Elkelish Amr, El-Mogy Mohamed M, Niedbała Gniewko, Piekutowska Magdalena, Atia Mohamed A M, Hamada Maha M A, Shahin Mostafa, Mukherjee Soumya, El-Yazied Ahmed Abou, Shebl Mohamed, Jahan Mohammad Shah, Osman Ali, El-Gawad Hany G Abd, Ashour Hatem, Farag Reham, Selim Samy, Ibrahim Mohamed F M
Botany Department, Faculty of Science, Suez Canal University Ismailia, Ismailia 41522, Egypt.
Vegetable Crops Department, Faculty of Agriculture, Cairo University, Giza 12613, Egypt.
Plants (Basel). 2021 Oct 28;10(11):2318. doi: 10.3390/plants10112318.
Cysteine (Cys) and α-lipoic acid (ALA) are naturally occurring antioxidants (sulfur-containing compounds) that can protect plants against a wide spectrum of environmental stresses. However, up to now, there are no conclusive data on their integrative roles in mitigation of drought stress in wheat plants. Here, we studied the influence of ALA at 0.02 mM (grain dipping pre-cultivation treatment) and Cys (25 and 50 ppm as a foliar application) under well watered and deficit irrigation (100% and 70% of recommended dose). The results showed that deficit irrigation markedly caused obvious cellular oxidative damage as indicated by elevating the malondialdehyde (MDA) and hydrogen peroxide content (HO). Moreover, water stressed plants exhibited multiple changes in physiological metabolism, which affected the quantitative and qualitative variables of grain yield. The enzymatic antioxidants, including superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POX) were improved by Cys application. SOD and APX had the same response when treated with ALA, but CAT and POX did not. Moreover, both studied molecules stimulated chlorophyll (Chl) and osmolytes' biosynthesis. In contrast, the Chl a/b ratio was decreased, while flavonoids were not affected by either of the examined molecules. Interestingly, all above-mentioned changes were associated with an improvement in the scavenging capacity of reactive oxygen species (ROS), leaf relative water content (RWC), grain number, total grain yield, weight of 1000 kernels, gluten index, falling number, and alveographic parameters (P, W, and P/L values). Furthermore, heatmap plot analysis revealed several significant correlations between different studied parameters, which may explore the importance of applied Cys and ALA as effective compounds in wheat cultivation under water deficit conditions.
半胱氨酸（Cys）和α-硫辛酸（ALA）是天然存在的抗氧化剂（含硫化合物），可保护植物免受多种环境胁迫。然而，到目前为止，关于它们在缓解小麦植株干旱胁迫中的综合作用尚无确凿数据。在此，我们研究了在充分灌溉和亏缺灌溉（推荐剂量的100%和70%）条件下，0.02 mM的ALA（浸种预培养处理）和Cys（25 ppm和50 ppm叶面喷施）的影响。结果表明，亏缺灌溉显著导致明显的细胞氧化损伤，表现为丙二醛（MDA）和过氧化氢含量（HO）升高。此外，水分胁迫植株在生理代谢方面表现出多种变化，影响了籽粒产量的数量和质量变量。施用Cys可提高包括超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）、过氧化氢酶（CAT）和过氧化物酶（POX）在内的酶促抗氧化剂活性。用ALA处理时，SOD和APX有相同的反应，但CAT和POX没有。此外，所研究的两种分子均刺激了叶绿素（Chl）和渗透调节物质的生物合成。相比之下，Chl a/b比值降低，而黄酮类化合物不受所研究的任何一种分子的影响。有趣的是，上述所有变化都与活性氧（ROS）清除能力、叶片相对含水量（RWC）、籽粒数、总籽粒产量、千粒重、面筋指数、降落数值和粉质仪参数（P、W和P/L值）的改善有关。此外，热图分析揭示了不同研究参数之间的几个显著相关性，这可能揭示了施用Cys和ALA作为水分亏缺条件下小麦栽培中有效化合物的重要性。
