Study On The Regulation Mechanism Of Nitric Oxide In Tomato Fruit Maturation

In this study, the effects of postharvest treatment with NO on contents of soluble sugar and starch as well as the activities of ACC svnthase and ACC oxidase in tomato at room temperature were studied. And the in vivo or in vitro effects of NO on polygalacturonase mRNA. protein, enzyme activities with NO were also investigated. The relationships between nitric oxide and ripening of tomato were discussed. The results are as follows:I. The degradation of the polysaccharide and the generation of soluble sugar, especially the generation of fructose, were inhibited by short time treated with NO. simultaneously the transformation of soluble sugar to starch was promoted. The transformation of starch to soluble sugar was promoted when prolong the treatment time.II. NO could reduce the rate of ethylene production by inhibiting the activities of ACS and ACO. The activities of ACS and the ethylene production were enhanced when prolong the treatment time.III. It could increase the enzyme activity of polygalacturonase treated with NO in vivo. The transcription of mRNA regulated by ethylene ,so the content mRNA was fewer in the sample treated with NO than Control.IV. Purified protein of PG was isolated from tomatoes and the antibody of PG was prepared. .Results of Western Bloting shown that there was no obviously changes at protein level after the treatment with NO.V. The in vitro effect on PG activity by the treatment with SNP of 100μM was most significant, and the change can be recoverd by DTT and GSH. Such results suggest that the post-translational modification may occur during the treatment with NO.