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干旱胁迫下藏东南沙生植物非结构性碳水化合物分配策略研究

Study on non-structural carbohydrate allocation strategies of psammophytes induced by drought stress in southeastern Xizang

  • 摘要: 植物各组织中的非结构性碳水化合物(Non-structural carbohydrates,NSC)含量能反映植物对能量物质的分配策略,揭示干旱胁迫下植物NSC的动态变化有助于了解干旱环境下植物生存的资源分配策略。本研究以藏东南地区两种沙生植物白莲蒿(Artemisia gmelinii Weber)和云南沙棘(Hippophae rhamnoides subsp. yunnanensis Rousi)为研究对象,探讨在不同程度干旱胁迫下植物各器官(叶片、枝条、粗根、细根)中的非结构性碳水化合物含量的分配动态。结果显示:(1)干旱胁迫导致植物的根冠比显著增加,枝条、粗根和细根中的可溶性糖和NSC含量亦随干旱胁迫强度的增加而增加;(2)干旱胁迫发生后,NSC及其组分优先被分配至地下部位,叶片和细根中的NSC主要以可溶性糖的形式累积;(3)干旱胁迫下,白莲蒿细根的可溶性糖、淀粉及NSC的占比随干旱胁迫强度的增加而降低,而云南沙棘则与之相反。研究结果表明,植物通过储存更多的可溶性糖来抵御干旱胁迫,并且主动将NSC储存至根部来提升植物应对干旱的能力。

     

    Abstract: The content of non-structural carbohydrates (NSC) in different plant tissues reflects the energy allocation strategies within plant individuals. Understanding the dynamic changes in NSC under drought stress can provide insights into how plants manage resource distribution in drought conditions. In this study, two psammophyte species from southeastern Xizang (Artemisia gmelinii Weber and Hippophae rhamnoides subsp. Yunnanensis Rousi) were selected to explore the distribution dynamics of NSC in different organs (leaves, branches, coarse roots, and fine roots) under varying drought intensities. Results showed that: (1) Intensified drought stress significantly increased the root-to-shoot ratio and the accumulation of soluble sugars and NSC in branches, coarse roots, and fine roots; (2) Under drought stress, there was a preferential allocation of NSC to underground parts, with leaves and fine roots primarily accumulating NSC in the form of soluble sugars; (3) In the fine roots of A. gmelinii, the proportion of soluble sugars, starch, and NSC decreased with intensifying drought, whereas in H. yunnanensis, the proportion of soluble sugars, starch, and NSC increased with intensifying drought. This study suggests that plants mitigate drought stress by storing more soluble sugars and enhance their drought resilience by allocating more NSC to the roots.

     

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