黄土半干旱区元宝枫叶片气体交换参数对土壤水分的响应  

Responses of Gas Exchange Parameters of Acer truncatum to Soil Water Varivation in a Semi-arid Region of the Loess Plateau

作　　者：巩玉霞[1] 贺康宁[1] 朱艳艳[1] 唐道锋[1] 

机构地区：[1]北京林业大学水土保持学院,北京100083

出　　处：《水土保持研究》2007年第1期242-245,共4页Research of Soil and Water Conservation

基　　金：国家自然科学基金(30371173);教育科学技术研究项目(重大10407)

摘　　要：在黄土高原半干旱地区，采用Li-6400便携式光合测定仪和TDR水分仪，对不同土壤水分处理下的元宝枫（Acer truncatum）盆栽苗木生长的生理生态特征进行观测。研究了叶片的净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）、气孔导度（Gs）、胞间CO2浓度（Ci）和气孔限制值（Ls）对土壤含水量（SWC）的响应过程，并探讨了在不同土壤水分胁迫程度下影响元宝枫叶片光合作用变化的规律，最后确定了元宝枫树种在黄土区适宜生长的土壤水分调控标准。结果表明：元宝枫叶片净光合速率最高时的SWC为14％，蒸腾速率最高时的SWC为15％，叶片水分利用效率最高时的SWC为13％，8％的SWC是严重水分胁迫下叶片光合速率降低由气孔因素限制到非气孔因素限制的转折点。根据半干旱地区林业建设以提高林木水分利用效率为核心的土壤水分管理思想，确定元宝枫树种在该区最适宜生长的SWC为11％～15％。Using a portable Li-6400 photosynthesis system and a TDR moisture meter, the physio-ecology characters of three-year-old spotted Acer truncatums under different soil water contents（SWC） was observed in a semi-arid region of the Loess Plateau. And the responses processes of some parameters to SWC were studied,including net photosynthetic rate, transpiration rate,water use efficiency（WUE）,stomatal conductance, intercellular CO2 concentration and stomatal limiting value, and the effects of soil water stress on the photosynthesis and the fitting range of SWC of Acer truncatum were explored and got. The result showed that the optimum SWC keeping the highest net photosynthetic rate and transpiration rate of Acer truncatum was 14% and 15%,the best SWC to support the highest WUE was 12.8% and 8% of SWC was the turning point of the two factor , which lead to the decrease of net photosynthetic rate from stomatal limitation to non-stomatal limitation under severe water stress. According to the main intention of soil water management for enhancing WUE, it was concluded that the suitable range of SWC of Acer truncatum was within a range of 11% - 15 %.

关 键 词：元宝枫 光合速率 蒸腾速率 水分利用效率 土壤含水量 

分 类 号：S152.7[农业科学—土壤学]