滇东南岩溶山地不同恢复模式云南松水分利用策略的差异

Differences of Water Use Strategies of Pinus yunnanensis in Different Recovery Modes in Karst Mountains in Southeast Yunnan

研究云南松不同恢复模式下的水分利用策略以探究植物合理的种间配置结构,为岩溶区脆弱生态环境的恢复提供重要的科学依据。通过测定云南松及混交群落内4种植物(清香木、香樟、滇青冈、锥连栎)的茎秆水和不同水源的氢氧同位素值,结合植物叶片碳同位素值,进而探究植物的水分利用策略。结果表明:1)岩溶地下水是喀斯特植物的稳定水源,云南松混交林中20~60 cm土壤层含水量显著高于纯林,旱雨季最大相差10.36%和15.19%,表明混交林内水分条件更好。2)云南松混交林相较于纯林,水源的利用比例季节波动小,旱季香樟与清香木加大了对岩溶地下水的利用比例18.1%、19.2%,降低了种间竞争,其深根提升上来的水分又可惠及云南松及浅根植物。3)与纯林中云南松相比,混交林中云南松叶片δ13C值季节变化小,表明水分利用效率相对稳定。云南松可以与清香木、香樟等阔叶树种混交种植,能够提高云南松的存活率,也减少植物群落在水源利用中的竞争。

To study the water utilization strategy of Pinus yunnanensis under different recovery modes,so as to explore the reasonable inter-species configuration of plants,and to provide important scientific basis for the restoration of fragile ecological environment in karst areas.Through measuring the hydrogen and oxygen isotope values of stem water and different water sources of four plants mixed in P.yunnanensis,i.e.,Pistacia weinmannifolia,Cinnamomum camphora,Cyclobalanopsis glaucoides,and Quercus franchetii,and combining the carbon isotope values of plant leaves,the water utilization strategies of plants were explored.1)Karst groundwater was a stable water source for karst plants.The water content in 20-60 cm soil in P.yunnanensis mixed forest was significantly higher than that in pure forest,and the maximum differences in drought and rainy seasons were 10.36%and 15.19%,respectively,indicating that the water condition in mixed forest was better.2)Compared with pure forest,mixed forest of P.yunnanensis had less seasonal fluctuation in water utilization ratio.In dry season,C.camphora and P.weinmannifolia increased the utilization ratio of karst groundwater by 18.1%and 19.2%,resulting the decrease of inter-species competition,and the water raised by deep roots could benefit P.yunnanensis and shallow-rooted plants.3)Compared with P.yunnanensis pure forest,the leafδ13C value of mixed forest had a small seasonal variation,indicating that its water use efficiency was relatively stable.Pinus yunnanensis can be mixed with broad-leaved tree species such as P.weinmannifolia and C.camphora,which can improve the survival rate of P.yunnanensis and reduce the competition of plant communities in water utilization.