Abstract: ‘Rizamat’grape berries were treated with 50，100 and 200 mg ? L-1 NAA separately at veraison. The results showed that the accumulation of glucose，fructose，sucrose and soluble sugar was significantly inhibited，and the degradation of tartaric acid，malic acid，citric acid，oxalic acid and total acid was also hindered by the treatment of NAA. Comparing three different treatments，the effect of NAA with 200 mg ? L-1 was the most remarkable，but sugar and acid compositions were not changed. The expression of SS and SPS，which were the soluble sugar-metabolism related genes，was also inhibited by the treatment of NAA. But the expression of NI was inhibited in prometaphase and promoted at later stage. The expression of FRK was contrary to the NI. For organic acid related genes，the expression of MDH and PEPC was promoted by the treatment of NAA，and the expression of ME was inhibited. But the effect on the expression of IDH was not significant. Therefore，we speculate that the reason for delaying fruitripening of exogenous NAA is that parts of the sucrose and acid-metabolism related genes expression are changed，and then the accumulation of sugar and degradation of acid are hindered.

Key words: grape, naphthylacetic acid, soluble sugar, organic acid, gene expression