Abstract: Two pepper(Capsicum annuum L.) lines with different fruit firmness were selected and their fruit firmness was measured during the fruit ripening.Meanwhile,the characters related to the fruit firmness such as contents of primary pectin,soluble pectin,and cellulose were monitored,and the cell wall hydrolases such as Pectin Methyl-esterase(PME),Polygalacturonase(PG),β-Galactosidase,and Cellulase were also analyzed during ripening.The results showed that the maximal fruit firmness of both lines was at stage Ⅲ(color turning),then the fruit firmness decreased during ripening,concomitant with the increase of soluble pectin content.The cellulose content of Line 529 decreased after stage Ⅰ(premature fruit stage),but Line 585 changed a little.The PME activity of Line 529 was developed from stage Ⅰand was maximal at stage Ⅲ,but the maximal PME activity of Line 585 was at green mature stage.The activity of PG increased continuously and was maximal at stage Ⅳ(red mature).The activity of cellulase was increasing during fruit ripening and maximal at stage Ⅲ.The β-Galactosidasethe activity of two pepper lines reached the maximal value at the stage Ⅳ.These results suggest that the changes of fruit firmness was closely correlated with the contents of soluble pectin and the cellulose,which was further related to the PG,PME,β-Galactosidase and Cellulase activities during fruit ripening.These related characters can reflect the firmness type of pepper fruit and provide information for the pepper breeding of storage and transportation tolerance.

Key words: Pepper, Fruit firmness, Pectin, Cellulose, Cell wall hydrolases

CLC Number: 

• S641.3