Whereas the physiology of fruit ripening of papaya involves from the production of photoassimilates for their training and development to the enzymes that degrade the cell wall promoting pulp softening, the objective of this study was to evaluate the chlorophyll a (Chl a) fluorescence induction kinetics in of papaya (Carica papaya L.) cv. Golden leaves during the reproductive period and to evaluate the total soluble solids (SS), acidity total titratable (ATT), and activity of pectin methyl esterase (PME) during fruit ontogeny. The highest rates of photochemical performance index (PI total) were observed in the stages of fruit formation and growth , due to better performance of the redox reactions of photosystem I [δR0 / (1-δR0)]. Higher photochemical efficiency of plants in this period allows greater demand for fixed carbon for the synthesis of compounds for cellular metabolism. Generally, photoassimilates are directed to the closer strong drains, but the seeds have priority, so the SS, AT and PME activity in flesh fruit, remained constant during their development, and any alterations in these characteristics only in the harvest stage. These results confirm that the PME as an enzyme that prepares the substrate for the other pectic enzymes act, providing the demethylated organic acids and the beginning of the degradation of cellular wall polysaccharides even before harvest.
Fluorescence; chlorophyll; PME; soluble solids; acidity
