ABSTRACT

Soil water availability and light are abiotic factors that may be plant stressors when they are subjected to unfavorable conditions and may limit their metabolism and trigger protection mechanisms. The aim of this study was to evaluate morphological and metabolic strategies in Cedrela fissilis seedlings that enable their survival and resilience when subjected to flooding and shading. The seedlings were cultivated under flooding for 0, 10, 20, 30, and 40 days or received only rainwater (control: 120 mm distributed over 35 evaluation days with a daily maximum of 28 mm). Flooding treatments were conducted under 70%, 30%, and 0% shading. Cedrela fissilis seedlings presented plasticity in physiological and morphological responses to flooding and shading, which indicates that this species has the potential for survival in the evaluated environments. The seedlings were tolerant to flooding for up to 40 days, regardless of light availability, although 70% shading minimized the stressful effects of flooding. The formation of lenticels, adventitious roots, and the increased activity of antioxidant enzymes from the 20^th day of flooding favored the resilience of photosynthetic metabolism.

摘要

土壤水分有效性和光照是非生物因素，当植物处于不利条件下时可能成为植物应激源，并可能限制其新陈代谢并触发保护机制。本研究的目的是评估Cedrela fissilis幼苗的形态学和代谢策略，使它们在遭受洪水和阴影时能够生存和恢复。幼苗在洪水下培养 0、10、20、30 和 40 天或仅接受雨水（对照：120 毫米分布在 35 个评估日，每日最大雨量为 28 毫米）。淹没处理在 70%、30% 和 0% 遮光度下进行。雪松幼苗在对洪水和阴影的生理和形态反应中表现出可塑性，这表明该物种具有在评估环境中生存的潜力。无论光照情况如何，这些幼苗都能耐受长达 40 天的洪水，尽管 70% 的遮荫可以最大限度地减少洪水的压力影响。^{从淹水第 20 天开始，皮孔}、不定根的形成和抗氧化酶活性的增加有利于光合代谢的恢复。