Quantifying the effect of cumulative water stress on stomatal conductance of Eucalyptus globulus and Eucalyptus nitens: a phenomenological approach
Quantifying the effect of cumulative water stress on stomatal conductance of Eucalyptus globulus and Eucalyptus nitens: a phenomenological approach
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DOI：
10.1071/pp98023
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
D. White;C. Beadle;P. Sands;D. Worledge;J. Honeysett
中科院分区：
文献类型：
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作者：
D. White;C. Beadle;P. Sands;D. Worledge;J. Honeysett
本文将水分胁迫的累积效应引入到蓝桉和黑桉上部冠层叶片气孔导度的唯象模型中。灌溉树木的最大观测气孔导度由描述GSU对光、气温和水汽压亏缺的响应的三个函数来调节。该模型用相同的参数值解释了灌溉树种GSU变化的70%。计算了旱作(GSU，R)和灌溉(GSU，I)树的日总电导率。蓝藻和尼氏沼虾的GSU、R/Gsu、i(f(W))与黎明前水势的线性关系仅能解释f(W)变异的46%和30%。计算了前x天(Sψx)黎明前水势的平均值。当x为8时，蓝藻和尼氏沼虾的x分别为8时和20时，这两个物种的f(W)的变化都是由单一的指数衰减函数解释的。这一结果和需要计算的天数(Sψx)与以前对两种植物的叶水分关系、冠层和边材发育以及气孔行为的研究一致。
This paper incorporates the cumulative effect of water stress, in a phenomenological model of stomatal conductance of upper canopy foliage (gsu) for Eucalyptus globulus and Eucalyptus nitens. Maximum observed stomatal conductance of irrigated trees was moderated by three functions describing the response of gsu to light, air temperature and vapour pressure deficit. This model explained 70% of the variation in gsu of irrigated trees using the same parameter values for both species. Daily total conductance was calculated for rainfed (Gsu,R) and irrigated (Gsu,I) trees. Linear relationships between the ratio of Gsu,R/G su,I (f(W)) and pre-dawn water potential explained only 46 and 30%, respectively, of variation in f(W) for E. globulus and E. nitens. The average value of pre-dawn water potential for the preceding x days (Sψx) was calculated for a range of values of x. When x was 8 for E. globulus and 20 for E. nitens a single exponential decay function accounted for 70% of variation in f(W) for both species. This result and the number of days over which it was necessary to calculate (Sψx) were consistent with previous studies of the leaf water relations, canopy and sapwood development, and stomatal behaviour of the two species.