Study on drought resistance characteristics of'Xianglin 210'Camellia oleifera
[Objective]This study aimed to investigate the changes in photosynthetic characteristics and related physiological indicators of the current main varieties of Camellia oleifera'Xianglin 210'seedlings under drought stress,and provide data support for subsequent drought-resistant breeding and drought-resistant gene mechanisms of C.oleifera.[Method]Five-year-old C.oleifera seedlings of'Xianglin 210'were used as experimental materials,and the same-age seedlings of local regional improved variety'Hengdong 2'were used as control.Pot water control was used to simulate drought stress test.The normal water supply control group(CK,75%-85%of soil maximum water holding capacity)was set up,and the drought gradient was set up.Mild drought(T1,55%-60%of soil maximum water holding capacity),moderate drought(T2,40%-45%of soil maximum water holding capacity)and severe drought(T3,30%-35%of soil maximum water holding capacity).Photosynthetic fluorescence parameters were measured at each gradient and leaves were collected for physical and chemical index detection.[Result]1)With the deepening of drought,there were significant differences in the parameters of C.oleifera seedlings.The minimum initial fluorescence Fo showed a significant upward trend,while the net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),transpiration rate(Tr),and maximum photochemical efficiency(Fv/Fm)showed a significant downward trend,some of which showed extremely significant differences,and the magnitude of the decrease was more significant with the deepening of drought.2)With the deepening of drought,the contents of reduced glutathione(GSH),malondialdehyde(MDA),proline(Pro),and the activity of phenylalanine ammonia-lyase(PAL)in leaves showed a significant upward trend,while superoxide dismutase(SOD)activity showed an initial increase and then a decrease,but the overall trend of SOD was upward.3)Correlation analysis,principal component analysis,and membership function analysis of the 10 indicators showed that there was a significant correlation between the drought resistance of C.oleifera and 10 indicators,some of which were extremely significant.[Conclusion]C.oleifera has certain drought resistance,and there are differences in drought resistance between varieties under drought stress.The drought resistance of'Xianglin 210'is stronger than that of'Hengdong 2'.Therefore,'Xianglin 210'has stronger vitality under continuous drought conditions.
Camellia oleiferadrought stressphotosynthetic fluorescence characteristicsphysiological index
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