甜樱桃对干旱胁迫的生理响应机制及其耐旱性评价OA

[Objective]The present paper investigated the effects of different drought stress intensities on the growth and physiological-bio-chemical indices of three sweet cherry seedlings('Isabella''Kosala'and'Big star'),evaluated their drought resistance and rehydration recovery capacity,and revealed the patterns of osmotic regulation substance accumulation,photosynthetic response and antioxidant enzyme ac-tivity changes,so as to provide a theoretical basis for drought-resistant cultivar selection and water-saving cultivation.[Method]Three sweet cherry cultivars were selected,each with four treatment groups(10 plants/group):control(CK),light drought(LD),moderate drought(MD)and severe drought(SD).After 21 days of drought stress,rehydration was conducted for 14 days.Growth and physiological-biochemi-cal indices were observed every 7 days,and unified determination and analysis were performed at the end of the experiment.[Result]Under drought stress,significant differences in morphology and physiology were observed among the three sweet cherry cultivars.'Isabella'showed the largest decreases in plant height,fresh weight and dry weight,with slow recovery after rehydration;'Kosala'had moderate reductions in these traits and partial recovery post-rehydration;'Big star'had smaller decreases in plant height,fresh weight and dry weight during stress,displayed the best recovery ability after rehydration,and kept its relative water content relatively stable.In terms of photosynthetic parameters,under drought conditions,the Pn,Tr and Gs of'Kosala'and'Isabella'were significantly lower than those of the control group(CK);after rehydration,all three cultivars showed an upward trend in these parameters.After rehydration,the MDA content of the three cultivars gradual-ly decreased,while the SP content increased.Meanwhile,the activities of key antioxidant enzymes such as CAT,SOD and POD showed an o-verall recovery trend,accelerating the restoration of plant antioxidant capacity.[Conclusion]Different sweet cherry cultivars exhibited both commonalities and specificities in stress response.The comprehensive evaluation of drought tolerance by the subordinate function method indi-cated the following order:under LD,it was'Kosala'＞'Isabella'＞'Big star';under MD,it was'Big star'＞'Isabella'＞'Kosala';under SD,it was'Big star'＞'Kosala'＞'Isabella'.Among them,'Big star'showed the strongest drought tolerance under both MD and SD conditions,with prominent drought-resistant characteristics.Principal Component Analysis(PCA)screened out 5 key physiological indi-cators,namely Pn,RW,SP,MDA and Tr,which could provide a theoretical reference for drought tolerance evaluation,cultivar breeding and cultivation management of sweet cherries.