Effects Of Water Stress On Growth And Physiological Characteristics Of Prunus Persica Cv. ’Juhuatao’ Seedlings

In order to study the effects of water stress on the growth,physiology and leaf anatomy of Prunus persica cv.’Juhuatao’ seedlings,one year old P.persica cv.’Juhuatao’ grafted seedlings were used as experimental materials to carry out water stress experiments with pot water control method simulating drought and pot covering method simulating waterlogging.The physiological status of P.persica cv.’ Juhuatao’seedlings under drought and waterlogging stress was analyzed in order to provide theoretical reference for the expansion of ornamental peach cultivation.The main results are as follows:(1)Under water stress,The seedlings of P.persica cv.’Juhuatao’ survived under drought stress.With the extension of stress time and the enhancement of stress degree,the leaf wilting and curling degree,yellowing area,white spot area and defoliation amount increased gradually.Under mild waterlogging,the morphological difference of seedlings was not obvious;under severe waterlogging,the seedlings began to die from 16 d,and the morphological changes of seedings increased from from 16 d to 30 d,and all the seedlings died at 30 d.(2)Under water stress,ground diameter,seedling height and biomass were inhibited.Under severe drought,the ground diameter and seedling height were 58.59%and 19.78%of the control,respectively;under severe water waterlogging,the ground diameter and seedling height were 41.41%and 19.64%of the control,respectively.Under drought and waterlogging stress,the indexes of seedling roots decreased.(3)The relative water content of leaves of P.persica cv.’Juhuatao’ seedlings decreased with the extension of water stress time and the enhancement of water stress degree.At the end of severe drought and severe waterlogging,the relative water content of drought and waterlogging were 74.52%and 71.22%of the control,respectively.(4)Chlorophyll a,chlorophyll b and carotenoids of P.persica cv.’Juhuatao’seedlings were 80.05%,52.28%and 89.33%of the control under severe drought,and 67.50%,73.49%and 47.84%of the control under severe waterlogging.(5)Under water stress,the MDA content of P.persica cv.’Juhuatao’ seedlings increased gradually with the extension of stress time and the strengthening of stress degree,and the increasing trend was greater in the later stage of stress and under severe stress.(6)Under drought stress,soluble protein content first increased and then decreased,and proline content gradually increased;under water waterlogging stress,soluble protein content first increased and then decreased,and proline content gradually increased.Under water stress,soluble protein content and proline content changed more significantly in the later stage and under severe stress.(7)Under water stress,the activities of pod and SOD increased in the early stage of stress,but decreased in the middle and late stage of stress,and the increase of enzyme activity was less than the decrease.(8)Under water stress,net photosynthetic rate,stomatal conductance and transpiration rate of P.persica cv.’Juhuatao’ seedlings gradually decreased,intercellular CO2 concentration and water use efficiency first increased and then decreased.(9)Under water stress,the main vein thickness,xylem area and vascular bundle area of P.persica cv.’Juhuatao’ seedlings leaves decreased gradually;leaf thickness;,sponge tissue thickness and palisade tissue thickness decreased gradually;stomatal length,stomatal width and stomatal density decreased gradually.In conclusion,the seedlings of P.persica cv.’Juhuatao’ have strong drought resistance and are not tolerant to waterlogging.