Guo Xinyi, Peng Changhui, Li Tong, Huang Jingjing, Song Hanxiong, Zhu Qiuan, Wang Meng
Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, China.
Department of Biology Sciences, Institute of Environment Sciences, University of Quebec at Montreal, P.O. Box 8888, Station Centre-Ville, Montreal, QC H3C 3P8, Canada.
Biology (Basel). 2021 Mar 30;10(4):281. doi: 10.3390/biology10040281.
Intense and frequent drought events strongly affect plant survival. Non-structural carbohydrates (NSCs) are important "buffers" to maintain plant functions under drought conditions. We conducted a drought manipulation experiment using three-year-old Carr. seedlings. The seedlings were first treated under different drought intensities (i.e., no irrigation, severe, and moderate) for 50 days, and then they were re-watered for 25 days to explore the dynamics of NSCs in the leaves, twigs, stems, and roots. The results showed that the no irrigation and severe drought treatments significantly reduced photosynthetic rate by 93.9% and 32.6% for 30 days, respectively, leading to the depletion of the starch storage for hydraulic repair, osmotic adjustment, and plant metabolism. The seedlings under moderate drought condition also exhibited starch storage consumption in leaves and twigs. After re-watering, the reduced photosynthetic rate recovered to the control level within five days in the severe drought group but showed no sign of recovery in the no irrigation group. The seedlings under the severe and moderate drought conditions tended to invest newly fixed C to starch storage and hydraulic repair instead of growth due to the "drought legacy effect". Our findings suggest the depletion and recovery of starch storage are important strategies for seedlings, and they may play key roles in plant resistance and resilience under environmental stress.
强烈且频繁的干旱事件严重影响植物的存活。非结构性碳水化合物（NSCs）是干旱条件下维持植物功能的重要“缓冲物质”。我们使用三年生的卡尔栎幼苗进行了干旱控制实验。首先将幼苗置于不同干旱强度（即不灌溉、重度和中度）下处理50天，然后再浇水25天，以探究叶片、嫩枝、茎和根中NSCs的动态变化。结果表明，不灌溉和重度干旱处理分别在30天内使光合速率显著降低了93.9%和32.6%，导致用于水力修复、渗透调节和植物代谢的淀粉储备耗尽。中度干旱条件下的幼苗在叶片和嫩枝中也表现出淀粉储备的消耗。重新浇水后，重度干旱组光合速率降低部分在五天内恢复到对照水平，但不灌溉组没有恢复迹象。由于“干旱遗留效应”，重度和中度干旱条件下的幼苗倾向于将新固定的碳用于淀粉储备和水力修复而非生长。我们的研究结果表明，淀粉储备的耗尽和恢复是幼苗的重要策略，它们可能在环境胁迫下植物的抗性和恢复力中发挥关键作用。
