College of Agriculture, Nanjing Agricultural University, No. 1 Weigang, Nanjing, Jiangsu, 210095, PR China.
College of Agriculture, Nanjing Agricultural University, No. 1 Weigang, Nanjing, Jiangsu, 210095, PR China; Department of Crop and Soil Sciences, University of Georgia, Tifton, GA, 31794, USA.
Plant Physiol Biochem. 2019 Jun;139:333-341. doi: 10.1016/j.plaphy.2019.03.038. Epub 2019 Mar 29.
Chronic elevated temperature and soil-waterlogging events often occur concomitantly in the Yangtze River Valley; however, a clear understanding of the effects of aforementioned co-occurring stresses on antioxidant defense in cotton has not been attained. To address this, two temperature conditions during the whole flowering and boll development periods, and three soil-waterlogging levels (0, 3, 6 d) starting on the day of anthesis were established. In the current study, no siginificant difference was observed on plant performance for 3 d soil-waterlogging, whereas 6 d soil-waterlogging event and elevated temperature in isolation negatively affected plant performance (i.e. leaf area declined by 33.3% and 14.7% in AW (soil waterlogging for 6 d under ambient temperature regime) and EC (soil well-watered (SRWC(75 ± 5) %) under elevated temperature for 2-3 °C) relative to AC (soil well-watered (SRWC(75 ± 5) %) under ambient temperature regime)) and induced ROS (reactive oxygen species) production and scavenging mechanisms in the subtending leaf of cotton. SOD (superoxide dismutase), CAT (catalase), and POX (peroxidase) activities were increased, and ASA (ascorbic acid) concentration was enhanced due to higher HO (hydrogen peroxide) and O accumulations. Whereas, APX (ascorbate peroxidase), DHAR (dehydroascorbate reductase) and GR (glutathione reductase) activities were inhibited under elevated temperature regime or waterlogging event, especially in the treatment of EW (soil waterlogging for 6 d under elevated temperature for 2-3 °C), which resulted in increasing HO concentration and higher O generation rate. However, plants acclimated to a short-term waterlogging stress (3 d) performed a cross tolerance to chronic elevated temperature regime (leaf number increased by 11.4%, whereas the abscission rate decreased by 4.6% in EW (soil waterlogging for 3 d under elevated temperature for 2-3 °C) compared with EC (soil well-watered (SRWC(75 ± 5) %) under elevated temperature for 2-3 °C)). Moreover, plants undergone a brief soil-waterlogging (3 d) induced higher GR activity and increased ASA concentration, along with enhanced SOD, CAT, POX activities, limiting HO and O accumulation and reducing oxidative damage to membrane lipids as evidenced by reduced MDA (malondialdehyde) concentration when cotton was subsequently exposed to chronic elevated temperature regime.
长江流域经常同时出现慢性高温和土壤积水事件；然而，对于上述并发胁迫对棉花抗氧化防御的影响，我们还没有清晰的认识。为了解决这个问题，在整个开花和棉铃发育期间设定了两个温度条件，并在开花当天开始设定三个土壤积水水平（0、3、6d）。在本研究中，3d 的土壤积水对植物生长没有显著影响，而单独的 6d 土壤积水和高温会对植物生长产生负面影响（即 AW（在环境温度下土壤积水 6d）中叶片面积比 AC（环境温度下土壤积水 6d）下降 33.3%和 14.7%，而 EC（在升高 2-3°C 的温度下土壤湿润（SRWC(75±5)%））中的叶片面积下降），并诱导棉花叶柄叶片中 ROS（活性氧）的产生和清除机制。SOD（超氧化物歧化酶）、CAT（过氧化氢酶）和 POX（过氧化物酶）活性增加，ASA（抗坏血酸）浓度因 HO（过氧化氢）和 O 积累而增加。然而，在高温或水淹条件下，APX（抗坏血酸过氧化物酶）、DHAR（脱氢抗坏血酸还原酶）和 GR（谷胱甘肽还原酶）活性受到抑制，特别是在 EW（在升高 2-3°C 的温度下土壤积水 6d）处理中，这导致 HO 浓度增加和 O 生成速率增加。然而，适应短期积水胁迫（3d）的植物对慢性高温胁迫表现出交叉耐受性（在 EW（在升高 2-3°C 的温度下土壤积水 3d）中叶片数增加 11.4%，而在 EC（在升高 2-3°C 的温度下土壤湿润（SRWC(75±5)%））中脱落率降低 4.6%）。此外，经历短暂土壤积水（3d）的植物会诱导更高的 GR 活性和增加的 ASA 浓度，同时增强 SOD、CAT、POX 活性，限制 HO 和 O 的积累，减少膜脂的氧化损伤，这表现在 MDA（丙二醛）浓度降低，当棉花随后暴露于慢性高温胁迫时。
