屏边开口箭（Tupistra pingbianensis Huang et Liu）隶属于百合科（Liliaceae）长柱开口箭属（Tupistra Ker 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，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。
自2005年起，中国科学院昆明植物研究所张长芹研究员带领的研究组，在国家科技部平台项目和云南省重点新产品计划项目的资助下，对屏边开口箭进行了野外调查、开花物候、传粉生物学和交配系统的研究以及对近交衰退的检测以及保护遗传学研究。
研究共发现屏边开口箭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。花期时间为11月-12月，果期在翌年的11月-12月。兼有有性、无性两种繁殖方式，种子主要靠重力传播；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；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；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）。其特殊的生长环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。
该项研究不仅加深了对屏边开口箭的了解，而且探讨了其稀有的原因，提出了对屏边开口箭的保护建议，培养毕业博士生1名。项目成果已发表于2010年的《植物分类学报》（Journal of Systematics and Evolution）。
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《植物分类学报》发表论文摘要（英文）
Journal of Systematics and Evolution
Volume 48 Issue 1, Pages 47－57.
Published Online: 18 Jan. 2010
DOI: 10.1111/j.1759-6831.2009.00064.x
Population genetics and breeding system of Tupistra pingbianensis (Liliaceae), a naturally rare plant endemic to SW China
1,2Qin QIAO 1Chang-Qin ZHANG* 3Richard Ian MILNE
1(Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China)
2(Graduate School of Chinese Academy of Sciences, Beijing 100049, China)
3(Division of Environmental and Evolutionary Biology, School of Biology, University of St. Andrews, St. Andrews, Fife KY16 9TH, UK)
Keywords: AFLP, genetic diversity, genetic structure, inbreeding depression, naturally rare plants, Tupistra pingbianensis.
Abstract:
The levels and partitioning of genetic diversity and inbreeding depression were investigated in Tupistra pingbianensis, a narrow endemic of South-east Yunnan, China, characterized by a naturally fragmented distribution due to extreme specialization on a rare habitat type. 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; l嘦= 0.281), which corresponded to results reported for typical animal-pollinated, mixed selfing and outcrossing plant species. This result was consistent with mating patterns detected by our pollination experiments. The indirect estimate of gene flow based on l嘦 was low (Nm = 0.64). Special habitat and its life history traits may play an important role in shaping the genetic diversity and the genetic structure of this species. 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, we propose this species need only periodic monitoring to ensure their continued persistence but not intervention to remain viable.
