Chen Lidan, Li Minqing, Li Congjuan, Zheng Weihua, Liu Ran
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Plants (Basel). 2023 Oct 25;12(21):3683. doi: 10.3390/plants12213683.
Drought is an important environmental factor that influences physiological processes in plants; however, few studies have examined the physiological mechanisms underlying plants' responses to continuous drought. In this study, the seedlings and younger individuals of were experimentally planted in the southern part of the Gurbantunggut Desert. We measured their photosynthetic traits, functional traits and non-structural carbohydrate contents (NSCs) in order to assess the effects of continuous drought (at 15-day and 30-day drought points) on the plants' physiological responses. The results showed that at the 15-day (15 d) drought point, the leaf light-saturated net photosynthetic rate (A) values of both the seedlings and the younger individuals were decreased (by -68.9% and -45.2%, respectively). The intrinsic water use efficiency (iWUE) of the seedlings was significantly lower than that of the control group (-52.2%), but there was no diffenrence of iWUE observed in younger individuals. At the 30-day (30 d) drought point, a decrease in the A (-129.8%) of the seedlings was induced via biochemical inhibition, with a lower potential maximum photochemical rate (Fv/Fm, 0.42) compared with the control group, while a decrease in the A (-52.3%) of the younger individuals was induced due to lower stomatal conductance (g, -50.5%). Our results indicated that prolonged drought induced a greater risk of seedling mortality as the relatively limited ability of stomatal regulation may increase the possibility of massive embolism, resulting in hydraulic failure.
干旱是影响植物生理过程的重要环境因素；然而，很少有研究探讨植物对持续干旱响应的生理机制。在本研究中，将[植物名称]的幼苗和幼龄个体实验性地种植在古尔班通古特沙漠南部。我们测量了它们的光合特性、功能特性和非结构性碳水化合物含量（NSCs），以评估持续干旱（在干旱15天和30天时间点）对植物生理响应的影响。结果表明，在干旱15天（15 d）时间点，幼苗和幼龄个体的叶片光饱和净光合速率（A）值均下降（分别下降了-68.9%和-45.2%）。幼苗的内在水分利用效率（iWUE）显著低于对照组（-52.2%），但在幼龄个体中未观察到iWUE的差异。在干旱30天（30 d）时间点，幼苗的A值下降（-129.8%）是由生化抑制引起的，与对照组相比，潜在最大光化学速率（Fv/Fm，0.42）较低，而幼龄个体的A值下降（-52.3%）是由于气孔导度降低（g，-50.5%）。我们的结果表明，长期干旱会增加幼苗死亡的风险，因为相对有限的气孔调节能力可能会增加大规模栓塞的可能性，从而导致水力失效。
