Research Of Different Varieties Grapes SO₂Injury Threshold And SO₂Injury Mechanism Of Red Grape

Red globe grape from the Xinjiang Uygur Autonomous Region and Augusta、Victoria、 Rizamat grape from Tianjin were fumigated with sulfur dioxide to ascertain acute and chronic injury threshold value of sulfur dioxide to grapes, to study the best methods and concentration of SO2fumigation and to study the change of physiochemical and micro structural characteristics in relation to sulfur dioxide. Providing theory for avoiding grape’s injury during produced progress.(1) under the same processing, different regions of different varieties of grapes has different SO2chronic injury time under the low temperature, SO2acute damage threshold and chronic injury threshold were different under low temperature and room temperature, the red grape appeared injury after stored40days, auguste grapes appeared injury after stored45days, Victoria grape appear damage time was48days, and force into rizamat grape storage under low temperature60days didn’t appear SO2injury. The same grape under room temperature were more sensitivity to SO2than grape under low temperature, the four kinds of grapes sensitivity to SO2from high to low was:Red grape, Auguste, Victoria and Rizamat grape.(2) By studied the dynamic of SO2absorption of Red grape and Victoria grape under low temperature, it was concluded that during the storage of fumigation, grape stem SO2residue growth in a linear trend, SO2absorption accumulation rate was highest, followed by fruit brush, and the grape spell and pulp in SO2accumulated relatively slowly, therefore deduced that SO2mainly through stem brush into the fruit and fruit, fruit stalk and fruit brush were especially vulnerable to the SO2bleaching damage.(3) Determined the best concentration of SO2fumigation and fumigation methods for four varieties of grape:Red grape was that the first time fumigation2000μl/L×1.0h, every15days,500μl/L×0.5h fumigation processing; Auguste grape was that fumigation2000μl/L×1.0h for the first time, every15days,500μl/L×0.5h fumigation processing; Victoria grape was that first3000μl/L×1.0h fumigation, every15day,1000μl/L×0.5h fumigation processing; Force Rizamat grape was that3500μl/L×1.0h, every15days,1000μl/L×0.5h fumigation processing.(4) By studying SO2injury mechanism of red grape under the low temperature storage, it was concluded that SO2injury has significant effects on grape physiological metabolism and physiological quality, could restrain the changes of respiration intensity, promoted decomposition of stem chlorophyll and spell anthocyanin, inhibited vitamin C and pulp acidity decrease; Destroyed the integrity of the cell membrane, increased the electrical conductivity and malondialdehyde content; Stimulated polyphenol oxidase and peroxidase activity, enhanced the enzyme activity. Damaged to the skin surface wax layer and skin cells, caused the skin surface bleaching injury.