漓江流域喀斯特地区不同果药复合种植模式植物水分利用效率

Plant Water Use Efficiency of Different Intercropping Patterns in the Karst Area of the Lijiang River Watershed

水分是限制喀斯特地区植物生长的关键因子,了解不同果药复合种植模式的种间水分关系至关重要。为探究漓江流域喀斯特地区主要果树和药用植物选择及复合种植模式的合理性,以李树的不同复合种植模式为对象,通过采集叶片并测定其稳定碳同位素值(δ^(13)C),分析植物水分利用效率(WUE)差异,探讨复合种植模式的稳定性及合理性。结果表明:6种植物叶片δ^(13)C和WUE变化范围分别为-31.6‰~-28.7‰和20.56~37.94μmol/mol,δ^(13)C与WUE排序为地枫皮>李树>半枫荷>广西甜茶>金丝桃>黄花倒水莲,可见地枫皮、李树和半枫荷比较适宜种植于喀斯特干旱生境,广西甜茶和金丝桃次之,而黄花倒水莲不适宜栽植于干旱生境。在李树+金丝桃、李树+黄花倒水莲、李树+广西甜茶这3种复合种植模式中,李树的WUE显著高于其林下套种的药用植物,模式内物种间适合度差异显著,复合种植模式稳定性较差;李树+半枫荷+地枫皮模式的WUE最高,且3个树种的WUE差异不显著,适合度相当,物种可以稳定共存,是漓江流域喀斯特地区比较理想的农林复合种植模式。

Water is an essential factor limiting plant growth in Karst regions,so understanding the water relationships among different interspecific plants combinations in various intercropping patterns is important.To explore the plausibility of selecting of major non-woord tree species and medicinal plants,this study measured the stable carbon isotope composition of plant leaves in Prunus salicina-based on intercropping patterns and analyzed plant water use efficiency(WUE)to investigate the stability and plausibility of intercropping patterns.The results showed that theδ^(13)C values and WUE of the six plantsleaves range from-31.6‰to-28.7‰and 20.56 to 37.94μmol/mol,respectively.The rankings ofδ^(13)C and WUE were as follows:Illicium difengpi>P.salicina>Semiliquidambar cathayensis>Rubus chingii>Hypericum monogynum>Polygala fallax.It can be seen that I.difengpi,P.salicina,and S.cathayensis were more suitable for planting in Karst arid habitats,followed by R.chingii and H.monogynum,but P.fallax was not suitable for planting in such conditions.The WUE of P.salicina was significantly higher than that of the medicinal understory plants in the P.salicina+H.monogynum,P.salicina+P.fallax,and P.salicina+R.chingii,which exhibited significant differences in species fitness,indicated lower intercropping patterns stability.The P.salicina+S.cathayensis+I.difengpi had the highest WUE,and no significant differences in WUE were observed among the three tree species.This indicates their comparable fitness and stable coexistence.As a result,this intercropping patterns is considered an ideal model for agroforestry integration in the Karst region of the Lijiang River Watershed.