Semwal Vimal Kumar, Khanna-Chopra Renu
Stress Physiology Laboratory, Water Technology Centre, Indian Agricultural Research Institute, New Delhi, 110012 India.
Present Address: Africa Rice Center (AfricaRice), C/O IITA, PMB 5320, Oyo Road, Ibadan, Nigeria.
Physiol Mol Biol Plants. 2020 Jul;26(7):1331-1339. doi: 10.1007/s12298-020-00821-2. Epub 2020 Jun 10.
(common name Bathua) is a widely adapted weed plant facing wide array of temperatures (5-45 °C) during growth and development in North India. Antioxidant defense was studied in leaves under water deficit stress, heat stress, water deficit stress and heat stress combination and water deficit preconditioning followed by heat stress. plants subjected to water deficit stress and heat stress combination showed higher decline in water relations and lesser recovery compared to either stresses alone. Highest HO content, lipid peroxidation and protein damage were observed in plants experiencing water deficit stress and heat stress combination which was coupled with less induction in activities of SOD, CAT and all AsA-GSH cycles enzymes and decline in AsA and GSH pool compared to plants subjected to either stress alone. Water deficit preconditioned plants maintained higher activities of antioxidant defense enzymes and metabolites such as SOD, CAT, POX, DHAR, GSH content and AsA/DHA and GSH/GSSG ratios compared to non-preconditioned plants under heat stress. This is the first holistic report on effect of water deficit stress and heat stress combination and water deficit preconditioning followed by heat stress on ROS, damage and antioxidant defense including enzymes and metabolites in . Water deficit stress and heat stress combination was more detrimental in than either of the stresses alone as decline in water relations and increase in oxidative stress and damage was coupled with a decline in antioxidant defense both in enzymes i.e. SOD, CAT and AsA-GSH cycles enzymes and metabolites i.e. AsA and GSH content. Water deficit preconditioning followed by recovery resulted in induction of co-ordinated antioxidant defense in terms of both enzyme activities and metabolites during subsequent heat stress in . Enhanced CAT activity and higher redox pool played a major role in cross tolerance in water deficit preconditioned plants under heat stress.
（俗名菠菜）是一种适应性广泛的杂草植物，在印度北部生长发育期间面临多种温度范围（5 - 45°C）。研究了水分亏缺胁迫、热胁迫、水分亏缺胁迫与热胁迫组合以及水分亏缺预处理后再进行热胁迫下叶片的抗氧化防御。与单独的任何一种胁迫相比，遭受水分亏缺胁迫与热胁迫组合的植物水分关系下降幅度更大，恢复能力更弱。在经历水分亏缺胁迫与热胁迫组合的植物中观察到最高的过氧化氢含量、脂质过氧化和蛋白质损伤，与单独遭受任何一种胁迫的植物相比，其超氧化物歧化酶、过氧化氢酶和所有抗坏血酸 - 谷胱甘肽循环酶的活性诱导较少，抗坏血酸和谷胱甘肽库下降。与热胁迫下未预处理的植物相比，水分亏缺预处理的植物维持了较高的抗氧化防御酶和代谢物活性，如超氧化物歧化酶、过氧化氢酶、过氧化物酶、脱氢抗坏血酸还原酶、谷胱甘肽含量以及抗坏血酸/脱氢抗坏血酸和谷胱甘肽/氧化型谷胱甘肽比率。这是关于水分亏缺胁迫与热胁迫组合以及水分亏缺预处理后再进行热胁迫对活性氧、损伤以及包括酶和代谢物在内的抗氧化防御影响的第一份全面报告。水分亏缺胁迫与热胁迫组合对其的危害比单独的任何一种胁迫更大，因为水分关系下降、氧化应激和损伤增加，同时抗氧化防御在酶（即超氧化物歧化酶、过氧化氢酶和抗坏血酸 - 谷胱甘肽循环酶）和代谢物（即抗坏血酸和谷胱甘肽含量）方面都有所下降。水分亏缺预处理后再恢复导致在随后的热胁迫期间，在酶活性和代谢物方面都诱导了协同的抗氧化防御。增强的过氧化氢酶活性和更高的氧化还原库在水分亏缺预处理的植物在热胁迫下的交叉耐受性中起主要作用。
