Effect of SO₂ fumigation on cell ultrastructure and the content of anthocyanins of red globe grape

Objective:The effects of SO₂ fumigation on cell ultrastructure, anthocyanin degradation and related gene expression of the red globe grape were studied. Methods:The red globe grape was fumigated by 100 and 500μL/L SO₂.The surface structure of the stem was observed by scanning electron microscope (SEM). The content of anthocyanin and the activity of anthocyaninase, PAL, 4CL in peel were detected by ulfraviolet spectrophotometry. The expression level of anthocyanin synthase-related genes were determined byreal-time quantitative PCR. Results:100μL/L SO₂ fumigation treatment on the red globe grape inhibited the stem of grape stomatal, the activity of anthocyanin in peel and the increasing of PAL, 4CL activity. The expression of PAL, 4CL and LDOX genes was up-regulated, but the DFR gene was down-regulated by SO₂.Conclusion:The lower concentration of SO₂ would through increase the anthocyanin synthesis of enzyme activity and gene expression to control the content of anthocyanins. Thus delayed the decline of the content of anthocyanins and the reduce fade symptoms of the peel.