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Journal of Tea Science ›› 2022, Vol. 42 ›› Issue (2): 187-199.doi: 10.13305/j.cnki.jts.2022.02.010

• Research Paper • Previous Articles     Next Articles

Effects of Exogenous 5-ALA on the Chlorophyll Synthesis and Fluorescence Characteristics and Gene Expression of Key Enzymes in Tea Plants under Drought Stress

YANG Ni1, LI Yimin1, Li Jingwen1, TENG Ruimin1, CHEN Yi1, WANG Yahui2, ZHUANG Jing1,*   

  1. 1. Ministry of Agriculture Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Tea Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China;
    2. State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2021-11-11 Revised:2021-12-23 Online:2022-04-15 Published:2022-04-15

Abstract: In order to study the regulation mechanism of exogenous 5-aminolevulinic acid (5-ALA) on the chlorophyll synthesis and fluorescence characteristics of tea plants in response to drought stress, tea cultivar 'Shuchazao' was used as the experimental material in this study. Under PEG-6000 simulated drought stress environment and 5-ALA spraying pretreatment, the contents of chlorophyll a, chlorophyll b and total chlorophyll in tea seedling leaves were detected, and the chlorophyll fluorescence parameters and the expressions of key enzyme genes in tea leaves were further determined. The results show that exogenous 5-ALA significantly increased the contents of chlorophyll a, chlorophyll b and total chlorophyll in tea leaves under drought stress. Exogenous 5-ALA alleviated the decreases of maximum fluorescence (Fm), actual photochemical efficiency of PSⅡ [Y()], maximum photochemical quantum yield of PSⅡ (Fv/Fm), photochemical quenching coefficient (qP), potential activity of PSⅡ(Fv/Fo), photosynthetic electron transfer rate (ETR) of PSⅡ reaction center, and the increases of initial fluorescence (Fo) and nonphotochemical quenching coefficient (qN). At the same time, exogenous 5-ALA induced the expressions of chlorophyll synthesis (CsHEMA1, CsHEME1, CsLIN2) and carbon assimilation-related enzymes (CsSBPase, CsTK) in tea plant under drought stress. The study demonstrates that spraying exogenous 5-ALA can effectively alleviate the degradation of chlorophyll and damage to PSⅡ reaction center of tea leaves under drought stress, maintain the higher photosynthetic activity, and improve the photoprotection ability of tea leaves.

Key words: tea plant, 5-aminolevulinic acid, drought stress, chlorophyll fluorescence parameters, gene expression

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