| In this paper, the postharvest storage of Red Globe grape was studied. The grapes were intermittently fumigated for 2 h per 10 days with 0 ?L/L?50 ?L/L, 100 ?L/L, 250 ?L/L, 500 ?L/L, 1000 ?L/L SO2 at0?,RH 95%. The influence of SO2 intermittent fumigation on physiological and biochemical quality changes, the sensory quality, active oxygen metabolism and organization structure of the grape were studied.The effects of intermittent fumigation on the anthocyanin synthetase and its related genes were also studied. This research tried to find out the possible reasons of the postharvest quality change caused by SO2 intermittent fumigation, so as to provide theoretical basis of new method and thought to rationally use SO2 and prevent the SO2 damage to grape.(1)The Red Globe grapes were fumigated for 2 h(every 10 days)with 0 ?L/L?50 ?L/L?100 ?L/L?250 ?L/L?500 ?L/L?1000 ?L/L SO2 and stored at low temperature( 0?, RH 95%). The grapes without any treatment were taken as contrast. The firmness, SSC, chlorophyll content of stalk, TA, cell membrane permeability, decay rate, bleaching index and SO2 residue of grapes were determined. Results showed that the 100 ?L/L SO2 can significantly reduce the decay rate while the SO2 residue did not exceed the national standard. This 100 ?L/L SO2 treatment can also inhibit the increase of cell membrane permeability and the bleaching index, maintain the firmness, SSC, chlorophyll content of stalk and TA effectively. So the storage period of the Red Globe grape was prolonged.(2)The TPA was used to study the grape change of firmness, cohesiveness, elasticity, viscosity and chewiness during the storage. With the extension of storage period,the firmness, cohesiveness, elasticity,viscosity and chewiness decreased, but the 100 ?L/L SO2 treatment can significantly inhibit the change and there was a remarkable difference in 500 ?L/L SO2 treatment except plastic viscosity. It was showed that100 ?L/L SO2 treatment could maintain the sensory quality of grape effectively.(3)100 ?L/L SO2 treatment delayed the decline of CAT and APX activity, promoted the increase of POD and SOD activity, restrained the production rate of O2·-and content of H2O2 and suppressed the PPO activity.It was suggested 100 ?L/L SO2 treatment could delay the senescence and browning of the Red Globe grapes.(4) The changes of stalk surface and skin structure of the grapes were observed by SEM. At the beginning of postharvest storage, the stalk stoma structure and wax layer structure of skin were integrity both in the 100 ?L/L?500 ?L/L SO2 treatment and contrast grapes. With the extension of storage time, the opening rate of stoma was reduced in 500 ?L/L SO2 treatment group and the damaged was happened in contrast group. The integrity of the wax layer was destroyed in 500 ?L/L SO2 treatment group while hollow disease spotswith ring-shaped shadow appeared in the surface of contrast grapes.The results showed that SO2 treatment was an accumulated process on the damage of the fruit and it might exist a certain stress response of grapes to prevent damage.(5) 100 ?L/L?500 ?L/L SO2 treatment can inhibit anthocyanins enzyme's activity but it would cause the decline of total anthocyanins amount in grape skin during storage. 100 ?L/L SO2 can promote PAL and4 CL activity during the approach of anthocyan in synthesis, induce the up-regulated expession of 4CL and PAL gene, and enhance the transformation of PHE. 100 ?L/L SO2 treatment enhanced LDOX gene up-regulated expression,and it would make the grape skin bleaching by inhibiting the DFR gene expression. |
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