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以西南喀斯特地区常见的出露基岩生境为研究对象,应用TDP热扩散探针技术,分析2种典型乔木菜豆树和圆叶乌桕的树干液流特征.结果表明:2树种树干液流对干、湿季均有明显响应;同为落叶乔木,菜豆树(约1个月)无液流特征的时长远小于圆叶乌桕(约4个月);圆叶乌桕单位胸高断面积年总蒸腾耗水量高于菜豆树,生长季内(4—9月)2树种单位胸高断面积耗水量分别约占全年的90%和66%;2树种液流密度与光合有效辐射、水汽压亏缺、温度均呈极显著正相关,与相对湿度呈极显著负相关;2树种生长季内液流密度、日蒸腾耗水不仅小于同处于亚热带季风区的非喀斯特地区,而且小于邻近的喀斯特地区,甚至低于降水稀少的干旱地区典型树种同一参数的值.喀斯特出露基岩生境2种典型植物的蒸腾耗水量因特殊的水分环境而受到限制,同为落叶乔木却对应着不同的水分利用策略.
Based on the common exposed bedrock habitat in the southwest karst area, TDP thermal diffusion probe technique was used to analyze the characteristics of the sap flow in two typical tree species, , Wet season have significant response; the same deciduous trees, beans (about 1 month) no flow characteristics of the duration is much smaller than the melanogaster (about 4 months); The amount of water in the thoracic and cross-sectional area of the two tree species units accounted for about 90% and 66% of the annual total in the growing season (April-September) respectively. The flow density and the photosynthetic active radiation, water vapor pressure deficit, There was a significant and significant negative correlation between temperature and relative humidity. The flow density and daily transpiration water consumption during the growing season were not only less than those in the non-karst areas in the subtropical monsoon region but also smaller than those in the neighboring karst regions Which is lower than the same parameter of the typical tree species in arid areas with low precipitation.The transpiration water consumption of two typical plants in the karst exposed bedrock habitat is limited by the special water environment and deciduous trees correspond to different water use strategies.