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干旱胁迫对疏叶骆驼刺幼苗生长和生理的影响

摘要: 叶片和根系能通过形态、生理和生物量累积的变化响应干旱胁迫。以策勒绿洲-沙漠过渡带的优势植物 疏叶骆驼刺(Alhagi sparsifolia Shap.)为研究对象,通过盆栽试验模拟3种水分条件(充分灌溉CK:土壤含水量占最大 田间持水量的70%~75%;轻度胁迫W1:田间持水量的50%~55%;重度胁迫W2:田间持水量的25%~30%),分析一年 生骆驼刺幼苗叶片和根系生长、生理的变化特征,揭示骆驼刺对干旱胁迫的适应策略。结果表明:(1)干旱显著抑 制骆驼刺地上和地下各器官生长,主要表现为:叶面积、根长、根表面积、根组织密度以及叶和根的可溶性糖含量显 著减小(P<0.05);叶组织密度、叶干物质含量、比根长以及叶和根的脯氨酸、丙二醛含量增大。(2)生长前期,各处理 地上生物量均占比较大(CK、W1、W2下根冠比分别为0.430.14、0.590.1、0.830.83);而生长后期各处理地下生物 量占比较大,其中重度胁迫下根冠比最大(3.120.32),表明骆驼刺在生长后期增强了地下部分的资源投入,且这种 资源分配特征在重度干旱胁迫下更明显。(3)Pearson相关性分析表明,骆驼刺叶形态与根生理相关的核心性状存 在显著的权衡关系(P<0.05),同时叶与根在生理代谢上能够协同变化。初步说明,骆驼刺幼苗在干旱下表现出干 物质储存和防御能力高、水分消耗低的适应特征,能够协调叶片和根系的资源分配关系,随胁迫时间的增加逐步形 成缓慢投资、保守生长的策略。该结果为该区域荒漠植被恢复和管理提供参考。

Abstract: Leaves and roots respond to drought stress through morphological, physiological, and biomass accumulation changes. Alhagi sparsifolia is the dominant plant in the desert- oasis transition zone of Cele. We analyzed the characteristics of growth and physiological changes in leaves and roots of 1-year-old A. sparsifolia seedlings through a pot experiment. Results revealed the adaptive strategy of A. sparsifolia to drought stress. We simulated three water conditions (CK is well- watered: 70%-75% field capacity (FC); W1 is mild stress: 50%- 55% FC; W2 is severe stress: 25%-30% FC). The results show the following: (1) Drought significantly inhibited the growth of the aboveground and underground tissues of A. sparsifolia. The main manifestations are: leaf area, root length, root surface area, root tissue density, and soluble sugar content of leaves and roots decreased significantly under stress (P < 0.05). The leaf tissue density, leaf dry matter content, specific root length, proline and malondialdehyde contents of leaf and root increased. (2) In the early growth stage, the aboveground biomass of A. sparsifolia under all treatments was relatively high (root-shoot ratios under CK, W1, and W2 were 0.43 0.14, 0.59 0.1, and 0.83 0.83), while in the late growth stage, the below-ground biomass under all treatments was relatively high. The root-shoot ratio was the highest under severe stress (3.12 0.32). The results indicate that A. sparsifolia enhanced the investment of resources underground in the late growth stage, and the resource allocation characteristic is more obvious under severe drought stress. (3) Pearson-correlation analysis showed that there was a significant tradeoff between core traits related to leaf morphology and root physiology in A. sparsifolia (P < 0.05). Meanwhile, the leaf and root had synergistic changes in physiological metabolism. The results preliminary indicate the adaptive characteristics and A. sparsifolia seedlings under drought exhibit high dry matter storage, defense capacity, and low water consumption. A. sparsifolia can coordinate the resource allocation relationship between leaves and roots. At the same time, with drought stress time increased, the adaptive strategy of slow investment and conservative growth of A. sparsifolia was gradually formed. The results provide a reference for the restoration and management of desert vegetation in this region.

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[V1] 2023-03-13 17:49:43 ChinaXiv:202303.00130V1 下载全文
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