鄱阳湖湿地植物繁殖库对水文情势变化的响应

The role of plant propagule bank(seed and bud banks) in the establishment, succession and restoration of wetland vegetation has always been concerned in wetland science. Research on the responses of strategy and mechanism of plant propagule bank to water level changes is the hot issue in the field of ecology. Wetland of Poyang Lake with high fluctuation in water level will be chosen as research object in this work. The field survey and laboratory simulation research will be carried out in the composition, size and distribution of plant propagule bank, through selecting six transects along water gradient in three different soil deposition zones of Poyang Lake, to clarify the response strategy of plant propagation to water fluctuation and the complementary effects of seed and bud, to further explore the response mechanism from enzymes of seed and bud. The goals of this work are as follows (1) understand the response strategy of wetland plant propagule bank to water fluctuation, promoting the development of wetland science. (2) forecast the response of vegetation to water-level changes, providing practical evidence and theoretical basis to answer hydrological process, eco-system structure and the correlation of ecological process and functions.

植物繁殖库(种子库、芽库)在湿地植被建立、演替、恢复中的作用一直受到湿地科学研究的关注，而其对水位变化的响应对策与响应机制是生态学领域有待剖析的热点问题。本研究选取水位高变幅的鄱阳湖湿地为研究对象，以近年来面临水位波动过程发生变化的环境问题为切入点，针对湿地植物繁殖库对水位过程变化响应规律认识的局限性，结合湖泊管理的需求，在鄱阳湖三种不同土壤沉积类型区，沿水位梯度选取6条样带，开展土壤繁殖库组成、规模、沿水位梯度的分布，不同水位过程下萌发响应的原位监测和实验室模拟研究，阐明繁殖库的响应策略，种子和芽的互补效应，并从种子、芽的酶活性变化等生理生态角度探讨其响应机制。一方面有助于了解高变幅湖泊湿地繁殖库对水位过程发生变化的响应策略，促进湿地科学的发展；另一方面，可以预测湿地植被对水位变化的响应，为回答水文过程变化、生态系统结构、生态过程与功能之间的关联性提供实践证据和决策参考。

植物繁殖库(种子库、芽库)在湿地植被建立、演替、恢复中的发挥重要作用，而其对水位变化的响应对策与响应机制是湿地生态学的关键问题和热点问题。本研究在鄱阳湖三种不同土壤沉积类型区，沿水位梯度选取9条样带，开展土壤繁殖库组成、规模、沿水位梯度的分布，不同水位过程下萌发响应的模拟研究。结果表明：（1）土壤种子库有20科36属49种植物，种子库密度为17328.6±1675.3粒/m2，主要分布于表层5cm。芽库植物有6科12属16种，密度为798.0±73.5个/m2。（2）春季土壤种子库萌发物种数多于冬季，分别为38种和29种；其种子密度无显著差异，春季为7715±1404.11粒/m2，冬季为7453±1188.59粒/m2。（3）土壤种子库与地表植被的关系较弱，相似性介于17%与39%之间；芽库与地表植被的关系稍密切，相似性介于20%与67%之间。（4）繁殖库通过萌发不同的物种组合，形成不同响应策略应对水情变化，不同的淹露节律和不同的水文周期会影响湿地植物繁殖库的生长和萌发，尤其是水位升高至2m时，沉水植物大量繁殖，且中水位区具有演变成沉水植物群落的潜在可能。本研究结果有助于了解高变幅湖泊湿地繁殖库对水位过程发生变化的响应策略，以及预测湿地植被对水位变化的响应，可湿地生态学和湿地管理提供理论指导。