中国特有植物大树杜鹃的濒危机制与种群保育策略实验研究

Endemic and endangered species has generally been accepted as a priority for conservation, and its endangered mechanism and conservation strategies have been recognised as a global concern in the biodiversity conservation. Rhododendron protistum var. giganteum is an endangered plant of the family Ericaceae that is endemic to China. The plant is restricted to one remnant population with few individuals in the Gaoligongshan National Nature Reserve of Yunnan Province. Although this plant has been list as a critically endangered plant according to the criteria of the International Union for Conservation of Nature (IUCN), almost nothing is reported regarding its conservation biology. This program, based on our preliminary research about its distribution, surviving status and some biological characteristics, is to study the endangered mechanism of Rhododendron protistum var. giganteum and put forward strategies for its conservation. Its endangered status will be assessed based on the field population and community ecology survey. Furthermore, the limiting factors for natural regeneration of the species will be studied using field experiments about seeds dispersal, seedling emergency and establishment. Its reproductive biology will also be studied through field flowering phonological observation, pollination biology and breeding system test. Its genetic diversity and population structure will be assessed using simple sequence repeats (SSR) molecular marker. Furthermore, the artificial propagation of Rhododendron protistum var. giganteum will be studied through experiments of seed biology and germination ecophysiology, seedling propagation and mycorrhizal fungi inoculation. Based on these results, we will elucidate the endangered mechanism and provide a viable artificial propagation technology of this plant and consequently develop scientific and feasible strategies for its conservation. This project will not only provide scientifical basis for the conservation and population recovery of Rhododendron protistum var. giganteum, but also provide important theoretical and practical reference for the population conservation of other endemic and endangered plants.

特有濒危植物作为生物多样性的优先保护类群，其濒危机制与种群保育策略研究一直是保护生物学关注的焦点。本项目以杜鹃花科中国特有濒危植物大树杜鹃的种群保护为目标，通过种群与群落生态学调查、种子散布、种子萌发与幼苗库建成等自然更新试验研究，探明物种的濒危现状及种群自然更新的限制因子；基于花部综合特征观测、传粉生物学试验和繁育系统检测，研究大树杜鹃的繁殖生物学特性；利用微卫星（SSR）分子标记研究物种的遗传多样性与遗传结构，综合分析并阐明该物种的濒危机制。在此基础上，通过种子生理生态、幼苗繁育及菌根真菌分离与接种试验研究，构建大树杜鹃的人工繁殖体系，提出大树杜鹃科学、可行的人工繁殖技术与种群保育策略，最终使该濒危物种的种质资源得以最佳保护和延续。项目研究将为该濒危植物的保护和种群复壮提供科学依据和可行性方案，并对其它特有濒危植物的保育和种群恢复具有重要参考价值。

本项目自2014年-2017年实施四年以来，通过对大树杜鹃的自然分布、种群和群落特征、生境和繁殖生物学的野外调查、观测与研究，结合室内种子生理生态、内生真菌分离、扩繁与接种、幼苗建成以及遗传结构与变异等方面研究了大树杜鹃的濒危现状、濒危机制与人工繁育技术与方法。提出了该物种科学、可行的人工繁殖技术与种群保育策略。项目整体按照原计划顺利完成研究内容并达到研究目标，取得的研究成果如下：（1）探明了大树杜鹃在高黎贡山国家级自然保护区的分布现状，种群结构特征分析表明大树杜鹃种群存活曲线趋于Deevey-Ⅲ型，总体处于衰退趋势；（2）大树杜鹃种子没有休眠，温度对种子萌发率影响显著；黑暗显著抑制种子的萌发，即大树杜鹃种子萌发对光照敏感，为需光性种子；立地条件影响大树杜鹃从种子萌发和幼苗建成；（3）AFLP和SSR分子标记研究表明，大树杜鹃在物种水平上具有较高遗传多样性，遗传变异主要存在于居群内，研究结果支持狭域分布的小种群亦能维持较高的遗传多样性的假说。大树杜鹃具有较高的历史基因流和较低的近代基因流，其有效居群大小都低于30，表明其不能维持足够的等位基因丰富度，处于极危状态。（4）从大树杜鹃两个居群的根段中分离出287个生长缓慢的菌株，完成了其形态与分子鉴定、接种试验；（5）获得了大树杜鹃的人工繁殖技术与方法，并在此基础上成功繁育了大树杜鹃的种子实生苗；（6）基于上述研究工作，提出了加强残存种群的就地保护、不同种源种子采集进行幼苗人工繁育，并在此基础上开展大树杜鹃的种群恢复与回归自然的保护策略与建议。项目共发表研究论文9篇（其中已发表SCI 3篇，发表中文核心期刊论文4篇，会议论文2篇），授权国家发明专利1项，参加国内外学术会议与交流3次，共同培养博士和硕士研究生共2 人（均答辩获相应学位），项目主持人晋升副教授职称，并入选云南省中青年学术与技术带头人后备人才计划。