喀斯特区顶坛花椒适生的土壤水分环境

2005年5月以盆栽顶坛花椒幼苗为对象,在不同水分梯度及充分供水条件下用CI-301 CO2气体分析仪进行林木生理指标观测,研究了顶坛花椒1年生苗净光合速率、蒸腾速率、气孔导度、叶片水分利用效益与土壤含水量的关系,结果表明:维持顶坛花椒净光合作用的最佳土壤含水量为22%,维持顶坛花椒较高蒸腾速率的土壤含水量范围为22.5%～25.6%,气孔导度最大时对应的土壤含水量为25.6%,维持顶坛花椒叶片水分利用效益的最佳土壤含水量为28%,根据喀斯特造林的基本构思,可选取维持最佳叶片水分利用效益的土壤含水量临界值和维持最佳净光合速率的土壤含水量低限值作为喀斯特造林树种顶坛花椒的适宜土壤水分的高限值和低限值。这一指标可量化为22%～28%。

Adaptive soil moisture environment of Zanthoxylum bungeanum growing in Karst Area

In May 2005,physiological index of potted Zanthoxylum bungeanum under different soil moisture condition was measured by CO2 analysis system (CI-301).The correlation among net photosynthetic rate and transpiration rate and stomatic conductivity and leaf water utility efficient with soil moisture content of one-year-old Zanthoxylum bungeanum was studied.The result showed the optimum soil moisture content keeping max net photosynthetic rate of Zanthoxylum bungeanum was 22%.The optimum soil moisture content keeping better transpiration rate of Zanthoxylum bungeanum was between 22.5% and 25.6%.The suitable soil moisture content for max stomatic conductivity was 25.6%.The optimum soil moisture content keeping better leaf water utility efficient was 28%.According to the thought of karst afforestation,the soil moisture content maintaining the best leaf water utility efficient and the better net photosynthetic rate can be regarded as the highest and lowest value.The indexes can be shown as quantity as 22%～28%.