稀有植物屏边开口箭的保护生物学研究
乔琴
学位类型博士
导师张长芹
2010-01
学位授予单位中国科学院研究生院
学位专业植物学
摘要屏边开口箭(Tupistra pingbianensis Huang et Liu)隶属于百合科(Liliaceae)长柱开口箭属(TupistraKer Gawler),是中国特有种,仅分布在滇东南的悬崖峭壁上以及原始森林树干上。由于其生境特殊,分布范围狭窄,居群数目有限,屏边开口箭直到1996年才作为该属的新种被发现,并被《中国物种红色名录》列为极度濒危植物。作为分布在特殊生境中的一种稀有植物,屏边开口箭为保护生物学的研究提出了新的研究思路。本文通过对其生物学特性、种群结构特征、种子萌发特点、细胞学、繁殖生态学、保护遗传学等方面较为全面系统的研究,为稀有植物屏边开口箭濒危状况、稀有的内在机理、引种驯化积累了必要的基础生物学知识。1、生物学特性: 屏边开口箭为多年生草本植物,植株片丛状生长,兼有有性、无性繁殖方式,种子主要靠重力传播。花期11月-12月,果期在翌年的11-12月。在野外共发现屏边开口箭11个居群,大多生长在滇东南地区的石灰岩崖壁和原始森林高大的树干上,居群中个体数较少且生境极为特殊。2、种子特性及萌发研究:通过播种和栽培试验初步研究了萌发基质、播种深度以及光照对屏边开口箭种子萌发的影响,结果表明:屏边开口箭种子百粒重为35.03±0.12g,种子平均大小为(1.17±0.02)cm×(0.79±0.01)cm×(0.77±0.01)cm(长度×宽度×厚度);适宜在少量覆土的条件下萌发;碱性土壤是屏边开口箭萌发较为理想的基质;光照不仅能够提高萌发率,而且加速屏边开口箭种子的发芽进程。野外或适宜条件下较高的萌发率也许是屏边开口箭为了适应环境而产生的生态对策。3、核型与进化研究:共选取开口箭属(Campylandra Baker)、长柱开口箭属(Tupistra Ker Gawler)以及蜘蛛抱蛋属(Aspidistra Ker Gawler)共8种植物进行染色体观察及核型分析,其中两种为首次报道。与前人研究结果一致,鉴于长柱开口箭属植物核型和花式的二重性,我们认为具二型性核型的长柱开口箭属植物是开口箭属向蜘蛛抱蛋属演化的一个过渡类型。而与该属其他植物相比,亲缘关系较近的屏边开口箭和伞柱开口箭极不对称的染色体核型,说明二者核型演化地位较高。4、繁育生态学研究:通过对屏边开口箭的开花物候、传粉生物学、交配系统的研究以及对近交衰退的检测,结果显示:屏边开口箭单花花期约15天左右,柱头、花粉活力持续时间较长;传粉昆虫多为蚂蚁、跳虫,偶有小甲虫拜访,缺乏长距离传粉昆虫;杂交指数(OCI)以及套袋试验的结果表明屏边开口箭为高度自交亲和的混交模式植物,且在幼苗早期并没有表现出明显的近交衰退现象。为了适应长期在特殊生境下的衍生,屏边开口箭的繁育系统似乎在向折中的混和交配系统方向演化,并通过遗传负荷的淘汰以减少近交衰退的影响,从而保持了其种群的繁衍能力。5、保护遗传学研究:采用AFLP分子标记技术对收集到的来自11个居群的97份材料进行了遗传学特征研究,结果显示屏边开口箭具有较高的遗传多样性(P99 = 96.012%; Ht = 0.302),且居群间存在着较大的遗传分化(⍬II=0.281,Fst=0.296)。其特殊的生境以及其生活史特性对于维持较高的遗传多样性有着重要作用,而基因流受阻和遗传漂变可能是导致屏边开口箭居群间产生较大遗传分化的主要原因。建议在对稀有植物屏边开口箭的就地保护过程中,应加强对生境以及每个居群的保护
资助项目Tupistra pingbianensis J. L. Huang & X. Z. Liu, is a newly described perennial herb narrowly distributed in South-east Yunnan, China. It belongs to genera Tupistra Ker Gawler(Liliaceae). It usually occurs on outcrops of bare rock, or occasionally as an epiphyte on tree trunks covered with humus and moss. T. pingbianensis is unusual in that it exhibits rarity according to three different ways of measuring rarity, i.e. it has a small geographical range, is a habitat specialist, and always has low abundance where it occurs. Because of this, T. pingbianensis has been listed as an endangered species and catalogued in the Chinese Species Red List. In order to discuss the causes of rarity of T. pingbianensis, the multidisciplinary investigations of the seed and seedling establishment, cytology, breeding system, and population genetic structure of the endangered T. pingbianensis were performed in this thesis. Besides, the corresponding conservation strategies were also proposed according to the above-mentioned. The main results are summarized as follows:1. Biological traits of T. pingbianensis,T. pingbianensis is a perennial herbaceous with a creeping rhizome, thick basal leaves, and an inflorescence that is a terminal spike. Florescence is from November to December, while fruiting occurs between November and December in the next year. Reproduction and spread also occurs clonally via rhizomes, most seeds simply fall from the mother plant and germinate where they land. It occurs on outcrops of bare rock, or occasionally as an epiphyte on tree trunks covered with humus and moss, which are naturally rare habitat. Throughout its small geographical range, T. pingbianensis occurs as discrete, small populations size. 2. Seed germination traits of T. pingbianensis,Seed morphology was observed and effects of substrates soil types, light, sowing depth on germination percentage of the species T. pingbianensis were investigated primarily. The results showed that the average seed size was (1.17±0.02) cm × (0.79±0.01) cm × (0.77±0.01) cm (length × width × thickness), per-hundred-seed-weight was about 35.03±0.12g. Among the three different substrates soil types and sowing depths, seeds of T. pingbianensis germinate best in alkalescence soil and shallow sowing depth (2cm). It could germinate in the both light and dark, but the germination rate can be accelerated by light obviously. Its seed has high germination rate not just in greenhouse, but also in the field. We considered that this is a good strategy to expand its population in the special habit.3. Karyotype evolution status of T. pingbianensis,The karyotype of total eight species in Campylandra, Tupistra and Aspidistra from China were reported. Considering Tupistra has the similar morphological character with Campylandra but resemble Aspidistra in karyotype. The results support the earlier study that Tupistra is a transition between Compylandra and Aspidistra. Besides, our results also showes that the T. pingbianensis and T. fungilliformis has higher karyotype asymmetry than other species in this genera, which means these species have higher karyotype evolution status. 4. Reproduction ecology of T. pingbianensis, The flower phenology, pollinators of T. pingbianensis were documented herein. We also examined the breeding system of T. pingbianensis and seed fitness traits to determine what forms of pollination and mating occur in this naturally rare species, and is there evidence of inbreeding depression in its populations. The results shows that the flowers opened 10-15 days, which suggest stigma and pollen can keep high vitality for a long time (10-15 days). The only pollinators observed on T. pingbianensis flowers were ants (Aphaenogaster smythiesii Forel,Formicidea), springtail (Hypogastrura sp., Hypogastruridae, Collembola) and one species of beetles (Anomala corpulenta Motsch, Rutelidae). These pollinators generally have restricted movement capacities and hence promote geitonogamy or mating between individuals in close proximity within populations. The results of out crossing index (OCI) pollination experiments in our study suggest that T. pingbianensis has an animal-pollinated, mixed selfing and outcrossing breeding systems. However, a pollination experiment also fail to detect significant inbreeding depression upon F1 fruit set, seed weight and germinate rate fitness-traits. Since naturally rare species T. pingbianensis is not seriously genetically impoverished and likely to have adapted to tolerating a high level of inbreeding early in its history. 5. Conservation genetic of T. pingbianensis, The levels and partitioning of genetic diversity were investigated in Tupistra pingbianensis. Here genetic diversity and patterns of genetic variation within and among 11 populations were analyzed using AFLP markers with 97 individuals across its whole geographical range. High levels of genetic variation were revealed both at the species level (P99 = 96.012%; Ht = 0.302) and at the population level (P99 = 51.41%; Hs = 0.224). Strong genetic differentiation among populations was also detected (FST = 0.2961; ⍬Ⅱ= 0.281), which corresponded to results reported for typical animal-pollinated, mixed selfing and outcrossing plant species. Special habitat and its life history traits may play an important role in shaping the genetic diversity and the genetic structure of this species. Based on the special habitat in T. pingbianensis, the most suitable strategy for its conservation is the protection of its habitat. Moreover, given the observed strong genetic differentiation among populations of T. pingbianensis, the preservation of genetic diversity in this species will require the protection of many populations as possible to maintain the current levels of genetic variability.
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16156
专题昆明植物所硕博研究生毕业学位论文
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乔琴. 稀有植物屏边开口箭的保护生物学研究[D]. 中国科学院研究生院,2010.
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