出露基岩生境典型植物树干液流对自然降水和连续干旱的响应特征  

Responses of sap flow to natural rainfall and continuous drought of tree species growing on bedrock outcrops

作　　者：张慧玲 丁亚丽[1,2,3] 陈洪松[1,2] 王克林 聂云鹏[1,2] ZHANG Hui-ling;DING Ya-li;CHEN Hong-song;WANG Ke-lin;NIE Yun-peng(Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China;Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China;University of Chinese Academy of Sciences, Beijing 100049, China）.)

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547100 [3]中国科学院大学,北京100049

出　　处：《应用生态学报》2018年第4期1117-1124,共8页Chinese Journal of Applied Ecology

基　　金：国家重点研发计划项目(2016YFC0502402);国家自然科学基金项目(31570428);中国科学院西部青年学者项目(聂云鹏)资助~~

摘　　要：以西南喀斯特地区常见的出露基岩生境为研究对象,针对该类生境典型乔木类植物菜豆树和圆叶乌桕,应用TDP热扩散探针技术,结合遮雨试验,分析了植物树干液流对自然降水和连续干旱的响应特征.结果表明:在生长季不同时期,降水后2树种液流密度较降水前均有一定程度的升高,但始终呈现落叶乔木圆叶乌桕高于半落叶乔木菜豆树的特征;连续2个月遮雨条件下,2树种液流密度均无明显降低的趋势,表明2树种均不依赖受近期降水主导的水源;通过对降水前后及连续干旱条件下2树种液流密度与环境因子的拟合关系研究发现,气象因素差异对水分环境变化条件下植物蒸腾耗水的影响较小.自然降水和短时期的连续干旱并未显著改变2树种的蒸腾耗水特征,这可能与出露基岩生境特殊的水分蓄持环境和乔木类植物依赖相对稳定的深层水源有关.This study focused on bedrock outcrops, a very common habitat in karst region of south- west China. To reveal the responses of plant transpiration to natural rainfall and continuous drought, two tree species typical to this habitat, Radermachera sinica and Triadica rotundifolia, were selected as test materials. A rainout shelter was used to simulate continuous drought. The sap flow dynamics were monitored using the method of Granier＇ s thermal dissipation probe （ TDP ）. Our results showed that sap flow density increased to different degrees after rain in different stages of the growing season. Sap flow density of the deciduous species 7＂. rotundifolia was always higher than that of the semi-deciduous species R. sinica. After two months without rainfall input, both species exhibited no obvious decrease in sap flow density, indicating that rainfall was not the dominant source for their water uptake, at least in the short-tenn. Based on the regression relationships between sap flow density and meteorological factors before and after rainfall, as well as at different stages of continu- ous drought, we found that the dynamics of meteorological factors contributed little to plant transpi- ration. The basic transpiration characteristics of both species were not changed in the circumstance of natural rainfall and short-term continuous drought, which would be closely related to the special water storage environments of bedrock outcrops and the reliance on deep water sources by tree species.

关 键 词：喀斯特 菜豆树 圆叶乌桕 液流密度 蒸腾耗水量 

分 类 号：S715.2[农业科学—林学]