Effect of Magnesium Deficiency on the Physiological Characteristics of Red-global Grape Seedling

[Objective] The aim was to supply theoretical foundation for the timely diagnosis of magnesium deficiency symptom of cultivated red-global grape and its balanced fertilization.[Method] The magnesium content was determined by atomic absorption colorimetry.The content of MDA and the activities of SOD and POD were determined with reference to Lihesheng method.[Result] When the magnesium was deficient,the contents of magnesium and chlorophyll and the activities of SOD and POD decreased significantly,the content of MDA increased significantly and the variations of indices began to be significant after 60 d since magnesium deficiency.At this time,the magnesium content in magnesium deficiency treatment decreased by 47.6% in comparison with CK,the chlorophyll content in CK reached its maximum,the contents of MDA in magnesium deficiency and low magnesium treatments and CK began to increase significantly,the activities of SOD reached their maximum in low magnesium treatment and CK and the activities of POD in magnesium deficiency and low magnesium treatments began to decrease.The activity of POD in low magnesium treatment for 120 d decreased by 30.5% in comparison with CK.The chlorophyll contents in magnesium deficiency and low magnesium treatments for 90 d decreased by 65.2% and 67.7% resp.in comparison with CK.[Conclusion] In magnesium deficiency and low magnesium treatments,the variations of indices were mainly centralized in the early growth stage.So,the attention should be attached to applying magnesium fertilizer in the early growth stage of grape.