克隆多样性对竹林群落稳定性的影响机制

Clonal plants widely exist in almost all types of ecosystem. And the clonal traits and their community level effects has become the research hotspots.Genotype or strain diversity within populations of ramets of clonal plants known as clonal diversity in clonal plants dominant with communities, the clonal diversity may significantly affect the community and even ecosystem structure and function. F. robusta and P. bissetii, which often format its single dominant excellent community by clonal reproduction, were selected as materials in this project.By the method of transplanting, the F. robusta and P. bissetii experimental communities were builded, and combined with the simulation of the giant panda chomping on interference processing, structure (communities of the dominant species / species population dynamics of the F. robusta and P. bissetii communities) and function (community productivity ) comprehensive analysis of clonal diversity and community stability, and to reveal the mechanism of clonal diversity on the stability of the giant panda staple food bamboo single excellent community. This study provides direct experimental evidence to investigate the genetic (genotype) diversity, ecological effects, for promoting the understanding of the relationship between biodiversity and ecosystem significance. At the same time enriched and developed the clonal plant ecology, and community level has important practical significance for improving and upgrading the level and capacity of China's giant panda conservation.

森林群落稳定性一直是森林培育学者关注的重点内容。群落稳定性与生物多样性密切相关。但现有研究多集中于群落稳定性与物种多样性，有关基因型（遗传）多样性与群落稳定性的关系尚缺乏实验证据。在克隆植物居优势的群落中，克隆多样性可能显著影响群落乃至生态系统的结构与功能。本项目通过分别构建拐棍竹、白夹竹单优实验群落，结合模拟大熊猫咬食干扰处理，从结构（群落中优势种／建群种拐棍竹的种群动态）和功能（群落生产力）综合分析克隆多样性与群落稳定性的相关性，揭示克隆多样性对白夹竹、拐棍竹单优群落稳定性的影响机制。本研究为探讨遗传（基因型）多样性在群落稳定性方面的生态效应提供了直接实验证据，对于推进生物多样性与生态系统关系的认识具有重要意义。同时丰富和发展了群落水平上克隆生态学理论，对于改善、提升我国大熊猫保护水平和能力具有重要现实意义。

竹类植物是大熊猫的主要食物来源，竹林群落结构与功能的稳定对维持大熊猫生存和种群繁衍至关重要。植物群落稳定性与生物多样性密切相关。现有研究集中于物种多样性层次，有关基因型（遗传）多样性与群落结构与功能稳定性的关系不清楚，存在诸多争议。项目以大熊猫主食竹——白夹竹、冷箭竹为研究对象，通过利用AFLP分子标记技术对卧龙国家自然保护区不同基株年龄的冷箭竹竹林群落的遗传多样性和克隆结构及其与种群演替（发育）阶段的关系进行分析研究；采用移栽构建白夹竹实验群落方法，结合模拟干扰处理，研究克隆多样性与结构和功能的相关性，揭示克隆多样性对竹林单优群落稳定性的影响机制。结果发现，1）克隆繁殖的2个不同林龄的冷箭竹种群均为多基因型构成，基因型个数在种群间分布不均，种群具有很高的克隆多样性；2）克隆生长特征促进了遮荫白夹竹分株根际土壤的C有效性和微生物生物量，进而影响到了根际土壤生物过程；并且同化产物的传输方向（顶向，基向）对遮荫分株根际氮素转化过程有着不同影响，同时遮荫分株根际土壤功能基因丰度的变化以及功能菌群在土壤的微弱比例可能某种程度上解释了根际土壤微生物群落并没有受到克隆整合作用的现象；3）克隆整合作用影响处于遮荫环境的白夹竹远端分株的光合氮分配格局，使得处于逆境中的克隆分株依旧维持较高的光合能力，保证了处于逆境条件下克隆分株的生存与生长。研究为探讨基因型（遗传）多样性在群落稳定性方面的生态效应提供直接实验证据，对于提高生物多样性与生态系统关系的认识，改善、提升我国大熊猫保护水平具有重要现实意义。