Basal Oqba, Zargar Tahoora Batool, Veres Szilvia
Department of Applied Plant Biology, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary.
Sci Rep. 2024 Jan 25;14(1):2200. doi: 10.1038/s41598-024-52838-2.
The global production of soybean, among other drought-susceptible crops, is reportedly affected by drought periods, putting more pressure on food production worldwide. Drought alters plants' morphology, physiology and biochemistry. As a response to drought, reactive oxygen species (ROS) concentrations are elevated, causing cellular damage. However, lower concentrations of ROS were reported to have an alleviating role through up-regulating various defensive mechanisms on different levels in drought-stressed plants. This experiment was set up in a controlled environment to monitor the effects of exogenous spray of different (0, 1, 5 and 10 mM) concentrations of HO on two soybean genotypes, i.e., Speeda (drought-tolerant), and Coraline (drought-susceptible) under severe drought stress conditions (induced by polyethylene glycol) during flowering stage. Furthermore, each treatment was further divided into two groups, the first group was kept under drought, whereas drought was terminated in the second group at the end of the flowering stage, and the plants were allowed to recover. After 3 days of application, drought stress significantly decreased chlorophyll-a and chlorophyll-b, total carotenoids, stomatal conductance, both optimal and actual photochemical efficiency of PSII (Fv/Fm and Df/Fm, respectively), relative water content, specific leaf area, shoot length and dry weight, and pod number and fresh weight, but significantly increased the leaf concentration of both proline and total soluble sugars, the root length, volume and dry weight of both genotypes. The foliar application of 1 mM and 5 mM HO on Speeda and Coraline, respectively enhanced most of the decreased traits measurably, whereas the 10 mM concentration did not. The group of treatments where drought was maintained after flowering failed to produce pods, regardless of HO application and concentration, and gradually deteriorated and died 16 and 19 days after drought application on Coraline and Speeda, respectively. Overall, Speeda showed better performance under drought conditions. Low concentrations of foliar HO could help the experimented soybean genotypes better overcome the influence of severe drought during even sensitive stages, such as flowering. Furthermore, our findings suggest that chlorophyll fluorescence and the cellular content of proline and soluble sugars in the leaves can provide clear information on the influence of both drought imposition and HO application on soybean plants.
据报道，包括大豆在内的其他易受干旱影响的作物的全球产量受到干旱期的影响，给全球粮食生产带来了更大压力。干旱会改变植物的形态、生理和生化特性。作为对干旱的响应，活性氧（ROS）浓度会升高，从而导致细胞损伤。然而，据报道，较低浓度的ROS通过上调干旱胁迫植物不同水平的各种防御机制而具有缓解作用。本实验在可控环境中进行，以监测在开花期严重干旱胁迫条件下（由聚乙二醇诱导），外源喷施不同浓度（0、1、5和10 mM）的过氧化氢（HO）对两种大豆基因型，即Speeda（耐旱型）和Coraline（干旱敏感型）的影响。此外，每个处理进一步分为两组，第一组保持干旱状态，而第二组在开花期末期解除干旱，让植株恢复生长。喷施3天后，干旱胁迫显著降低了叶绿素a和叶绿素b、总类胡萝卜素、气孔导度、PSII的最佳和实际光化学效率（分别为Fv/Fm和Df/Fm）、相对含水量、比叶面积、茎长和干重以及荚果数和鲜重，但显著增加了脯氨酸和总可溶性糖的叶片浓度、两种基因型的根长、根体积和根干重。分别在Speeda和Coraline上叶面喷施1 mM和5 mM的HO，可显著提高大部分下降的性状，而10 mM浓度则没有这种效果。开花后维持干旱的处理组，无论是否喷施HO及其浓度如何，均未结荚，并分别在对Coraline和Speeda施加干旱后的16天和19天逐渐枯萎死亡。总体而言，Speeda在干旱条件下表现更好。低浓度的叶面HO可以帮助受试大豆基因型在甚至像开花这样的敏感阶段更好地克服严重干旱的影响。此外，我们的研究结果表明，叶绿素荧光以及叶片中脯氨酸和可溶性糖的细胞含量可以提供关于干旱胁迫和HO喷施对大豆植株影响的清晰信息。
