The Physiological And Biochemical Effects On Paeonia Ostii Under Waterlogging Stress And Restoration

Paeonia ostii has important ornamental medicinal and oil value.The oil tree peonis have been greatly popularized in the temperate aeras rather than rainy aeras in the China.Among tree peony species,the P.ostii is the best one for waterlogging tolerance,and it also is the most popular oil-utilized tree peony speices.In this study,The potted biennial P.ostii seedlings were cultivated in the artificial chambers,and after one month the seedlings were treated by three conditions,waterlogging stress(waterlogging group),normal conditions(control group)and waterlogging recovery(waterlogging recovery group).During the experimental treatements,the morphology change,physiology and biochemistry affects of treated seedlings were measured by the following indexes,including root morphology,relative water content,relative electric conductivity,antioxidant protection enzymes,osmoregulation substances content and so on.The waterlogging group(and the control group)had 7 sampling points(0h,3h,6h,24h,3d,5d,7d),and the waterlogging recovery group(and the control group)had 3 sampling points(3d+3h,3d+6h,3d+24h).The results are as the followings.First,the obvious changes that the number of absorbing roots reduced and the roots colour getting dark were observed.The number of new lateral roots increased,but the total number of roots was reduced in the process of waterlogging treatment.In addition,the volume of root apical cells increased.After waterlogging recovery,the number and colour of roots,and the volume of roots apical cells returned to the normal leve.Phenotypical changes are not obvious in the beginning of waterlogging treatment,but leaves became curly and dry after treatment of waterlogging for 5 days.Second,the soluble protein content of leaves reduced gradually,but the content of soluble sugar,pro line and methane dicarboxylic aldehyde(MDA)increased in the process of waterlogging treatment.And the content of the main osmoregrulation substance was gradully reduced and almost recovered to normal level after waterlogging recovery.However,the content of soluble sugar reduced not obviously after waterlogging recovery.Third,the activities of many kinds of enzymes,including alcohol dehydrogenase(ADH),superoxide dismutase(SOD),catalase(CAT),pyruvate decarboxylase(PDC)and peroxidase(POD)showed a trend of increasing in the process of waterlogging treatment.And these enzymes were gradually recovered after waterlogging recovery.The activities of PDC and POD recovered to the level of control groups within waterlogging recovery treatment for 24 h.Correlation analysis showed that the activities of the four enzymes except SOD were significant positive correlation with each other.