Effects of Exogenous Melatonin on Photosynthetic Characteristics,Antioxidant System and Yield of Rice under Low Temperature Stress in Different Periods
Xu Lingqi
Du Xiaodong
Cai Yongsheng
Yang Limin
Zhao Haixin
Chen Shuqiang
Han Xiao
Xue Jingfang
Huang Xiaoqun
Abstract：In order to explore the mitigation effect of exogenous melatonin treatment on low temperature stress in rice in different breeding periods,this potted planting experiments was carried out in 2023 by setting three treatments of outdoor normal growth(CK),low temperature stress(LT),and low temperature stress af-ter spraying melatonin(MT),and the effects of low temperature treatment after spraying exogenous melatonin at tillering stage(TS),ear pregnancy stage(BS)and grouting stage(FS)on rice photosynthetic characters,antioxidant system and yield were studied.The results showed that compared with LT treatment,MT treatment significantly improved the dry weight of leaves,stem and sheath in TS and BS periods,and the net photosyn-thetic rate(Pn),stomatal conductivity(Gs)and intercellular CO2 concentration(Ci)of rice leaves in TS,BS and FS periods.Compared with LT treatment,MT treatment significantly increased the activity of superox-ide dismutase(SOD)of rice leaves in the three growth periods by 22.90%to 33.18%,increased the peroxi-dase(POD)activity significantly by 8.47%to 17.38%,and improved the catalase(CAT)activity significant-ly by 5.49%to 13.14%.Compared with LT treatment,MT treatment significantly increased the content of sol-uble sugar,soluble protein and proline in rice leaves in the three growth periods,and the content of malondi-aldehyde(MDA)was significantly reduced by 13.73%,10.66%and 18.71%.The actual output of MT treat-ment during different growth period significantly increased by 17.79%,22.10%and 27.93%respectively com-pared with LT treatment.In conclusion,spraying exogenous melatonin could reduce the oxidative damage of low temperature stress to rice leaves,stabilize the physiological metabolism of rice plants,and ultimately alle-viate the loss of rice yield caused by low temperature stress.
Keywords：RiceMelatoninPhotosynthesis characteristicsAntioxidant systemYield
Publication Date：2025-09-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：8( 64-71 )