Department of Biological Sciences, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA.
Department of Plant Sciences, University of California, Davis, 1 Shields Ave, Davis, CA, 95616, USA.
New Phytol. 2023 Sep;239(6):2099-2107. doi: 10.1111/nph.19069. Epub 2023 Jun 29.
A surge of papers have reported low leaf vulnerability to xylem embolism during drought. Here, we focus on the less studied, and more sensitive, outside-xylem leaf hydraulic responses to multiple internal and external conditions. Studies of 34 species have resolved substantial vulnerability to dehydration of the outside-xylem pathways, and studies of leaf hydraulic responses to light also implicate dynamic outside-xylem responses. Detailed experiments suggest these dynamic responses arise at least in part from strong control of radial water movement across the vein bundle sheath. While leaf xylem vulnerability may influence leaf and plant survival during extreme drought, outside-xylem dynamic responses are important for the control and resilience of water transport and leaf water status for gas exchange and growth.
大量文献报道了干旱过程中叶片木质部栓塞脆弱性低。在这里，我们重点研究研究较少但更敏感的外部木质部叶片水力对多种内部和外部条件的响应。对 34 个物种的研究表明，外部木质部途径对脱水具有相当大的易损性，对叶片水力响应光的研究也暗示了动态外部木质部响应。详细的实验表明，这些动态响应至少部分源于对穿过叶脉鞘的径向水分运动的强烈控制。虽然叶片木质部脆弱性可能会影响极端干旱条件下叶片和植物的生存，但外部木质部动态响应对于控制和恢复水运输以及叶片水分状况以进行气体交换和生长是重要的。
