Effects of drought stress and rehydration on the morphology and physio-logical characteristics of betel nut seedlings
In this study,changes in morphological and physiological characteristics of betel nut seedlings during drought stress and rehydration were investigated by using potting water control method to evaluate the effects of drought stress and rehydration on betel nut seedlings.Normal watering was used as the control(CK)and the drought time was set to 5 d,10 d,15 d,20 d,25 d,and 30 d.Rewatering was performed immediately after sampling at each drought time node,and sam-pling was performed on 1 d,4 d,and 7 d after rewatering,respectively.The results showed that the root-crown ratio of betel nut seedlings increased after drought.After rewater-ing,the root-crown ratio did not return to the CK level ex-cept for the 5 d drought treatment.The water content of roots,stems,leaves and seed kernels,net photosynthetic rate(A),transpiration rate(E),intercellular CO2 concen-tration(Ci)and stomatal conductance(Gs)showed de-creasing trends with the extension of drought time.The water content of roots,stems,leaves and seed kernels,as well as A,E,Ci and Gs reached the minimum at 30 d of drought stress,decreasing by 21.87%,28.97%,75.01%,34.24%,100.00%,92.64%,75.05%and 95.70%,respectively,compared with CK.The water content of roots,stems,leaves and seed kernels,and A,E,Ci and Gs all recovered significantly after rewatering before 20 days of drought,but the recovery effect was not ob-vious at 25 days of drought.Peroxidase(POD)activity showed a trend of increasing first,then decreasing and then increas-ing,while catalase(CAT)activity,superoxide dismutase(SOD)activity and malondialdehyde(MDA)content increased first and then decreased with the extension of drought time.The activity of SOD reached the maximum at 10 d of drought,in-creasing by 9.48%compared with that in CK.The activities of CAT and POD reached the maximun at 15 d of drought,in-creasing by 317.99%and 44.88%,respectively,compared with CK.The content of MDA reached the highest at 25 d of drought,which increased by 59.99%compared with CK.In summary,the longest drought time for betel nut seedlings to main-tain normal growth was 20 days.When the continuous drought exceeded 20 days,it would cause irreversible damage to betel nut seedlings.Therefore,betel nut seedlings must be irrigated within 20 days of continuous drought.
万方数据
维普
