传粉生物学和保护遗传学研究,探讨了其濒危原因及相应的解危措施。主要研究结论如下: 1.形态学研究 通过对中国分布的6种蓝果树属植物的33个质量性状和19个数量性状进行统计分析及主成分分析,结果显示云南蓝果树与华南蓝果树(N. javanica (Bl.) Wanger.)能明显区分,是个好种;中国蓝果树(N. sinensis Oliv.)、瑞丽蓝果树(N. shweliensis (W. W. Smith) Airy-Shaw)、上思蓝果树(N. shangszeensis Fang et Soong)和文山蓝果树(N. wenshanensis Fang et Soong)不能明显区分。薄叶蓝果树(N. leptophylla Fang et Chen)由于模式标本无采集人及采集地点,无法采集数据,未进行统计分析。 2.分子系统学研究 以喜树(Camptotheca acuminate Decne.)、珙桐(Davidia involucrata Baill.)为外类群,除了选取中国分布的蓝果树植物外,还选取了北美的多花蓝果树(N. sylvatica Marsh)、水蓝果树(N. aquatica L.)作为研究对象,通过核基因ITS片段和5个叶绿体基因片段的最大简约性分析及联合分析,支持形态学研究的结论。云南蓝果树与华南蓝果树是蓝果树属植物的基部类群,二者亲缘关系较近。中国蓝果树、瑞丽蓝果树、上思蓝果树和文山蓝果树应予以归并,他们与多花蓝果树的亲缘关系更近。 3.中国蓝果树属植物的分类学修订 结合上述对中国蓝果树属植物形态学和分子系统学的研究结果,对中国蓝果树属植物进行了分类修订,认为中国目前分布3个种,即云南蓝果树、华南蓝果树和中国蓝果树,薄叶蓝果树(N. leptophylla Fang et Chen)做存疑种处理。 4.极度濒危植物云南蓝果树的生物学特性 该植物分布范围狭窄,仅分布在云南省西双版纳的普文,现仅有两个居群,野外个体数量仅37株,常绿大乔木,形态上的雄性两性异株植物,是热带北缘针阔叶混交林的上层树种,生长在溪边沟谷,林下无幼苗,自然更新差。 5.云南蓝果树的种子萌发特性研究 观察了云南蓝果树种子萌发形态,初步研究了萌发基质、光照、人工破坏内果皮和pH梯度碱液处理对云南蓝果树种子萌发的影响。结果表明:云南蓝果树种子(带内果皮)平均大小为0.94 cm×0.52 cm×0.17 cm(长×宽×厚),千粒重约234.3 g,有萌发瓣;红土/腐殖土/泥炭土(v/v/v,1:1:1) 为云南蓝果树种子萌发的适宜基质;种子在光、暗条件下都能萌发;人工破坏内果皮能提高种子的萌发率;碱液处理对云南蓝果树种子的萌发有抑制作用。 6.云南蓝果树的细胞学研究 云南蓝果树的染色体数目为2n=44,与前人研究该属其他植物的染色体数目相同,不同在于该种存在B-染色体,可能与该种濒危有一定的关系。 7.云南蓝果树的传粉生态学研究 通过研究云南蓝果树的开花物候、花粉的萌发率和形态特征、性别比例、传粉媒介及交配系统,结果表明云南蓝果树雄花的花期比两性花的早10-15d,但二者的花期同时结束;雄性花花粉的萌发率最高为97.8%,而两性花的花粉不能萌发,雄花的花粉为三孔沟有萌发孔,而两性花的花粉为球形无萌发孔;36种访花昆虫中,只有蜂类和蝇类4种昆虫为有效传粉者;存在风媒,但以虫媒为主;两性花自花授粉和异花授粉均不结果实,用雄花花粉给两性花人工授粉的结实率为47%;两个野外居群的性别比例分别为1:1.7和1:2,性比偏雌;但在居群水平上花的性别比例偏雄。由此可知:云南蓝果树是形态上的雄性两性异株,功能上的雌雄异株植物。异交繁殖,性别比例失衡于1:1,都可能是导致该种濒危的原因。 8.云南蓝果树的保护遗传学研究 通过ISSR分子标记手段,分别比较分析了居群间父代、居群内父代与子代间的遗传多样性,结果表明云南蓝果树的遗传多样性水平较高;除水井居群外,其他居群内的子代的遗传多样水平都高于其父代。 保护措施:首先要加强政府宣传,就地保护;通过人工繁育的引种驯化手段增加居群个体数量,然后引种回归。
其他摘要Nyssa L. is a remnant genus of Nyssaceae with the disjunct distibutional patterns between eastern Asia and North America. There are seven species in China (five endemic) according to Flora of China. A revision of Nyssa was proposed based on observation in the field, studying specimens, analyzing morphological characters and molecular phylogeny. The results revealed that N. yunnanensis W. C. Yin ex H. N. Qin & Phengklai was a distinct taxon. Besides, wild investigation, cytology, pollination ecology and conservation genetics have been studied on this species. The causes of critically endangered species of N. yunnanensis were discussed, and correspondent conservation strategies also were proposed according to the above-mentioned. The main results are summarized as follows: 1.Morphology Thirty-three qualitative characters and 19 quantitative characters of Nyssa in China were analysed via statistics and principle component analysis (PCA). The results showed that N. yunanensis was a distinct taxon and different from N. javanica (Bl.) Wanger. N. sinensis Oliv., N. shweliensis (W. W. Smith) Airy-Shaw, N. shangszeensis Fang et Soong and N. wenshanensis Fang et Soong were not distinct. N. leptophylla Fang et Chen was excepted because there were no information about its collecter and site on its type specimen. 2.Molecular phylogeny Camptotheca acuminate Decne.and Davidia involucrata Baill were choosed as outgroup. Two species, N. sylvatica Marsh and N. aquatica L from North America, were also treated as ingroup, excepting those species of Nyssa in China. Phylogeny of Nyssa was studied by maximum parsimony analysis of nuclear ribosomal ITS and 5 chloroplast psbA-trnH, rps16r-f, trnL-F, trnL-rps32F, trnsr-sf gene sequence, respectively or unitedly. The results were same as that of morphology. N. yunnanensis was a distinct and basal taxon and affinities with N. javanica. N. sinensis, N. shwenliensis, N. shangzeensis and N. wenshanensis clustered togeter, and they were affinities with N. sylvatica. 3.Taxonomic revision of Nyssa in China Combining the results of morphology and molecular phynology, we made the classification revision of Nyssa and concluded three species N. yunnanensis, N. javanica and N. sinensis distributing in China. N. leptophylla Fang et Chen were numerated as dubious taxa. 4.Biological traits of N. yunnanensis, a critically endangered species N. yunnanensis is a canopy tree narrowly distributed species of nortern edge in tropical zone with 37 individual in the two wild populations. It grows nearby stream with conifer and broadleaf with poor natral regeneration. It was morphologically androdioecy. 5.Seed germination traits of N. yunnanensis Seed morphology was observed and effects of substance types, light, destroying the endocarp artificially and gradient pH on germination percentage of the species, N. yunnanensis, were investigated primarily. The results showed that the average seed size with endocarp was 0.94cm×0.52cm×0.17cm (length×width×thickness), per- thousand-seed-weight about 234.3g, with germination valve. Among the three substance types, laterite/ humus soil/ peat (v/v/v, 1:1:1) was better for N. yunnanensis. Seeds could germinate in the both light and dark, the germination rate be increased by destroying the endocarp artificially obviously, and the seed germination of N. yunnanensis was stunted by treaded in lye, however, that of N. sinensis was promoted. Besides, the rarity causes of N. yunnanensis were discussed in this paper. 6.Cytology of N. yunnanensis Chromosome numbers, 2n=44, of N.yunnanensis was investigated and reported here for the first time. It was same as other species of Nyssa but different in existing B-chromosome in this species which might be related to its ratity. 7.Pollination ecology of N. yunnanensis We herein documented the flower phenology, pollen germination and morphology, sex ratio, pollinators, and mating system of N. yunnanensis. The results showed that the male flowers opened 10-15 days earlier than hermaphrodites, but ended at nearly the same time. The mean germination rate for pollen from males on the sucrose gradient solution was 97.8%, whereas that from hermaphrodites was 0%. Pollen morphology of males was tricolporate but that of hermaphrodite inaperturate. Thirty-six species of visitors to the flowers were collected, and four of them including bees and flies were the effective pollinators. Anemophilous and entomophilous pollination co-existed in N. yunnanensis, with the latter dominated the breeding system. The mating system was xenogamous and parthenogenesis was not detected. No seeds were produced in inflorescences with self-pollination or in those self-pollinated by pollen from hermaphrodites. In contrast, the mean seed set of male-pollinated inflorescences was 47%. The sex ratio of males: hermaphrodites in the two populations examined were 1:1.7 and 1:2, respectively, female-biased. Yet the flower sex ratio was 2.56:1, which was male-biased. These results indicate that N. yunnanensis is functionally dioecious. Strong xenogamy and biased sex ratio might be the reasons why it is so rare. 8.Conservation genetics of N. yunnanensis ISSR markers were used to determine the genetic variation among different populations and between parents and progeny in different populations of N. yunnanensis. High genetic diversity of N. yunnanensis was detected. Except Well population, genetic diversity of progeny was higher than their parents in others. In order to protect the critically endangered tree, some strategies should be recommended: reinforcement of public education and in-situ conservation, introduction by collecting seed to increase the number of individuals, and then reintroduction.
页数114
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/380
专题昆明植物所硕博研究生毕业学位论文
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孙宝玲. 中国蓝果树属分类学与极度濒危植物云南蓝果树保护生物学[D]. 昆明植物研究所. 中国科学院昆明植物研究所,2008.
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