Study On Adaptability Of Two Blueberry Varieties To Water Stress

Blueberry is a small berry tree species with high economic value,its unique edible value and health care value are favored by consumers.The number of new cultivars is increasing,and the cultivation area is expanding from the north to the south.In this study,water stress(drought stress,waterlogging stress)was carry out by pot experimen,and three-year-old cuttings of 'Britewellt'and'Legacy' as experimental.Through discussion the effects of water stress on the morphological structure,physiological characteristics,photosynthesis and chlorophyll fluorescence parameters of blueberry to synthetically evaluate its drought resistance and waterlogging resistance and provide a theoretical reference for the industrialization of blueberry under different cultivation conditions in South China.The main results are as follows:(1)With the increase of water stress,the gro,wth of leaves of Britewellt and Legacy were inhibited,leaf length,width and specific leaf weight gradually decreased,and defoliation occurred.Legacy was more injured by water stress,and the rate of defoliation was up to 70%.(2)With the increase of water stress,the development of leaf structure of Britewellt and Legacy were limited to some extent,and anatomical structure of Legacy leaves was more susceptible to water stress.The maximum decreases of leaf thickness,palisade tissue thickness and spongy tissue thickness were 28.80%,31.53%and 30.58%.(3)With the increase of water stress,the stomatal length,width and opening of Britewellt and Legacy decreased gradually,stomatal density increased gradually under drought stress,but increased first and then decreased under waterlogging stress,the stomatal regulation function of Legacy was more restricted.(4)With the increase of water stress,the relative conductivity and MDA content of Britewellt and Legacy increased gradually,and the permeability of cell membrane increased.The membrane system of Legacy is more affected,the highest relative conductivity and MDA content were 4.02 and 2.05 times of the control.(5)The contents of proline and soluble sugar in the leaves of Britewellt and Legacy increased under water stress.Britewellt accumulated more osmotic regulators,the highest content of proline was 2.40 times higher than that of the control,while the soluble sugar was 3.02 times higher.(6)SOD and POD activities of antioxidant enzymes in leaves of Britewellt and Legacy increased under water stress.Britewellt leaves maintained higher activity of antioxidant enzymes under water stress,the maximum was 2.68 times and 3.84 times of the control.(7)With the increase of water stress,the content of photosynthetic pigments,Pn,Gs and Tr of Britewellt and Legacy decreased gradually,Ci decreased first and then increased under drought stress,while increased continuously under waterlogging stress.The photosynthesis of Legacy was more affected.(8)With the increase of water stress,the minimum fluorescence(F0)of Britewellt and Legacy increased gradually,while the maximum fluorescence(Fm),the Photochemical efficiency of PSII(Fv/Fm)and the Photochemical efficiency of PSII(Fv/F0)decreased gradually,the PSII photoreaction center of blueberry was damaged to some extent,and Legacy was more affected.(9)The comprehensive evaluation results show that:the effect of waterlogging stress on the growth of blueberry was greater than that of drought stress.The drought resistance and waterlogging resistance of Britewellt were stronger than that of Legacy.