Zhang Feng-Ping, Zhang Jiao-Lin, Brodribb Timothy J, Hu Hong
CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China.
College of Traditional Chinese Medicine, Yunnan Key Laboratory of Dai and Yi Medicines, Yunnan University of Chinese Medicine, Kunming, 650500, Yunnan, China.
Plant Divers. 2020 Nov 26;43(4):324-330. doi: 10.1016/j.pld.2020.11.007. eCollection 2021 Aug.
Variation in resistance of xylem to embolism among flowers, leaves, and stems strongly influences the survival and reproduction of plants. However, little is known about the vulnerability to xylem embolism under drought stress and their relationships to the anatomical traits of pits among reproductive and vegetative organs. In this study, we investigated the variation in xylem vulnerability to embolism in peduncles, petioles, and stems in a woody plant, . We analyzed the relationships between water potentials that induced 50% embolism (P) in peduncles, petioles, and stems and the conduit pit traits hypothesized to influence cavitation resistance. We found that peduncles were more vulnerable to cavitation than petioles and stems, supporting the hypothesis of hydraulic vulnerability segmentation that leaves and stems are prioritized over flowers during drought stress. Moreover, P was significantly correlated with variation in the dimensions of inter-vessel pit apertures among peduncles, petioles and stems. These findings highlight that measuring xylem vulnerability to embolism in reproductive organs is essential for understanding the effect of drought on plant reproductive success and mortality under drought stress.
花朵、叶片和茎干木质部对栓塞的抗性差异，对植物的存活和繁殖有着强烈影响。然而，对于干旱胁迫下木质部栓塞的脆弱性，以及它们与生殖器官和营养器官中纹孔解剖特征之间的关系，我们却知之甚少。在本研究中，我们调查了一种木本植物的花柄、叶柄和茎干中木质部栓塞脆弱性的变化。我们分析了花柄、叶柄和茎干中诱导50%栓塞（P）的水势与假定影响抗气穴化的导管纹孔特征之间的关系。我们发现，花柄比叶柄和茎干更容易发生气穴化，这支持了水力脆弱性分段假说，即在干旱胁迫期间，叶片和茎干比花朵具有优先地位。此外，P与花柄、叶柄和茎干中导管间纹孔孔径的变化显著相关。这些发现突出表明，测量生殖器官中木质部栓塞的脆弱性，对于理解干旱对植物生殖成功的影响以及干旱胁迫下的死亡率至关重要。
