Rahman Md Mezanur, Mostofa Mohammad Golam, Das Ashim Kumar, Anik Touhidur Rahman, Keya Sanjida Sultana, Ahsan S M, Khan Md Arifur Rahman, Ahmed Minhaz, Rahman Md Abiar, Hossain Md Motaher, Tran Lam-Son Phan
Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA.
Department of Biochemistry and Molecular Biology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh.
Antioxidants (Basel). 2022 Mar 8;11(3):516. doi: 10.3390/antiox11030516.
Drought is a major environmental threat to agricultural productivity and food security across the world. Therefore, addressing the detrimental effects of drought on vital crops like soybean has a significant impact on sustainable food production. Priming plants with organic compounds is now being considered as a promising technique for alleviating the negative effects of drought on plants. In the current study, we evaluated the protective functions of ethanol in enhancing soybean drought tolerance by examining the phenotype, growth attributes, and several physiological and biochemical mechanisms. Our results showed that foliar application of ethanol (20 mM) to drought-stressed soybean plants increased biomass, leaf area per trifoliate, gas exchange features, water-use-efficiency, photosynthetic pigment contents, and leaf relative water content, all of which contributed to the improved growth performance of soybean under drought circumstances. Drought stress, on the other hand, caused significant accumulation of reactive oxygen species (ROS), such as superoxide and hydrogen peroxide, and malondialdehyde, as well as an increase of electrolyte leakage in the leaves, underpinning the evidence of oxidative stress and membrane damage in soybean plants. By comparison, exogenous ethanol reduced the ROS-induced oxidative burden by boosting the activities of antioxidant enzymes, including peroxidase, catalase, glutathione -transferase, and ascorbate peroxidase, and the content of total flavonoids in soybean leaves exposed to drought stress. Additionally, ethanol supplementation increased the contents of total soluble sugars and free amino acids in the leaves of drought-exposed plants, implying that ethanol likely employed these compounds for osmotic adjustment in soybean under water-shortage conditions. Together, our findings shed light on the ethanol-mediated protective mechanisms by which soybean plants coordinated different morphophysiological and biochemical responses in order to increase their drought tolerance.
干旱是全球农业生产力和粮食安全面临的主要环境威胁。因此，应对干旱对大豆等重要作物的不利影响对可持续粮食生产具有重大意义。用有机化合物对植物进行预处理目前被认为是一种减轻干旱对植物负面影响的有前景的技术。在本研究中，我们通过检测表型、生长特性以及几种生理生化机制，评估了乙醇在增强大豆耐旱性方面的保护作用。我们的结果表明，对遭受干旱胁迫的大豆植株进行叶面喷施乙醇（20 mM）可增加生物量、每三出复叶的叶面积、气体交换特征、水分利用效率、光合色素含量以及叶片相对含水量，所有这些都有助于提高大豆在干旱条件下的生长性能。另一方面，干旱胁迫导致活性氧（ROS）如超氧化物和过氧化氢以及丙二醛大量积累，同时叶片中电解质渗漏增加，这证明了大豆植株存在氧化应激和膜损伤。相比之下，外源乙醇通过提高抗氧化酶（包括过氧化物酶、过氧化氢酶、谷胱甘肽 - 转移酶和抗坏血酸过氧化物酶）的活性以及干旱胁迫下大豆叶片中总黄酮的含量，减轻了ROS诱导的氧化负担。此外，补充乙醇增加了干旱处理植株叶片中总可溶性糖和游离氨基酸的含量，这意味着乙醇可能利用这些化合物在缺水条件下对大豆进行渗透调节。总之，我们的研究结果揭示了乙醇介导的保护机制，通过该机制大豆植株协调不同的形态生理和生化反应以提高其耐旱性。
