西双版纳绞杀植物斜叶榕的水分利用策略

Water use strategy of Ficus tinctoria in tropical rainforest region of Xishuangbanna,Southwestern China

以斜叶榕为研究对象,通过测定其不同生长阶段木质部与各潜在水源的稳定氢、氧同位素组成,以及土壤水分含量、土壤水势、叶片水势等参数,揭示西双版纳地区不同生长阶段的绞杀榕(斜叶榕)在不同季节的水分利用策略.结果表明:浅层土壤(10～50cm)的水势在干热季与雾凉季变化较大,较深土壤(51～120cm)的水势在各季节无明显变化;雾凉季与干热季的土壤含水量之间无显著差异(P=0.64);植物黎明前叶片水势与中午叶片水势随不同生长阶段而异;根据木质部水与各潜在水源的稳定氧同位素以及植物水势等其他参数判定,浅层土壤水是斜叶榕全年最主要的水分来源,不同生长阶段的斜叶榕在不同季节采取了不同的水分利用策略来应对环境的变化.

Based on the measurement of the stable isotope ratios of hydrogen and oxygen in soil,fog,rain,and plant non-photosynthetic tissues,as well as the gravimetric soil water content,soil water potential,and leaf water potential,this paper studied the water use strategy of F.tinctoria at its different life stages in Xishuangbanna of Southwestern China.The water potential in shallow soil layer（10 -50 cm） had a greater change between hot-dry season and foggy season,whereas that in deeper soil layer（51 -120 cm） had less change during the seasons.No significant difference was observed in the soil water content between foggy season and hot-dry season.The leaf water potential at predawn and midday varied with life stage.From the measurement of the stable isotope ratios and other parameters,it was found that shallow soil water was the main water source for F.tinctoria,and F.tinctoria had different water use strategy at its different life stages.