Drought immediately increases soluble sugar and decreases starch in seedlings of the shade-tolerant compared to the sun-tolerant ecotype of Paubrasilia echinata

IF 1.7 4区生物学 Q3 ECOLOGY

Flora Pub Date : 2025-02-21 DOI:10.1016/j.flora.2025.152701

Geraldo Rogério Faustini Cuzzuol , Carlos Luis Sánchez Fonseca , Moemy Gomes de Moraes , Bernardo Pretti Becacici Macieira

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引用次数: 0

Abstract

How shade-tolerant and sun-tolerant plants will respond to the predicted increase in drought for tropical forests by the end of this century is a subject of global interest. One of the physiological defense mechanisms of plants against the harmful effects of drought is their ability to adjust their contents of non-structural carbohydrates – NSC (soluble sugars and starch) and cell wall polymers – CWP (hemicelluloses, cellulose, and lignin). As a research model, we used plants of the small leaf (shade-tolerant) and medium leaf (sun-tolerant) ecotypes of Paubrasilia echinata, a tree native to the Atlantic Forest of Brazil. The plants were subjected to drought (no watering) for 17 days when the water potential (Ψ_w) of the leaves reached -3 MPa. Then, they were watered daily (rehydration) for 36 days. In different periods, we evaluated the NSC and CWP contents of their leaves, stem, and roots. Intraspecific similarities and divergences occurred in the contents of these molecules. The shade-tolerant ecotype showed immediate responses to drought by raising the soluble sugar and hemicelluloses, and decreasing the starch contents (aerial organs). The lignin content increased in the aerial organs of both ecotypes and the cellulose content more in the sun-tolerant ecotype. After rehydration, the NSC and CWP contents of the two ecotypes were equal to their controls. We concluded that the shade-tolerant ecotype showed greater sensitivity to drought by demonstrating a greater need for NSC and hemicelluloses adjustments at the beginning of the drought. However, the drought did not affect the survival of the two ecotype's plants. If climate change forecasts for the southeastern region of Brazil prevail in the coming decades, natural or planted seedlings of the shade-tolerant ecotype of P. echinata may suffer greater consumption of its transient energy reservoir (starch). Such responses can compromise the functioning of their seedlings if droughts become more intense and frequent.

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与耐阳光生态型的刺桐相比，干旱会立即增加遮荫型幼苗的可溶性糖和减少淀粉

到本世纪末，耐阴和耐日照的植物将如何应对预计热带森林干旱的增加，这是一个全球感兴趣的主题。植物对干旱有害影响的生理防御机制之一是调节其非结构性碳水化合物- NSC（可溶性糖和淀粉）和细胞壁聚合物- CWP（半纤维素、纤维素和木质素）含量的能力。本研究以巴西大西洋森林原生树种Paubrasilia echinata的小叶（耐阴）和中叶（耐日照）生态型植物为研究对象。当叶片水势（Ψw）达到-3 MPa时，进行干旱（不浇水）处理17 d。然后，连续36天每天给它们浇水（补充水分）。在不同时期，我们对其叶、茎和根的NSC和CWP含量进行了测定。这些分子的含量在种内具有相似性和差异性。耐阴生态型通过提高可溶性糖和半纤维素含量，降低淀粉含量（空气器官），对干旱表现出直接的响应。两种生态型的空气器官中木质素含量增加，耐晒生态型的纤维素含量增加。复水后，两生态型的NSC和CWP含量与对照相当。我们得出结论，耐阴生态型对干旱的敏感性更强，在干旱开始时对NSC和半纤维素的调节需求更大。然而，干旱并没有影响这两种生态型植物的生存。如果对巴西东南部地区的气候变化预测在未来几十年得到证实，那么耐阴生态型的紫锥菊的天然或人工幼苗可能会消耗更多的瞬时能量库（淀粉）。如果干旱变得更加强烈和频繁，这种反应可能会损害其幼苗的功能。

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来源期刊

Flora 生物-植物科学

CiteScore

3.30

自引率

10.50%

发文量

130

审稿时长

54 days

期刊介绍： FLORA publishes original contributions and review articles on plant structure (morphology and anatomy), plant distribution (incl. phylogeography) and plant functional ecology (ecophysiology, population ecology and population genetics, organismic interactions, community ecology, ecosystem ecology). Manuscripts (both original and review articles) on a single topic can be compiled in Special Issues, for which suggestions are welcome. FLORA, the scientific botanical journal with the longest uninterrupted publication sequence (since 1818), considers manuscripts in the above areas which appeal a broad scientific and international readership. Manuscripts focused on floristics and vegetation science will only be considered if they exceed the pure descriptive approach and have relevance for interpreting plant morphology, distribution or ecology. Manuscripts whose content is restricted to purely systematic and nomenclature matters, to geobotanical aspects of only local interest, to pure applications in agri-, horti- or silviculture and pharmacology, and experimental studies dealing exclusively with investigations at the cellular and subcellular level will not be accepted. Manuscripts dealing with comparative and evolutionary aspects of morphology, anatomy and development are welcome.