Department of Crop Science, School of Agriculture, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana.
Department of Agroecology, Faculty of Technical Sciences, Aarhus University, Tjele, Denmark.
Sci Rep. 2024 Nov 15;14(1):28090. doi: 10.1038/s41598-024-79178-5.
The co-occurrence of drought and heat significantly hampers plant productivity. Although their impacts are well studied, these studies have been based on the effects of individual stressors rather than their combined influence. Okra is crucial for food and nutritional security and livelihoods in many regions, yet it remains under-researched and unimproved. Okra has been proven to be sensitive to both drought and heat stress. This study employed a cost-effective phenotyping method to assess key traits characterising the diversity of okra morphophysiological responses to independent and interactive heat-drought stresses. This study aimed to understand okra responses to stress, identify stress-resilient traits, and characterise okra genotypes. We also addressed the need to examine interactive stress effects, which mirror real-world scenarios more accurately than single-stress studies. Sixty-three okra genotypes were subjected to heat, drought, or concurrent heat-drought stress at the seedling stage in improvised climate-controlled chambers. The germplasm exhibited significant variations in response to the various stresses. The broad-sense heritability was high (> 0.60) for traits such as chlorophyll content, plant biomass, performance indices, electrolyte leakage, and total leaf area. Drought stress alone had a more pronounced effect than heat stress alone, and the adverse impact was worsened under combined heat and drought stress. The interactive impact of drought and heat was more likely additive than antagonistic or synergistic. A positive and strong relationship was observed between photosynthetic efficiency parameters such as the Fv/Fm ratio, chlorophyll content, relative water index, and biomass parameters such as dry shoot weight. The 63 okra genotypes were classified into three distinct clusters, suggesting potential for future breeding efforts. Okra genotype considered to be tolerant or climate resilient (such as GH170, V1060831, GH174, V1060874, and GH106) to drought and heat, maintained enhanced photosynthetic efficiency and high internal water potential, possibly reducing osmotic and oxidative damage. This study revealed some mechanisms underlying the adaptation of okra genotypes to independent and combined heat and drought stress. The results provide a basis for breeding efforts to develop climate-resilient okra varieties.
干旱和高温的同时发生严重阻碍了植物的生产力。尽管它们的影响已经得到了很好的研究，但这些研究都是基于单一胁迫因素的影响，而不是它们的综合影响。秋葵在许多地区对粮食和营养安全以及生计都至关重要，但它的研究仍然不足，也没有得到改善。秋葵已被证明对干旱和高温胁迫都很敏感。本研究采用了一种具有成本效益的表型分析方法，评估了秋葵形态生理对独立和相互热干旱胁迫的多样性的关键特征。本研究旨在了解秋葵对胁迫的反应，确定具有抗胁迫特性的特征，并描述秋葵基因型。我们还解决了需要研究交互胁迫效应的问题，因为与单一胁迫研究相比，这种效应更能准确反映现实世界的情况。在改良的气候控制室内，在幼苗期，63 个秋葵基因型分别受到热、干旱或热干旱胁迫的处理。种质对各种胁迫的反应表现出显著的差异。叶绿素含量、植物生物量、性能指数、电解质渗漏和总叶面积等性状的广义遗传力均较高（>0.60）。单独的干旱胁迫比单独的热胁迫影响更大，而在热和干旱胁迫同时存在的情况下，不利影响则更加严重。干旱和热胁迫的交互影响更可能是相加的，而不是拮抗的或协同的。光合效率参数（如 Fv/Fm 比值、叶绿素含量、相对水指数）与生物量参数（如干茎重）之间存在着正强的关系。63 个秋葵基因型被分为三个不同的聚类，这表明未来有进行育种工作的潜力。一些秋葵基因型被认为对干旱和高温具有耐受性或气候适应性（如 GH170、V1060831、GH174、V1060874 和 GH106），它们保持了较高的光合效率和内部水势，可能降低了渗透和氧化损伤。本研究揭示了秋葵基因型对独立和综合热干旱胁迫适应的一些机制。研究结果为培育耐旱耐热的秋葵品种提供了基础。
