Hydrolysing enzymes and respiration during ripening of tomato (Lycopersicon esculentum) fruits

Two varieties of tomato fruits, viz. Pusa Ruby and Pusa Gaurav, were studied with an attempt to get a better understanding of the relationship between respiration rate and hydrolysing enzymes during ripening. Pectin methyl esterase (PME) and polygalacturonase (PG) increased as ripening proceeded and reached a peak on 4th day after harvest followed by a decline. Respiration rate increased along with the activity of PME and PG with cyanide-resistant respiration being increasingly dominant compared to cyanide-sensitive respiration. There seems to be a close relation between the respiration (alternate) and hydrolysing enzymes during ripening of tomato fruit.