State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
Plant Physiol Biochem. 2018 Dec;133:116-126. doi: 10.1016/j.plaphy.2018.10.037. Epub 2018 Nov 1.
Myo-inositol mediates various physiological processes and stress responses. Here, we investigated its role in Malus hupehensis Rehd. plants when grown hydroponically under saline conditions. Salt-stressed plants showed reduced growth and marked declines in photosynthetic activity and chlorophyll concentrations. However, pretreatment with 50 μM myo-inositol significantly alleviated those inhibitions and enabled plants to maintain their photosynthetic capacity. In addition to changing stomatal behavior, exogenous myo-inositol inhibited ROS accumulation and Na uptake. In contrast, activities of antioxidant systems were enhanced, and expression was elevated for genes involved in Na uptake (e.g., HKT1, NHX1, SOS1, and SOS2). This exogenous application also provoked the accumulation of sugars or sugar alcohols, which partially contributed to the maintenance of osmotic balance, and the scavenging of ROS, either directly or indirectly. In summary, myo-inositol appears to alleviate the salt-induced inhibition of physiological processes for M. hupehensis, not only by supporting the plant's antioxidant defense system but also by mediating Na and K homeostasis and the osmotic balance.
肌醇参与多种生理过程和应激反应。在这里，我们研究了它在水培盐胁迫条件下生长的平邑甜茶植株中的作用。盐胁迫下的植物生长受到抑制，光合作用活性和叶绿素浓度明显下降。然而，用 50μM 肌醇预处理可显著缓解这些抑制作用，使植物维持其光合作用能力。除了改变气孔行为外，外源肌醇还抑制 ROS 积累和 Na 摄取。相比之下，抗氧化系统的活性增强，同时参与 Na 摄取的基因（如 HKT1、NHX1、SOS1 和 SOS2）的表达水平也升高。这种外源添加还引发了糖或糖醇的积累，这部分有助于维持渗透平衡，并直接或间接地清除 ROS。总之，肌醇似乎通过支持植物的抗氧化防御系统，以及调节 Na 和 K 稳态和渗透平衡，缓解盐胁迫对平邑甜茶生理过程的抑制作用。
