College of Horticulture, Shanxi Agricultural University, Jinzhong 030801, Shanxi, China.
College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2023 Jan;34(1):151-159. doi: 10.13287/j.1001-9332.202301.015.
To understand the mitigation effects of melatonin on the chilling-induced photoinhibition in tomato, four groups of seedlings were labelled: NW (normal temperature + water), NM (normal temperature + melatonin), CW (chilling + water) and CM (chilling+ melatonin). We measured chlorophyll fluorescence, key photosynthetic parameters and the cycle efficiency for chloroplast ascorbic acid-glutathione (AsA-GSH). The results showed that, compared with the NW control, photosynthesis rate in CW was decreased by 50.3%-72.6%, chloroplast malondialdehyde content was decreased by 17.5%-132.7%, superoxide anion production was increased by 86.5%-235.9%, and HO was increased by 96.6%-208.4%. These trends were significantly alleviated by exogenous melatonin, with photosynthetic rates in CM being increased by 22.7%-24.7% compared with in CW, malondialdehyde content being decreased by 16.6%-29.0%, the rate of superoxide anion production being decreased by 14.9%-22.7%, HO content being decreased by 10.7%-27.1%. Compared with CW, the quantum yield of photochemical energy in PS Ⅱ was increased by 15.8% in CM, the quantum yield of regulated non-photochemical energy loss was increased by 7.2%, the quantum yield of non-regulated non-photochemical energy loss was decreased by 24.7%, and the activities of key metabolic enzymes in the AsA-GSH cycle were increased to different degrees. We concluded that exogenous melatonin application could alleviate photoinhibition in tomato seedlings under chilling by balancing the partitioning of absorption energy in PS Ⅱ and by enhancing the ROS scavenging efficiency of the AsA-GSH cycle in the chloroplast.
为了了解褪黑素对番茄低温胁迫诱导光抑制的缓解作用，我们将四组幼苗标记为：NW（正常温度+水）、NM（正常温度+褪黑素）、CW（低温+水）和 CM（低温+褪黑素）。我们测量了叶绿素荧光、关键光合作用参数和叶绿体抗坏血酸-谷胱甘肽（AsA-GSH）的循环效率。结果表明，与 NW 对照相比，CW 中的光合作用速率降低了 50.3%-72.6%，叶绿体丙二醛含量降低了 17.5%-132.7%，超氧阴离子产生增加了 86.5%-235.9%，HO 增加了 96.6%-208.4%。这些趋势在外源褪黑素的作用下得到显著缓解，CM 中的光合速率比 CW 提高了 22.7%-24.7%，丙二醛含量降低了 16.6%-29.0%，超氧阴离子产生速率降低了 14.9%-22.7%，HO 含量降低了 10.7%-27.1%。与 CW 相比，CM 中 PSⅡ光化学能量的量子产率增加了 15.8%，调节非光化学能量损失的量子产率增加了 7.2%，非调节非光化学能量损失的量子产率降低了 24.7%，并且 AsA-GSH 循环中的关键代谢酶的活性也在不同程度上提高。我们得出结论，外源褪黑素的应用可以通过平衡 PSⅡ吸收能量的分配和增强叶绿体中 AsA-GSH 循环的 ROS 清除效率来缓解番茄幼苗在低温胁迫下的光抑制。
