Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, China.
Agricultural Experiment Station of Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, China.
Int J Mol Sci. 2018 Jun 29;19(7):1913. doi: 10.3390/ijms19071913.
Here, we investigated the effects of selenium (Se) applications on two strawberry varieties, Akihime and Benihoppe, under chilling stress and recovery conditions. Changes in photosynthetic parameters, antioxidant enzyme activities, ascorbate (AsA)-glutathione (GSH) cycle-related enzyme activities, and low-molecular-mass antioxidant contents were determined. Foliar spraying with Se alleviated the decline in the net photosynthetic rate and chlorophyll content and increased the malondialdehyde and hydrogen peroxide contents of strawberry seedlings’ leaves under chilling stress. As the time under chilling stress increased, the stomatal conductance decreased and intercellular CO₂ concentration increased, suggesting that nonstomatal factors had major limiting effects on the net photosynthetic rate’s decrease. Se applications significantly alleviated the adverse impacts of chilling stress on changes in stomatal conductance and intercellular CO₂ concentration. Se, especially at lower concentrations, significantly increased superoxide dismutase, catalase, and peroxide enzyme activities during chilling stress. Approximately 5 mg·L of sodium selenite solution had the greatest stress-alleviating effects. Among the AsA-GSH cycle-related enzymes, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase (MDHAR) treatments, coupled with an appropriate dose of Se, significantly enhanced ascorbate peroxidase and MDHAR activities, which suggested that Se applications played important roles in strawberry leaves by affecting AsA-GSH cycle-related defenses against the oxidative damage caused by chilling stress. Furthermore, MDHAR was the key enzyme required to maintain the balance between AsA consumption and regeneration that may assist in protecting strawberry seedlings in a low-temperature environment.
在这里，我们研究了在冷藏胁迫和恢复条件下，硒（Se）应用对两个草莓品种（Akihime 和 Benihoppe）的影响。测定了光合作用参数、抗氧化酶活性、抗坏血酸（AsA）-谷胱甘肽（GSH）循环相关酶活性和小分子抗氧化剂含量的变化。叶面喷施 Se 缓解了草莓幼苗叶片在冷藏胁迫下净光合速率和叶绿素含量的下降，并增加了丙二醛和过氧化氢的含量。随着冷藏胁迫时间的增加，气孔导度下降，胞间 CO₂浓度增加，表明非气孔因素对净光合速率下降有主要限制作用。Se 处理显著缓解了冷藏胁迫对气孔导度和胞间 CO₂浓度变化的不利影响。Se，特别是在较低浓度下，在冷藏胁迫下显著增加了超氧化物歧化酶、过氧化氢酶和过氧化物酶的活性。约 5 mg·L 的亚硒酸钠溶液具有最大的缓解胁迫作用。在 AsA-GSH 循环相关酶中，与适量 Se 处理相结合的抗坏血酸过氧化物酶、谷胱甘肽还原酶、脱氢抗坏血酸还原酶和单脱氢抗坏血酸还原酶（MDHAR）显著增强了抗坏血酸过氧化物酶和 MDHAR 的活性，这表明 Se 处理通过影响 AsA-GSH 循环相关防御来发挥重要作用，以抵御冷藏胁迫引起的氧化损伤。此外，MDHAR 是维持 AsA 消耗和再生平衡所需的关键酶，这可能有助于保护草莓幼苗在低温环境下。
