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根据喀斯特地质特点,建立水分供应分层模拟柱(土壤层-岩石层-岩溶水层),并设置不同土壤水分梯度:重度干旱、中度干旱、水分适宜和水分饱和(相当于土壤田间持水量的30%～40%、50%～60%、70%～80%和90%～100%),研究2年生青冈栎(Cyclobal-anopsis glauca)苗木在模拟喀斯特生境下地经生长量、枝条生长量、光合曲线特征以及光合参数变化。结果表明:土壤干旱胁迫能显著降低青冈栎地径和枝条生长量,但在岩溶层有水的条件下,地径生长量不受土壤干旱胁迫影响;青冈栎的光合作用-光响应曲线符合非直角双曲线函数模型,不同处理光响应曲线的变化趋势基本一致;最大净光合速率和表观量子效率均表现为水分饱和>水分适宜>中度干旱>重度干旱;土壤干旱胁迫使青冈栎光饱和点降低、光补偿点升高,但岩溶水层有水时情况发生改变。
According to the geological characteristics of karst, a layered model column (soil layer - rock layer - karst water layer) for water supply was set up, and different soil moisture gradients were set up: severe drought, moderate drought, water suitable and water saturation (equivalent to soil field water holding capacity The growth of 2-year-old Cyclo-o-Anopsis glauca seedlings in simulated karst habitats was studied by measuring the amount of growth, shoot growth , Photosynthetic curve characteristics and photosynthetic parameters. The results showed that soil drought stress significantly reduced the diameter and branch growth of Quercus acutissima. However, under the condition of water in karst layer, the diameter growth was not affected by soil drought stress. The photosynthesis - The curves of right angle hyperbolic function showed that the trend of photoresponse curve of different treatments was basically the same. The maximum net photosynthetic rate and apparent quantum yield were saturated with water, moderate with water, moderate with severe drought, and light with saturated soil The point is lower and the light compensation point is higher, but the situation changes when there is water in karst water layer.