滇西北高原典型湿地湖滨带植物物候、生长与繁殖对增温的响应

The impacts of cliamte change, characterized by increasing temperatures, on wetland ecosystems have presently attracted widespread scientific attention.Wetlands in the Northwestern Yunnan Plateau, a unique type of closed and semi-closed wetland across the world, have the important functions of long been valued for the provision of resources and environment services, however been threatened due to the extreme sensitivity of these fragile ecosystems to the climate change.To date the responses and adaptions of plateau wetland ecosystems to climate change are still poorly understood, while such information could provide useful insight into wetland protection in our country and promote honoring an agreement on wetland convention under global warming. Given this, we therefore, propose a case study addressing this issue at Napahai, a wetland of international importance located at the Northwestern Yunnan Plateau, where three dominant speciese Scirpus tabernaemontani, Hippuris vulgaris and Sparganium stoloniferum will be choosen as key study objects. Since these lakeside plant communities are the basis of wetland structure and functions, in this project, two temperature gradients will be set based on the warming scenarios IPCC forecasted, and the "Open-top Chamber + carbon infrared emission warming system" will be employed to conduct the location position warming control experiments. We aim to detect the responses of (1) the pheonological characteristics,(2)growth and (3) sexual reproduction of these dominant lakeside plant species and ,populations to elevated temperatures as well as their adaptations (e.g. adaptive strategies);and thus to establish a database with this information, which would generate knowledge on the reponsive and adaptive characteristics of lakeside plant dominant species and population's phenonlogy, growth and reproduction, as well as their their similar or divergent rules and mechanisms for plateau wetlands in response to global climate warming; Moreover, it could contribute to revealing the approaches and patterns that climate change impacts on the lakeside plants and ecosystems at the plateau wetlands,meanwhile, provide sound information and theories for the related scientific assessment and plateau wetland conservation under climate change.

气候变化对湿地的影响是国内外关注的热点，但湿地生态系统对气候变化响应与适应机制的研究尚缺乏。针对气候变化国际研究热点、以及国家对湿地保护和湿地履约的重大需求，基于温度升高这一气候变化的主要特征，选择滇西北高原封闭与半封闭独特湿地类型纳帕海为研究对象，以其结构与功能核心- - 湖滨带植物群落优势种为研究切入点，依据IPCC对气候变暖预测设置增温梯度，通过"OTC+碳素红外线辐射增温系统"对湖滨带植物优势种移栽个体和原位优势种群进行增温控制实验，研究其物候、生长和繁殖对增温响应的生态过程，建立湖滨带植物优势种个体、种群的物候、生长和繁殖对增温响应参数的数据库，掌握湖滨带优势植物物候、生长与繁殖对气候变暖的响应与适应特征，以及湖滨带优势植物物候、生长和繁殖对气候变暖的趋同或趋异响应规律及其机制，探讨气候变化对高原湿地生态系统的影响途径及其作用规律，为应对气候变化、加强高原湿地的生态保护提供理论依据。

针对气候变化国际研究热点、以及国家对湿地保护和湿地履约的重大需求，基于温度升高这一气候变化的主要特征，选择滇西北高原湿地湖滨带植物群落优势种为研究切入点，通过构建原位开顶室增温系统（OTCs），设置两种目标增温（环境增温（2.0±0.5）℃（EW-I），环境增温（3.5±0.5）oC（EW-II）），选取滇西北高原纳帕海湿地湖滨带优势植物茭草（Zizania latifolia）（ZL），杉叶藻（Hippuris vulgaris）（HV），黑三棱（Sparganium stoloniferum）（SS）和水葱（Scirpus tabernaemontani）（ST），通过克隆单株盆栽实验，研究高原湿地湖滨带优势植物（1）叶、花及果物候，（2）光合作用（光呼吸、光响应、CO2响应），克隆生长（生物量及生物量分配），以及（3）有性繁殖（开花结实率、穗特征、种子形态、产量）对两种大气增温的响应特征及规律。同时，整合分析OTCs平均增温目标下，温度因子的变化规律（平均温、最高温、最低温，日温差），研究不同温度因子与湿地植物物候、光合作用、克隆生长、有性繁殖的相互关系，以揭示气候变化对湿地植物影响的作用途径及机制。研究结果表明：（1）大气增温改变湿地植物的叶、花和果物候期，有缩短湿地植物生长期的趋势；（2）湿地植物光合作用在增温前期为趋异响应，而到第三年增温处理下为趋同响应，增温对湿地植物光合作用参数具有明显的抑制作用。各温度因子对植物光合作用参数的影响及解释度不同。（3）湿地植物克隆生长，尤其是地下芽的生长、生物量、及生物量分配对增温的响应存在趋同响应和趋异响应，其中，增温处理前期，为趋同，增温处理后期为趋异，日温差天数比例的变化是影响湿地植物地下芽生长、生物量分配的关键因子。（4）大气增温增强了湿地植物的有性繁殖投入，改变了开花结实率、穗的特征，以及种子形态与产量。研究掌握了4种湖滨带植物物候、生长和繁殖对增温响应参数的数据，掌握了湖滨带优势植物物候、生长与繁殖对气候变暖的响应与适应特征，趋同或趋异响应规律及其机制。