Yan Hui, Liu Xiaoli, Ding Hao, Dai Zhiguang, Niu Xiaoli, Zhao Long
College of Agricultural Equipment Engineering, Henan University of Science and Technology, Luoyang 471000, China.
Science and Technology Development Office, Henan University of Science and Technology, Luoyang 471000, China.
Plants (Basel). 2023 May 23;12(11):2076. doi: 10.3390/plants12112076.
To evaluate the physiological responses of Korshinsk peashrub ( Kom.) to water deficit, photosynthetic gas exchange, chlorophyll fluorescence, and the levels of superoxide anion (O), hydrogen peroxide (HO), malondialdehyde (MDA), antioxidant enzymes, and endogenous hormones in its leaves were investigated under different irrigation strategies during the entire growth period. The results showed that leaf growth-promoting hormones were maintained at a higher level during the stages of leaf expansion and vigorous growth, and zeatin riboside (ZR) and gibberellic acid (GA) gradually decreased with an increase in water deficit. At the leaf-shedding stage, the concentration of abscisic acid (ABA) dramatically increased, and the ratio of ABA to growth-promoting hormones increased to a high level, which indicated that the rate of leaf senescence and shedding was accelerated. At the stages of leaf expansion and vigorous growth, the actual efficiency of photosystem II (PSII) (Φ) was downregulated with an increment in non-photochemical quenching () under moderate water deficit. Excess excitation energy was dissipated, and the maximal efficiency of PSII (/) was maintained. However, with progressive water stress, the photo-protective mechanism was inadequate to avoid photo-damage; / was decreased and photosynthesis was subject to non-stomatal inhibition under severe water deficit. At the leaf-shedding stage, non-stomatal factors became the major factors in limiting photosynthesis under moderate and severe water deficits. In addition, the generation of O and HO in the leaves of was accelerated under moderate and severe water deficits, which caused an enhancement of antioxidant enzyme activities to maintain the oxidation-reduction balance. However, when the protective enzymes were insufficient in eliminating excessive reactive oxygen species (ROS), the activity of catalase (CAT) was reduced at the leaf-shedding stage. Taken all together, has strong drought resistance at the leaf expansion and vigorous growth stages, but weak drought resistance at the leaf-shedding stage.
为评估柠条锦鸡儿（Caragana korshinskii Kom.）对水分亏缺的生理响应，在整个生长期间，研究了不同灌溉策略下其叶片的光合气体交换、叶绿素荧光、超氧阴离子（O₂⁻）、过氧化氢（H₂O₂）、丙二醛（MDA）、抗氧化酶及内源激素水平。结果表明，在叶片扩展和旺盛生长阶段，促进叶片生长的激素维持在较高水平，随着水分亏缺加剧，玉米素核苷（ZR）和赤霉素（GA）逐渐降低。在落叶阶段，脱落酸（ABA）浓度急剧增加，ABA与促进生长激素的比值升至较高水平，这表明叶片衰老和脱落速率加快。在叶片扩展和旺盛生长阶段，适度水分亏缺下，光系统II（PSII）的实际效率（ΦPSII）随非光化学猝灭（NPQ）增加而降低，过剩激发能得以耗散，PSII的最大效率（Fv/Fm）得以维持。然而，随着水分胁迫加剧，光保护机制不足以避免光损伤；在严重水分亏缺下，Fv/Fm降低，光合作用受到非气孔限制。在落叶阶段，在中度和严重水分亏缺下，非气孔因素成为限制光合作用的主要因素。此外，在中度和严重水分亏缺下，柠条锦鸡儿叶片中O₂⁻和H₂O₂的产生加速，这导致抗氧化酶活性增强以维持氧化还原平衡。然而，当保护酶不足以清除过量活性氧（ROS）时，在落叶阶段过氧化氢酶（CAT）活性降低。综上所述，柠条锦鸡儿在叶片扩展和旺盛生长阶段具有较强的抗旱性，但在落叶阶段抗旱性较弱。
