《植物生理学报》 2017, 53(4): 632-640
通信作者：蔡靖；E-mail: cjcaijing@163.com
摘 要：
以加杨(Populus ×canadensis)扦插苗为研究对象, 进行不同程度的控水处理, 并将其分为对照组、中度胁迫组和重度胁迫组。通过研究不同土壤水分条件造成的木质部结构特征、水力特征、生理特征的变化, 以及与栓塞脆弱性的关系, 探究加杨水力学与生理特性对不同土壤水分条件的响应, 为树木适应干旱环境的生理生态特性提供基础理论依据。结果表明: 三组加杨的枝条水势(P50)大小为对照组>中度胁迫组>重度胁迫组, 加杨通过栓塞脆弱性的变化对不同土壤水分条件表现出一定的响应性; 导管直径、导水率、日平均净光合速率均随着土壤水分含量的降低而减小; 而栓塞程度则随着土壤水分胁迫的增强而增大。回归分析表明导管直径、导水率、日平均净光合速率与P50之间呈正相关(R2分别为0.615、0.677和0.547); 而栓塞程度与P50之间呈负相关(R2=0.597)。因此, 加杨的木质部导管直径、水力特征和生理指标会随土壤水分条件的不同而产生相应变化, 从而影响其栓塞脆弱性, 进而对不同的土壤水分条件表现出一定的响应。关键词：土壤水分条件; 栓塞脆弱性; 导管直径; 净光合速率
收稿：2016-12-16 修定：2017-03-24
资助：国家自然科学基金(31570588和31270646)。
Corresponding author: CAI Jing; E-mail: cjcaijing@163.com
Abstract:
Populus ×canadensis (Canadian poplar) was studied, the poplars can be divided into well-watered plants group, moderately water-stressed plants group and severely water-stressed plants group, and then the different levels of water control treatment were conducted. By studying the characteristics of wood structure, hydraulic characteristics and physiological characteristics under different soil moisture conditions and the relationship with embolism vulnerability, we explored the response of hydraulic and physiological characteristics to different soil moisture conditions in P. ×canadensis to provide basic theoretical basis for the physiological and ecological characteristics of plants to drought environment. The results show that the order of P50 values was well-watered>moderately water-stressed>severely water-stressed; it showed the corresponding response to different soil moisture conditions by the variation of xylem vulnerability. The vessel diameter, hydraulic conductivity and the average of daily net photosynthetic rate were reduced with the reduction of the soil moisture conditions, while the embolism level increased. Regression analysis indicates that vessel diameter, hydraulic conductivity and the average of daily net photosynthetic rate were positively correlated with P50 (R2=0.615, 0.677 and 0.547, respectively). However, the embolism level had a negative correlation with P50 (R2=0.597). Therefore, the xylem structure, hydraulic characteristics and physiological indexes of P. ×canadensis were varied with the different soil moisture conditions, thus affecting the vulnerability, and then showed corresponding response to different soil moisture conditions.Key words: soil moisture condition; embolism vulnerability; vessel diameter; net photosynthetic rate
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