Research On The Effects Of Drought Stress On Ziziphus Jujuba Var.Spinosa Seedlings

This paper took annual Ziziphus jujuba var.spinosa seedlings as research material,used water-control of potted plant,set four moisture grad-ient as 80%(CK),60%(LD),40%(MD)and 20%(SD)of field capacity,and studied growth index,physiological and biochemical index,photosyntheti c characteristics and change of leaf anatomical structure of Ziziphus jujuba var.spinosa seedlings under the drought stress to reveal the respo nse and adaptation rules of Ziziphus jujuba var.spinosa seedlings on dro-ught gradient and results showed that:(1)Under mild stress,H,D and biomass of Ziziphus jujuba var.Spinosa seedling had promotion relatively.With the degree of drought stress intensified,H,D and biomass of Ziziphus jujuba var.spinosa were signifiacantly lower than CK,and the root-shoot ratio increased with the degree of drought stress intensified.The sour dates can be adapted to the soil’s water shortage by changing the ground and underground parts.(2)With the stress level increased and stress time extended,leaf relative water content gradually reduced,membrane lipid peroxidation en-hanced,MDA content increased gradually,Pro content accumulation increased gradually,and antioxidant enzymes(SOD,POD,CAT)activity showed change tendency of first rise and then fall.Ziziphus jujuba var.spinosa maintained their normal growth through a series of physiological and biochemical reaction.(3)Photosynthetic pigment chlorophyll a,chlorophyll b,chlorophyll(a+b),carotenoid content,net photosynthetic rate,transpiration rate and stomatal conductance reduced with the stress level increased and stress time extended while intercellular CO2 concentration first rise then fall.(4)Leaf thickness,palisade tissue thickness and sponge tissue thick-ness changed thinning gradually,mesophyll structure tightness(CTR)and mesophyll structure looseness(SR)became close as the degree of stress strengthening,The fence is getting bigger.Ziziphus jujuba var.spinosa can change its structure to suit the ability of drought stress.(5)Little stress is beneficial to the growth of Ziziphus jujuba var.spinosa,Ziziphus jujuba var.spinosa seedlings comprehensive force of the critical value of 53.8%.