生态学杂志2013，Vol.32Issue(7)：1770-1779,10.
华南荷木林冠层气孔导度对水汽压亏缺的响应
Responses of canopy stomatal conductance of Schima superba stand to vapor pressure deficient in southern China
摘要
Abstract
Canopy stomatal conductance (Gs) is an important parameter quantifying the stomatal performance at canopy level,being able to characterize the exchange dynamics of vapor and energy of forest canopy.In this paper,the sap flow in a Schima superba stand in southern China was continuously monitored with Granier' s thermal dissipation probes,and the canopy transpiration of the stand was obtained through data upscaling methodology.In combining with the microclimatic observations,the Gs was estimated by using Penman-Monteith equation,and the responses of the Gs to vapor pressure deficit under different soil water conditions (wet season vs.dry season) were compared.The estimated Gs based on the sap flow measurement was in the same order of magnitude as that of the leaf stomatal conductance (gs) determined by gaseous exchange method,and similar patterns of the diurnal variations of both Gs and gs were observed.The responses of the Gs to vapor pressure deficit in wet and dry seasons had obvious difference.In wet season (soil water content θ＞ 33％),the Gs was more sensitive to vapor pressure deficit (partial coefficient -0.316) ; in dry season (θ＜ 23％),the Gs was more sensitive to photosynthetically active radiation (PAR) (partial coefficient 0.885).The decoupling coefficient (Ω) of stand canopyatmosphere was close to 1 (maximum value) in wet season but substantially smaller in dry season,indicating that vapor pressure deficit had little effects on Gs in wet season probably due to the thicker boundary layers on leaves,while PAR was the main environmental factor controlling Gs.关键词
荷木/树干液流/冠层气孔导度/脱耦联系数Key words
Schima superba/ sap flow/ canopy stomatal conductance/ decoupling coefficient分类
农业科技引用本文复制引用
曹庆平,赵平,倪广艳,朱丽薇,牛俊峰,曾小平..华南荷木林冠层气孔导度对水汽压亏缺的响应[J].生态学杂志,2013,32(7):1770-1779,10.基金项目
国家自然科学基金项目(41030638,31170673,41275169)和广东省自然科学基金项目(S2012020010933)资助. （41030638,31170673,41275169）
