Interaction of stomatal behaviour and vulnerability to xylem cavitation determines the drought response of three temperate tree species
Interaction of stomatal behaviour and vulnerability to xylem cavitation determines the drought response of three temperate tree species
复制标题
气孔行为和木质部空化脆弱性的相互作用决定了三种温带树种的干旱反应
DOI：
10.1093/aobpla/plz058
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发表时间：
2019-10-01
期刊：
影响因子：
2.9
通讯作者：
Wan, Xianchong
中科院分区：
文献类型：
--
作者：
Chen, Zhicheng;Liu, Shirong;Wan, Xianchong
树木的死亡率和生长是如何随着等各向异性连续体和木质部脆弱性的变化而变化的，这仍然是一个争论的问题。在中国半湿润的宝天满山区，对森林进行了轻度干旱条件下的降水减少试验。研究了该地区3种主要的亚冠树种。降雨减少后，黑桫椤出现了严重的枯死现象，而其他两种共生物种没有出现枯死现象。三种植物气孔关闭时的水势分别为- 1.70、- 2.54和- 3.41 MPa，而水导率损失88%时的水势分别为- 2.31、- 2.11和- 7.01 MPa。综上所述，木质部脆弱的近各向异性扁豆对干旱枯死非常敏感。各向异性叶片的最小负水势最大，木质部抗空化能力最强。等水植物日本菊通过快速关闭气孔来保存水分。结果表明，水力学安全边际（HSM）最小，特别是在降水减少的样地。在气孔安全裕度（SSM）方面，烟叶为负，金银花和粳稻为正。在没有枯死病的两种植物中，降雨减少对粳稻的生长有抑制作用，但对白花的生长没有影响；降水减少导致粳稻非结构碳水化合物（NSCs）含量减少，而锦葵非结构碳水化合物含量增加。结果表明，HSM和SSM可以解释三种亚冠物种对干旱的敏感性。干旱诱导的枯死是由气孔行为和木质部脆弱性共同决定的，尽管该物种仍处于半湿润地区，但对气候变化引起的干旱可能很敏感。等水/各向水程度与植物的NSCs状态和生长有关。
Abstract How the mortality and growth of tree species vary with the iso-anisohydric continuum and xylem vulnerability is still being debated. We conducted a precipitation reduction experiment to create a mild drought condition in a forest in the Baotianman Mountains, China, a sub-humid region. Three main sub-canopy tree species in this region were examined. After rainfall reduction, Lindera obtusiloba showed severe dieback, but two other co-occurring species did not show dieback. The water potential at stomatal closure of Dendrobenthamia japonica, L. obtusiloba and Sorbus alnifolia was −1.70, −2.54 and −3.41 MPa, respectively, whereas the water potential at 88 % loss in hydraulic conductivity of the three species was −2.31, −2.11 and −7.01 MPa, respectively. Taken together, near-anisohydric L. obtusiloba with vulnerable xylem was highly susceptible to drought dieback. Anisohydric S. alnifolia had the most negative minimum water potential, and its xylem was the most resistant to cavitation. Isohydric D. japonica conserved water by rapidly closing its stomata. Ultimately, the hydraulic safety margin (HSM) of L. obtusiloba was the smallest among the three species, especially in precipitation-reduced plots. In terms of the stomatal safety margin (SSM), L. obtusiloba was negative, while S. alnifolia and D. japonica were positive. Of the two species without dieback, rainfall reduction decreased growth of D. japonica, but did not influence growth of S. Alnifolia; meanwhile, rainfall reduction led to a decrease of non-structural carbohydrates (NSCs) in D. japonica, but an increase in S. alnifolia. It is concluded that HSM as well as SSM allow interpreting the sensitivity of the three sub-canopy species to drought. The drought-induced dieback of L. obtusiloba is determined by the interaction of stomatal behaviour and xylem vulnerability, and the species could be sensitive to climate change-caused drought although still in sub-humid areas. The isohydric/anisohydric degree is associated with NSCs status and growth of plants.