Biophysical limits to responses of water flux to vapor pressure deficit in seven tree species with contrasting land use regimes
Biophysical limits to responses of water flux to vapor pressure deficit in seven tree species with contrasting land use regimes
复制标题
七种树种水通量对蒸气压不足响应的生物物理限制与对比土地利用制度
DOI：
10.1016/j.agrformet.2014.10.007
复制
发表时间：
2015-01-15
影响因子：
6.2
通讯作者：
Ni, Guangyan
中科院分区：
文献类型：
--
作者：
Gao, Jianguo;Zhao, Ping;Ni, Guangyan
量化树木对环境变量的敏感性，如蒸汽压赤字（D）是重要的了解水文响应土地利用变化和潜在的生理机制的作用。在2012年和2013年的干旱季节初期，测定了中国南亚热带3个样地幼龄材（5年生）、次生林（25年生）和成熟林（50年生）的树干液流（J（s））、水分输送和冠层气孔导度（G（S））对D（in）的敏感性。J（s）被发现是负相关的树木的生物特征参数，和整个树的水分运输为一个给定的树的大小与年龄或大小，这是部分归因于较低的边材量为一个给定的直径。从幼龄材到成熟材，7个树种的1 kPa下的G（s）（G（sref））和参照G（s）均呈下降趋势，但差异不显著。气孔关闭时的外推值（e（B/m））D在种间差异显著，从等水巨尾桉到不等水大叶相思和柠条桉，D值逐渐减小。J（s）和最大液流（J（s，max））与木材密度下降，表明水分通量的生物物理约束。木材密度是一个很好的预测G（sref）（r（2）= 0.664，P = 0.026），表明水通量D是一个内在的适应特性。据我们所知，这是第一个将木材密度和G（sref）联系起来的研究。水通量对D的响应因物种、大小或年龄以及水力结构而异，这突出表明，基于一种土地利用情景的相同水力参数建模水收支到土地覆盖过渡可能会导致模型预测中的广泛误差。研究结果可用于评价土地利用变化对森林生态系统水文过程的影响。(C)2014爱思唯尔有限公司版权所有。
Quantifying the sensitivity of trees to environmental variables such as vapor pressure deficit (D) is important for understanding the hydrological responses to land use changes and the role of underlying physiological mechanisms. Sap flux (J(s)), water transport, and sensitivity of canopy stomatal conductance (G(S)) to D (in) were determined during the early dry season in 2012 and 2013 for young timber trees (5 years), secondary forest trees (similar to 25 years), and mature forest trees (similar to 50 years) at three sites of lower subtropical China. The J(s) was found to be negatively correlated with tree biometric parameters, and whole tree water transport for a given tree size decreased with age or size, which was partially attributed to the lower sapwood quantity for a given diameter. The in and reference G(s) at 1 kPa (G(sref)) of the seven tree species decreased from young timber to mature trees, although not significantly. The D, which is the extrapolated value when stomata closure (e(b/m)), significantly varied among species, which decreased from isohydric Eucalyptus grandis x urophylla to more anisohydric Acacia auriculiformis and Eucalyptus citriodora. J(s) and maximum sap flux (J(s,max)) decreased with wood density, suggesting that water flux was regulated by biophysical constraints. Wood density was a good predictor of G(sref) (r(2) = 0.664, P = 0.026), indicating that water flux to D is an intrinsic adaptive characteristic. To the best of our knowledge, this is the first study linking wood density and G(sref). The responses of water flux to D varied among species, size or age, and hydraulic architecture, which highlights that modeling water budget to land cover transition based on the same hydraulic parameter from one land use scenario can potentially cause extensive errors in model prediction. Our empirical research could be used for the evaluation of the consequences of land use changes on the hydrological process of forest ecosystems. (C) 2014 Elsevier B.V. All rights reserved.