To study the possibility of increasing the drought tolerance of common bean with the exogenous application of 24-epibrassinolide (EBL), an experiment was conducted in 2016 and 2017. In this experiment, two irrigation levels (optimal irrigation and drought stress) were applied to the main plots and two common bean genotypes (Kusha cultivar and COS16 genotype) and four EBL concentrations (0, 2, 4, and 6 μM) were allocated to sub-plots as factorial. In the flowering stage, drought stress was applied and plants were sprayed with EBL. The results showed that drought stress reduced relative water content (RWC) and increased proline content, malondialdehyde (MDA) content, and antioxidant enzymes activity. However, exogenous application of EBL reduced the seed yield loss and increased the drought stress tolerance in both common bean genotypes by decreasing the MDA content and increasing the RWC, proline content, antioxidant enzymes activity, and nitrate reductase activity. It can be concluded that foliar spray of 4 µM EBL as the best concentration may increase the seed yield and enhance the drought stress tolerance of common bean. Also, Cu/Zn-SOD was up-regulated in response to the drought stress and exogenous EBL. The COS16 genotype showed better response to the drought stress and exogenous EBL than the Kusha cultivar, because of the higher up-regulation of Cu/Zn-SOD in this genotype compared to the Kusha cultivar. Therefore, EBL can be used as a plant growth regulator to enhance drought stress tolerance and minimize the seed yield loss of common bean caused by water deficit.

中文翻译：

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研究施用24-表油菜素内酯对菜豆Cu/Zn-SOD表达和耐旱性的影响。


为了研究外源施用24-表油菜素内酯（EBL）提高菜豆耐旱性的可能性，于2016年和2017年进行了一项试验。在该试验中，采用了两种灌溉水平（最佳灌溉和干旱胁迫）主图和两种常见豆类基因型（Kusha 品种和 COS16 基因型）和四种 EBL 浓度（0、2、4 和 6 μM）作为因子分配到子图。在开花期，施加干旱胁迫并向植物喷洒EBL。结果表明，干旱胁迫降低了相对水分含量（RWC），增加了脯氨酸含量、丙二醛（MDA）含量和抗氧化酶活性。然而，外源EBL的施用通过降低MDA含量并增加RWC、脯氨酸含量、抗氧化酶活性和硝酸还原酶活性，减少了两种常见菜豆基因型的种子产量损失并提高了干旱胁迫耐受性。由此可见，叶面喷施4μM EBL为最佳浓度可提高菜豆种子产量，增强菜豆的干旱胁迫耐受性。此外， Cu/Zn - SOD在干旱胁迫和外源 EBL 的作用下上调。 COS16 基因型比 Kusha 品种对干旱胁迫和外源 EBL 表现出更好的响应，因为与 Kusha 品种相比，该基因型中Cu/Zn - SOD的上调更高。因此，EBL可作为植物生长调节剂，增强对干旱胁迫的耐受性，最大限度地减少菜豆因水分亏缺而造成的种子产量损失。