火炬树克隆片段在异质水分斑块中的水分 及光响应初步研究

为探索木本克隆植物火炬树Rhus typhina母株与子株是否存在水分生理整合的生理生态过程，以火炬树母株与子株组成的克隆片段为研究对象，在母株后和子株前10 cm处截断水平根系并对子株进行浇水处理，以不浇水的克隆片断为对照，采用PSYPRO多露点水势仪和Li-6400xT光合分析仪，测定分析了火炬树克隆片段内母株与子株叶片的水势及光合参数。结果表明:①对子株浇水500 mL后，处理母株与处理子株的水势均升高，处理母株的升幅为48.7%，处理子株的升幅为82.1%，差异不显著（P＞0.05），说明火炬树克隆子株片段在保证自身水分需要的同时，通过间隔子向母株传输水分，证实火炬树母株与子株间存在水分共享的传输机制。②处理母株的净光合速率Pn，蒸腾速率Tr，气孔导度Gs及胞间二氧化碳摩尔分数Ci的响应值均超过了处理子株； 处理子株与对照子株的净光合速率Pn，蒸腾速率Tr，气孔导度Gs，及胞间二氧化碳质量分数Ci比较均无明显升高或下降。母株与子株的差异不显著（P＞0.05）。③通过光响应曲线拟合，火炬树母株的光补偿点较低，光饱和点较高，表观量子效率较大。通过水分控制处理形成异质水分生境后，火炬树子株的光饱和点升高，光补偿点与表观量子效率均降低。图3表2参40

Water and light response on cloned fragments of Rhus typhina with different water heterogeneous patches

Physiological integration characteristics of woody clonal plants has important influence on their use of habitat resources and colonization.To explore the water sharing mechanism in genets and ramets of Rhus typhina，fragments of genets and ramets were selected as the experimental material. Then，the water and light response on cloned fragment of Rhus typhina was studied comparing the genets and ramets in different water heterogeneous patches by measuring water potential and photosynthesis with PSYPRO Water Potential System and Li-6400xT Photosynthesis Analyzer. Results showed that:（1） after adding 500 mL water to the ramets，the water potential of the genets increased 48.7% and the ramets increased 82.1%；however，there were no significant differences（P＞0.05）. （2） It is more sensitive than that of the ramets that the response of the net photosynthetic rate，transpiration rate，stomatal conductance，and intercellular CO2 concentration of the genets to the water，but it was not significant that the difference of increase between genets and ramets（P＞ 0.05）. （3） The fitting of light response curve indicated light compensation point of the genets is lower；light saturation point，higher；apparent quantum efficiency，higher；Thus，for clonal ramets，water sharing mechanisms exist for the genets and ramets of R. typhina in water heterogeneous habitat.［Ch，3 fig. 2 tab. 40 ref.］