| 木本植物水力系统对干旱胁迫的响应机制 |
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| 引用本文： | 罗丹丹,王传宽,金鹰. 木本植物水力系统对干旱胁迫的响应机制[J]. 植物生态学报, 2021, 45(9): 925-941. DOI: 10.17521/cjpe.2021.0111 |
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| 作者姓名： | 罗丹丹 王传宽 金鹰 |
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| 作者单位： | 东北林业大学生态研究中心, 哈尔滨 150040 |
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| 基金项目： | 中央高校基本科研业务费专项资金项目(2572018AA07);国家重点研发计划(2016YFD0600201);教育部长江学者和创新团队发展计划(IRT_15R09) |
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| 摘 要： | 干旱导致树木死亡对生态系统功能和碳平衡有重大影响。植物水分运输系统失调是引发树木死亡的主要机制。然而, 树木对干旱胁迫响应的多维性和复杂性, 使人们对植物水分运输系统在极端干旱条件下的响应以及植物死亡机理的认识还不清楚。该文首先评述衡量植物抗旱性的指标, 着重介绍可以综合评价植物干旱抗性特征的新参数——气孔安全阈值(SSM)。SSM越高, 表明气孔和水力性状之间的协调性越强, 木质部栓塞的可能性越低, 水力策略越保守。然后, 阐述木本植物应对干旱胁迫的一般响应过程。之后, 分别综述植物不同器官(叶、茎和根)对干旱胁迫的响应机制。植物达到死亡临界阈值的概率和时间, 取决于相关生理和形态学特征的相互作用。最后, 介绍木本植物水力恢复机制, 并提出3个亟待开展的研究问题: (1)改进叶片水分运输(木质部和木质部外水力导度)的测量方法, 量化4种不同途径的叶肉水分运输的相对贡献; (2)量化叶片表皮通透性变化, 以便更好地理解植物水分利用策略; (3)深入研究树木水碳耦合机制, 将个体结构和生理特征与群落/景观格局和过程相关联, 以便更好地评估和监测干旱诱导树木死亡的风险。
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| 关 键 词： | 抗旱性 木质部栓塞 气孔调节 树木死亡 水力性状 |
| 收稿时间： | 2021-03-25 |
Response mechanisms of hydraulic systems of woody plants to drought stress |
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| LUO Dan-Dan,WANG Chuan-Kuan,JIN Ying. Response mechanisms of hydraulic systems of woody plants to drought stress[J]. Acta Phytoecologica Sinica, 2021, 45(9): 925-941. DOI: 10.17521/cjpe.2021.0111 |
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| Authors: | LUO Dan-Dan WANG Chuan-Kuan JIN Ying |
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| Affiliation: | Center for Ecological Research, Northeast Forestry University, Harbin 150040, China |
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| Abstract: | Drought-related tree mortality profoundly impacts the ecosystem functions and carbon budgets, in which one of the principal mechanisms involved is the catastrophic failure of the hydraulic systems. However, our understanding of tree hydraulic systems and the mechanisms of tree death under extreme drought conditions are limited because the responses of trees to drought stress are multi-dimensional and complex. In this review, we first expounded the indexes of measuring plant drought resistance, and focused on the stomatal safety margin (SSM) that can be used to comprehensively evaluate the drought tolerance of plants. A larger positive value of SSM indicates a stronger coordination between stomata and hydraulic traits, a lower possibility of xylem embolization, and a more conservative hydraulic strategy adopted. Second, we integrated general response processes of woody plants to drought stress. Third, we introduced response mechanisms of different plant organs (leaf, stem and root) to drought stress. The probability of reaching the critical threshold and the duration of tree death are determined by interactions between physiological and morphological traits. Finally, we discussed hydraulic recovery mechanisms of woody plants, and put forward three research priorities in the future: (1) to improve the methodology for measuring leaf hydraulic conductance, especially the xylem and outside-xylem hydraulic conductance, and quantify the relative contributions of the four water transport pathways in mesophyll tissues; (2) to quantify variations in the epidermal permeability for better understanding plant water-use strategies; and (3) to deepen the understanding of the water-carbon coupling mechanisms, and link individual-level structural and physiological traits with patterns and processes at the community and landscape levels, so as to better assessing and monitoring the potential risk of drought-induced tree mortality. |
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| Keywords: | drought resistance xylem embolism stomatal adjustment tree mortality hydraulic trait |
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