果树冠层水分利用效率分布模型构建

The Model of Efficiency on Using Water in Canopy of Fruit Tree

中文关键词: 苹果  水分利用效率  冠层  模拟  小气候  光合作用  蒸腾作用

英文关键词: Apple  Water Use Efficiency  Canopy  Simulation  Microclimate  Photosynthesis  Transpiration

中文摘要:

      为模拟树冠内叶片瞬时水分利用效率(WUEI)的三维分布，构建了三维树冠净光合速率(Pn)和蒸腾速率(Tr)的耦合模型。该模型利用C3植物叶片光合生化模型和Penman-Monteith公式计算Pn和Tr，而WUEI是根据Pn和Tr比值求出。以22年生开心形“富士”苹果树(Malus domestica Borkh. cv. ‘Fuji’)为试材，通过实测确定三维树冠内叶片和辐射分布，并据2007–2008年测定数据拟合相关模型参数。模拟结果表明，从苹果树冠顶部到底部WUEI从3.96 mmol·mol-1降到2.61 mmol·mol-1，只下降了34%，树冠两侧和内膛的差异不到5%。在一天当中苹果冠层WUEI整体呈双峰曲线，晴天的WUEI比阴天高28%，约为2.82 mmol·mol-1。研究表明，该模型可模拟出苹果冠层WUEI的三维分布和日变化。

英文摘要:

      A coupling model of photosynthetic rate (Pn) and transpiration rate (Tr) wasdeveloped to simulate the three-dimensional distribution of leaf instantaneous efficiencyof using water (WUEI) in apple canopy. The leaves Pn and Tr were calculated by the C3photosynthesis model and Penman-Monteith equation. For convenience, WUEI is expressedas the ratio of net Pn to Tr. The experiment was conducted in a‘ Fuji’ apple (Malusdomestica Borkh. cv.‘ Fuji’) orchard during the 2007~2008 growing seasons. Whencanopy height decreased from upper to bottom canopy, WUEI decreased by 34% from 3.96mmol·mol-1 to 2.61 mmol·mol-1 with no more than 5% difference between the sides and theinner part. The diurnal course of WUEI in the canopy showed a double-peak curve on clearday. The average WUEI on clear days was 2.82 mmol·mol-1 which was about 28% higherthan cloudy days. The study indicated that the sensitivity of WUEI to microclimatic factorsand Ψ1 can be systemically assessed by the coupling model