Zhang Xuejie, Qin Hao, Kan Zhenchao, Liu Dan, Wang Bingxin, Fan Shoujin, Jiang Peipei
Key Lab of Plant Stress Research, College of Life Sciences, Shandong Normal University, Ji'nan, China.
Dongying Key Laboratory of Salt Tolerance Mechanism and Application of Halophytes, Dongying Institute, Shandong Normal University, Dongying, China.
Front Plant Sci. 2024 Jul 18;15:1436152. doi: 10.3389/fpls.2024.1436152. eCollection 2024.
Salinity and droughts are severe abiotic stress factors that limit plant growth and development. However, the differences and similarities of non-structural carbohydrates (NSCs) responses patterns of trees under the two stress conditions remain unclear.
We determined and compared the growth, physiology, and NSCs response patterns and tested the relationships between growth and NSCs concentrations (or pool size) of seedlings planted in field under drought and salt stress with different intensities and durations.
We found that drought and salt stress can inhibit the growth of , and tended to enhance its stress resistance by increasing proline concentration and leaf thickness or density but decreasing investment in belowground biomass in short-term stress. During short-term drought and salt stress, the aboveground organs showed different NSCs response characteristics, while belowground organs showed similar change characteristics: the starch (ST) and NSCs concentrations in the coarse roots decreased, while the ST and soluble sugar (SS) concentrations in the fine roots increased to enhance stress resistance and maintain water absorption function. As salt and drought stress prolonged, the belowground organs represented different NSCs response patterns: the concentrations of ST and SS in fine roots decreased as salt stress prolonged; while ST in fine roots could still be converted into SS to maintain water absorption as drought prolonged, resulting in an increase of SS and a decrease of ST. Significant positive relationships were found between growth and the SS and total NSCs concentrations in leaves and branches, however, no significant correlations were found between growth and below-ground organs. Moreover, relationships between growth and NSCs pool size across organs could be contrast.
Our results provide important insights into the mechanisms of carbon balance and carbon starvation and the relationship between tree growth and carbon storage under stress, which were of great significance in guiding for the management of artificial forest ecosystem under the context of global change.
盐度和干旱是限制植物生长发育的严重非生物胁迫因素。然而，树木在这两种胁迫条件下非结构性碳水化合物（NSCs）响应模式的异同仍不清楚。
我们测定并比较了不同强度和持续时间的干旱和盐胁迫下田间种植幼苗的生长、生理和NSCs响应模式，并测试了生长与NSCs浓度（或库大小）之间的关系。
我们发现干旱和盐胁迫会抑制[具体树种]的生长，[具体树种]倾向于通过在短期胁迫中增加脯氨酸浓度、叶片厚度或密度，但减少地下生物量投资来增强其抗逆性。在短期干旱和盐胁迫期间，地上器官表现出不同的NSCs响应特征，而地下器官表现出相似的变化特征：粗根中的淀粉（ST）和NSCs浓度降低，而细根中的ST和可溶性糖（SS）浓度增加以增强抗逆性并维持吸水功能。随着盐和干旱胁迫的延长，地下器官呈现出不同的NSCs响应模式：随着盐胁迫延长，细根中ST和SS的浓度降低；而随着干旱延长，细根中的ST仍可转化为SS以维持吸水，导致SS增加而ST减少。在叶片和枝条的生长与SS和总NSCs浓度之间发现了显著的正相关关系，然而，在生长与地下器官之间未发现显著相关性。此外，各器官间生长与NSCs库大小的关系可能相反。
我们的研究结果为胁迫下碳平衡和碳饥饿机制以及树木生长与碳储存之间的关系提供了重要见解，这对于指导全球变化背景下人工林生态系统的管理具有重要意义。
