Recovery performance in xylem hydraulic conductivity is correlated with cavitation resistance for temperate deciduous tree species.
Recovery performance in xylem hydraulic conductivity is correlated with cavitation resistance for temperate deciduous tree species.
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DOI：
10.1093/treephys/tpt010
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发表时间：
2013-04
期刊：
影响因子：
4
通讯作者：
Mayumi Y Ogasa;N. Miki;Y. Murakami;K. Yoshikawa
中科院分区：
文献类型：
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作者：
Mayumi Y Ogasa;N. Miki;Y. Murakami;K. Yoshikawa
木质部空化对木质部的水力易损可能会导致木质部栓塞。这些物种如何应对累积栓塞的可能性尚不清楚。在这项研究中，我们研究了7种温带木本植物，以评估低空化阻力（对空化的高脆弱性）通过容器再填充获得高恢复性能的假设。我们还评估了叶片的功能和木质部结构特征。木质部恢复指数（xylem recovery index， XRI）是指土壤干旱后复水植株的木质部导水率与湿润条件下植株的木质部导水率之比。造成50%水力电导率损失的木质部水势（Ψ50）在研究的物种之间存在差异，而在正午木质部水势（Ψmin）方面仅检测到轻微差异，这表明更容易发生空化的物种的水力安全边际（Ψmin - Ψ50）更小。抗空化能力（|Ψ50|）与XRI呈负相关，易空化的树种在木质部恢复方面表现出更高的表现。木材密度与空化阻力呈正相关，与XRI呈负相关。这些新结果表明，木质部的抗空泡性能与木质部恢复性能之间存在协调关系，这与木材的功能性状有关，如抗空泡木质部的木材密度较大，而可再填充木质部的木材密度较小但可储水。这些发现为在可变环境条件下生长的树种的长期水运维持提供了见解。
Woody species hydraulically vulnerable to xylem cavitation may experience daily xylem embolism. How such species cope with the possibility of accumulated embolism is unclear. In this study, we examined seven temperate woody species to assess the hypothesis that low cavitation resistance (high vulnerability to cavitation) is compensated by high recovery performance via vessel refilling. We also evaluated leaf functional and xylem structural traits. The xylem recovery index (XRI), defined as the ratio of xylem hydraulic conductivity in plants rewatered after soil drought to that in plants under moist conditions, varied among species. The xylem water potential causing 50% loss of hydraulic conductivity (Ψ50) varied among the species studied, whereas only a slight difference was detected with respect to midday xylem water potential (Ψmin), indicating smaller hydraulic safety margins (Ψmin - Ψ50) for species more vulnerable to cavitation. Cavitation resistance (|Ψ50|) was negatively correlated with XRI across species, with cavitation-vulnerable species showing a higher performance in xylem recovery. Wood density was positively correlated with cavitation resistance and was negatively correlated with XRI. These novel results reveal that coordination exists between cavitation resistance and xylem recovery performance, in association with wood functional traits such as denser wood for cavitation-resistant xylem and less-dense but water-storable wood for refillable xylem. These findings provide insights into long-term maintenance of water transport in tree species growing under variable environmental conditions.