北京林业大学学报2017，Vol.39Issue(9)：8-16,9.DOI:10.13332/j.1000--1522.20160332
胡杨的夜间蒸腾——来自树干液流、叶片气体交换及显微结构的证据
Nocturnal transpiration of Populus euphratica authenticated by measurements of stem sap flux, leaf gas exchange and stomatal microsturcture
摘要
Abstract
Nocturnal transpiration, as a consequence of incomplete stomatal closure, is prevalent across species and environments, and high nocturnal atmospheric vapor pressure deficit ( VPD ) along with high soil water availability are the most commonly reported environmental drivers of it, which is coincided with the conditions of riparian forest in extremely arid region. Based on the measurements of xylem sap flux, leaf gas exchange, stomatal microstructure and environmental factors, we confirmed the occurrence of nocturnal transpiration in P. euphratica from followings:1) incomplete stomatal closure was observed and mean stomatal conductance was 45 mmol/(m2·s), greater than the minimum stomatal conductance of Populus spp. reported in the literature ( approximately 5 mmol/( m2 ·s ) ) , and along with mean transpiration of 0. 7 mmol/( m2·s) , both accounting for 26% and 17% of daytime, respectively. This suggested that high stomatal conductance and transpiration are largely resulted from stomatal opening. 2) On average, sap velocity was 31. 3 cm/hour at daytime and 16. 5 cm/hour at nighttime, which accounting for 53% of daytime. Whether during daytime or nighttime, sap velocity was logarithmic positively related with VPD, and this could explain 55% of nighttime sap velocity change, suggesting that nighttime sap flow was composed of transpiration and tissue refilling. Thus, further research to distinguish the nocturnal transpiration and tissue refilling is needed. Noteworthly, the abruptly increased sap flow after midnight was synchronized with the stem radius change and water potential, but oppositely with VPD, showing that increased sap flow after midnight was induced by tissue refilling but not transpiration.关键词
树干液流/叶片气体交换/气孔显微结构/夜间蒸腾/组织补水Key words
stem sap flux/leaf gas exchange/stomatal microstructure/nocturnal transpiration/tissue refilling分类
农业科技引用本文复制引用
鱼腾飞,冯起,司建华,张小由,赵春彦..胡杨的夜间蒸腾——来自树干液流、叶片气体交换及显微结构的证据[J].北京林业大学学报,2017,39(9):8-16,9.基金项目
国家自然科学基金项目(41401033、31370466、41271037)、中国博士后科学基金(2014M560819). （41401033、31370466、41271037）
