Stomatal and hydraulic conductance and water use in a eucalypt plantation in Guangxi, southern China
Stomatal and hydraulic conductance and water use in a eucalypt plantation in Guangxi, southern China
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DOI：
10.1016/j.agrformet.2014.12.003
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发表时间：
2015-03
影响因子：
6.2
通讯作者：
Liwei Zhu;P. Zhao;Q. Wang;G. Ni;J. Niu;Xiaosong Zhao;Zhenzhen Zhang;P. Zhao;Jianguo Gao
中科院分区：
文献类型：
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作者：
Liwei Zhu;P. Zhao;Q. Wang;G. Ni;J. Niu;Xiaosong Zhao;Zhenzhen Zhang;P. Zhao;Jianguo Gao
先前的研究表明，单位叶面积的恒定水分利用是由气孔导度和水力导度对植物水分利用的联合控制引起的；然而，很少有研究探索中国南方一种普遍种植的速生树种桉树的用水情况。本研究在2012年7月和10月以及2013年1月和4月，利用树液通量、叶水势（ψleaf）和相关环境变量，监测了广西一处5年生桉树grandis×Eucalyptus尾叶林的水力性状和生态生理参数的季节变化。结果表明，各月份的黎明前叶相似，表明研究地点土壤水分丰富。午间叶有显著的季节变化。7月冠层气孔导度（Gs）高于10月，且随水汽压差（ln(VPD)）的自然对数线性降低。此外，干季（10月）单位边材面积土壤对叶片的水力导度(K)相对于湿季（7月）较高。7月和10月全树日需水量分别为7.7 kg d - 1和6.7 kg d - 1，随叶面积的增加呈线性增加。然而，7月和10月全树日用水量与叶面积之间的回复线斜率相似，清楚地表明该桉树单位叶面积的用水量是恒定的，这证实了普遍接受的概念。这项研究的结果应该有助于解决与桉树快速扩张有关的日益严重的生态水文和水资源问题。中国南方的种植园最近经历了严重的干旱。
Previous work has demonstrated that constant water use per unit leaf area results from the combined control of stomatal and hydraulic conductance holds for plant water use; however, few studies have ever explored the water use of a popularly planted fast-grown tree species,eucalyptus, in southern China. In this study, seasonal variations in hydraulic traits and ecophysiological parameters were monitored via the sap flux, leaf water potential (ψleaf) and associated environmental variables to investigate the water use of a five-year-oldEucalyptus grandis×Eucalyptus urophyllaplantation in Guangxi province, China, in July and October 2012 and January and April 2013. The results show that predawnψleafwas similar among all months, suggesting an abundance of soil water in the study site. There was a significant seasonal variation in middayψleaf. Moreover, canopy stomatal conductance (Gs) was higher in July than in October and linearly decreased with the natural logarithm of the vapor pressure deficit (ln(VPD)). Furthermore, the hydraulic conductance from soil to leaves (K) per unit sapwood area in the dry season (October) was relatively high compared to that in the wet season (July). Whole-tree water use per day was estimated to be 7.7 kg d−1and 6.7 kg d−1in July and October, respectively, and linearly increased with leaf area. However, the slope of the regression line between whole-tree water use per day and leaf area was similar in July and October, clearly indicating that thiseucalyptusstand had a constant water use per unit leaf area, which confirms the generally accepted concept. The findings of this study should help address the increasing ecohydrological and water resource concerns related to the rapid expansion ofEucalyptusspp. plantations in southern China, which recently underwent a severe drought.