广西滨海红鳞蒲桃群落天然更新的影响机制

Syzygium hancei is the main constructive tree species of north tropical seasonal rain forest and its community is the important composition part of coastal vegetation in south Guangxi. It palys an important role in ecological environment construction of Beibuwang gulf. As the intense human activities impacts, habitats fragmentation is serious in S. hancei communities and forest degraded and the biodiversity reduced. Based on the previous investigation and research, it has been found that seed germination and seedling growth required strictly habitat conditions and finally result in the communities are experiencing difficulties in natural regeneration. In order to find out the characteristics of natural regeneration of S. hancei communities and its enviornmental influence mechanism, the study intends to survey the communities structure and monitor the variation of environmental factors. Moreover, the experiment, which involves seeds collection and germination, seedlings cultivation and growth, are carried out under control conditions. The physiological and biochemical indexes, morphological and anatomical structure under different light densities, water supply and salt contents will be compared and analyzed in different growth periods of seed germination and seedlings growth. The purpose of this study is to find out the stress resistance and the relationship between environment factors and natural regeneration of S. hancei. And, the results would be providing scientific basis for the research, conservation and restoration of S. hancei and even that of coastal natural vegetation in southern China.

红鳞蒲桃是广西滨海北热带季节性雨林的主要组成树种和构建海岸植被的重要组成群落，在北部湾生态环境建设中具有重要的作用。由于受到强烈的人为活动干扰，红鳞蒲桃群落的生境破碎化严重，林分退化、生物多样性减少。从前期的调查及研究发现，红鳞蒲桃的种子萌发及苗木生长对生境的要求非常严格，天然更新困难，为了阐明红鳞蒲桃天然更新的特征及环境影响机制，本研究拟通过调查群落结构、测定环境因子的变化，并收集种子进行萌发试验，培育苗木开展人工控制条件下的盆栽生长试验，比较和分析在不同光照、水分、盐分条件下红鳞蒲桃种子的萌发特性和苗木生长不同发育阶段的生理生化指标和形态解剖特征，探索红鳞蒲桃的抗逆性以及与环境条件的相互关系，研究成果将为红鳞蒲桃群落乃至华南滨海地区天然植被的研究、保护和恢复提供科学的依据。

红鳞蒲桃是广西滨海北热带季节性雨林的主要组成树种和构建海岸植被的重要组成群落，在北部湾生态环境建设中具有重要的作用。由于受到强烈的人为活动干扰，红鳞蒲桃群落的生境破碎化严重，林分退化、生物多样性减少。为了阐明红鳞蒲桃天然更新的特征及环境影响机制，本研究通过调查群落结构和环境因子，培育苗木开展人工控制条件下的盆栽生长试验，比较和分析在不同光照、水分、盐分条件下红鳞蒲桃苗木的生长、生理生化指标和形态解剖特征，探索红鳞蒲桃的抗逆性以及与环境条件的相互关系。. 结果表明：（1）红鳞蒲桃群落物种组成较为丰富，草本层的物种较少；（2）群落土壤持水能力差，养分较为贫瘠；（3）红鳞蒲桃苗木在更新初期对光照要求较高，1年生和3年生苗木在全光照下的表现要优于其它遮阴处理。（4）干旱和盐胁迫都抑制了红鳞蒲桃的生长，盐胁迫的影响要大于干旱胁迫，充足的水分供应可缓解盐胁迫对红鳞蒲桃的影响。（5）遮荫干旱交互胁迫对红鳞蒲桃幼苗的影响十分显著，光照对苗木生长和生理特征的影响要大于水分的影响，幼苗在轻度遮荫下仍可正常生长。（6）红鳞蒲桃叶片具有较强的光可塑性，在强光下，红鳞蒲桃幼苗叶片为阳生叶特征，在弱光照条件下，叶片为阴生叶特征。. 研究结果可以基本确定影响红鳞蒲桃自然更新的主要因素是光照和水分，林内光照不足，林外水分缺乏是影响红鳞蒲桃自然更新成功的重要原因。研究成果将为红鳞蒲桃群落乃至华南滨海地区天然植被的研究、保护和恢复提供科学的依据。