叶片水分亏缺对猕猴桃细菌性溃疡病抗性的影响OA

To clarify the correlation mechanism between moisture conditions and Pseudomonas syringae pv.actinidiae(Psa)infection in kiwifruit,this study used the highly susceptible cultivar'Hongyang'under two relative humidity treatments:60％±2％(water deficit group)and 90％±2％(high humidity group).Colony counting,fluorescence observation,and scanning electron microscopy were employed to investigate the effects and mechanisms of moderate water deficit treatment on bacterial canker.The results were as follows:(1)Plants under early water deficit treatment exhibited higher initial enzyme activities of catalase(CAT),superoxide dismutase(SOD),glutathione reductase(GR)and phenylalanine ammonia-lyase(PAL),lower stomatal aperture,and had only about 1/5 of the pathogen load in leaves compared to the high humidity group after 12 days inoculation.(2)When infected plants from the high humidity group were transferred to water deficit conditions,leaf fluorescence showed diffuse patterns after 7 days,and pathogen mortality reached 99.38％after 12 days of treatment;this treatment effectively induced a decrease in leaf water potential,stomatal closure,and significantly enhanced antioxidant enzyme activities.In conclusion,water deficit reduces pathogen invasion by decreasing leaf water potential and promoting stomatal closure,while enhancing plant resistance through antioxidant enzyme regulation,not only inhibiting Psa infection and proliferation,but also eliminating established pathogens.This study confirms that moderate water deficit effectively controls kiwifruit bacterial canker,enriches the"water-plant-pathogen"interaction framework.It provides new ideas and theoretical references for the prevention and control of bacterial canker in kiwifruit,and also lays a theoretical foundation for the popularization of field water management strategies such as rain-sheltered cultivation.