Effects Of Exogenous Spermidine On Physiological And Ecological Of Two Different Varieties Of Camellia Oleifera Abel.under Waterlogging Stress

Waterlogging caused by extreme rainfall and typhoons have not only restricted the cultivation of Camellia oleifera Abel.but also directly affect the growth and yield of C.oleifera.Spermidine(C₇H₂₂N₃,Spd),as a bioactive substance to improve plants’resistance to environmental stress,is an important physiological and metabolic regulator in plants’regulation of their own growth and development.The purpose of this study was to reveal the effects of exogenous spermidine on the physiological,biochemical and resistance of different varieties of C.oleifera under waterlogging stress.To evaluate the effect of exogenous spermidine on improving the water resistance of two different varieties of C.oleifera.In this study,Camellia oleifera“Hailin 1”and Camellia oleifera“Hailin 2”were used as experimental materials to investigate the effects of exogenous imino on the growth,photosynthesis and physiological and biochemical characteristics of two varieties of C.oleifera seedlings under waterlogging stress（Half waterlogging,40 days）.The results showed that:（1）In the pre-test of exogenous spermatine solubility screening,the membership function values of each treatment group at room temperature were ordered as follows:0.5mmol/L>0.1 mmol/L>1 mmol/L.This indicated that the spermidine concentration with the best effect of easing waterlogging inhibition was 0.5 mmol/L.（2）Under waterlogging stress,Growth index（plant height,ground diameter,root activity）,photosynthetic index（net photosynthetic rate（Pn）,stomatal conductance（Gs）,intercellular carbon dioxide（Ci）,transpiration rate（Tr）,water utilization ratio（WUE））,photosynthetic pigment（chlorophyll a（Chl a）,chlorophyll b（Chl b））,total chlorophyll（TChl）,carotenoid（Caro）),leaf water potential,the cell membrane system(conductivity（RC）,malondialdehyde（MDA）,hydroxyl radical（·OH）and hydrogen peroxide（H2O2）,osmoregulation substances（proline（Pro）,soluble sugar（SS）and soluble protein（SP））and antioxidant enzyme system(superoxide dismutase（SOD）,peroxidase（POD）,catalase（CAT）,alternative oxidase（AOX）and glutathione peroxidase（GSH-Px）and so on have been significantly negative impact;（3）Spraying exogenous and spermine under water stress could significantly improve the two different varieties of camellia plant height,diameter growth,Pn,Gs,Ci,Tr,WUE,photosynthetic pigment chlorophyll a and chlorophyll b,TChl and Caro content,leaf water potential,reduce the RC,MDA,·OH and H₂O₂ content of free radicals,increase the accumulation of osmotic regulation substances Pro,SS and SP,increased the SOD,POD,AOX and gsh-px activity of antioxidant enzymes and so on.The results showed that the two varieties of C.oleifera were sensitive to waterlogging stress,and spraying spermine could enhance the waterlogging tolerance of C.oleifera in a short time,thus maintaining and promoting the growth and development of the two varieties of C.oleifera.The results can be used to guide the production and cultivation of C.oleifera under extreme climatic conditions.