College of Life and Environmental Sciences, Hangzhou Normal University, Yuhangtang Road 2318, Hangzhou 311121, China.
Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 27, Latokartanonkaari 5, Helsinki FI-00014, Finland.
Tree Physiol. 2022 Jul 5;42(7):1350-1363. doi: 10.1093/treephys/tpac011.
The increased frequency and intensity of drought pose great threats to the survival of trees, especially in dioecious tree species with sexual differences in mortality and biased sex ratios. The sex-specific mechanisms underlying stem xylem anatomy and function and carbon metabolism in drought resistance and recovery were investigated in dioecious Populus cathayana Rehder. The sex-specific drought resistance and subsequent recovery were linked to the xylem anatomy and carbon metabolism. Females had a greater xylem vessel area per vessel, biomass and theoretically hydraulic efficiency under well-watered conditions. Conversely, males had a lower xylem lumen area, but greater vessel numbers, and a higher cell wall thickness, suggesting a theoretically conservative water-use strategy and drought resistance. The recovery of photosynthetic ability after drought in males was largely dependent on the recovery of xylem function and the regulation of the xylem carbohydrate metabolism. Additionally, the number of upregulated genes related to xylem cell wall biogenesis was greater in males relative to females under drought stress and subsequent rewatering, which facilitated drought resistance and xylem function restoration in males. These results suggested that sex-specific drought resistance and restoration were related to xylem anatomy and function, carbohydrate metabolism and cell turgor maintenance.
干旱的频率和强度增加对树木的生存构成了巨大威胁，特别是在雌雄异株树种中，死亡率和性别比例存在差异。本研究以雌雄异株的枫杨为研究对象，探讨了木质部解剖结构和功能以及碳代谢在雌雄异株植物抗旱性和恢复中的性别特异性机制。雌雄异株植物的抗旱性和随后的恢复与木质部解剖结构和碳代谢有关。在水分充足的条件下，雌性的木质部导管面积、生物量和理论水力效率都较大。相反，雄性的木质部管腔面积较小，但导管数量较多，细胞壁较厚，这表明雄性具有理论上保守的用水策略和抗旱性。雄性光合作用能力在干旱后的恢复在很大程度上依赖于木质部功能的恢复和木质部碳水化合物代谢的调节。此外，在干旱胁迫和随后的复水条件下，雄性中与木质部细胞壁生物发生相关的上调基因数量多于雌性，这有助于雄性的抗旱性和木质部功能恢复。这些结果表明，性别特异性的抗旱性和恢复性与木质部解剖结构和功能、碳水化合物代谢以及细胞膨压维持有关。
