石灰岩地区连片出露石丛生境植物水分来源的季节性差异  

Seasonal variation of water sources for plants growing on continuous rock outcrops in limestone area of Southwest China

作　　者：聂云鹏[1,2,3] 陈洪松[1,2] 王克林[1,2] 

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院环江喀斯特生态系统观测研究站,广西环江547200 [3]中国科学院研究生院,北京100049

出　　处：《植物生态学报》2011年第10期1029-1037,共9页Chinese Journal of Plant Ecology

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-QN404);中国科学院西部行动计划项目(KZCX2-XB2-08);国家自然科学基金项目(405-01034)资助

摘　　要：以桂西北石灰岩地区连片出露石丛生境次生林群落为研究对象,运用稳定性氢氧同位素技术结合IsoSource模型,分析了5种典型植物(半落叶乔木粉苹婆(Sterculia euosma)、落叶乔木菜豆树(Radermachera sinica)、常绿灌木鹅掌柴(Scheffleraoctophylla)以及落叶灌木红背山麻杆(Alchornea trewioides)和紫弹树(Celtis biondii))水分来源的季节性差异。结果表明:雨季,除鹅掌柴同时利用部分前期雨水外,其余4种植物均主要利用最近15天内的雨水(利用比例的平均值之和均超过80%)。旱季,5种植物均主要利用最近一次雨水与前期雨水(一个月前)的混合(利用比例的平均值之和均超过80%),其中乔木和常绿灌木对前期雨水的利用比例更高(利用比例的平均值均超过50%)。植被良好的石灰岩连片出露石丛生境中,植物主要以不同时期的雨水为主要水源,这可能与石灰岩发育的裂隙及其储水能力有关。储存在裂隙中的雨水通过植物蒸腾的方式返回大气,这一良好的水文循环过程应得到充分的保护。Aims Woody plants in karst regions often grow on the continuous rock outcrops. However, the source of water for these plants is unclear. This study aimed at investigating the seasonal variation of water sources for plants growing on continuous limestone outcrops in southwestern China. Methods Stable isotope techniques were used to access plant water uptake patterns for five different species in both wet and dry seasons. Then the IsoSource model was used to determine the probable contribution of each po- tential water source to total plant water uptake. Important findings In the wet season, an average of 〉80% of water for four of the five species came from rainwater received in the previous 15 days and stored in fissures in shallow layers. Water accessed by the other species came mostly from recent rainwater; however, the species simultaneously absorbed water from fissures in deep layers that had been recharged from previous precipitation. In the dry season, all five species utilized both recent and previous rainwater, and the two tree species and one large evergreen shrub species used more previous rainwater （〉50%）.

关 键 词：连片出露石丛 IsoSource模型 石灰岩 稳定同位素 植物水分来源 

分 类 号：Q948[生物学—植物学]