Studies On The Effects Of Chlorogenic Acid On Fruit Ripening And Senescence In Apples

The chlorogenic acid (CA) played a crucial regulating role in the physiological metabolism in plants. Fruit Ripening and senescence influenced the quality and storage life. In order to understand the mechanism of fruit development, the physiological and biochemical effects of CA were studied on fruit ripening and senescence in apples, so as to provide a new theoretical basis for ripening and senescence control, high quality and storage life. Two cultivars, "Starkrimson" and "Fuji" were used to examine the regulating effects of CA on several enzymes, membrane permeability, ethylene production, respiration rate, quality and storage life. Moreover, the changes of CA content were studied during fruit ripening and senescence.The main results were as follows:1. The total level of CA content was reduced during fruit ripening and senescence. The CA content with "Fuji" was significantly higher than that with "Starkrimson". Different CA content were found in different parts of the two cultivars fruit, being higher seed and core and lower flesh and peel.2. CA at 0.005⁵mmol-L-1' on "Starkrimson" and "Fuji" resulted in the increase of endogenous CA content ,but endogenous CA content increase correlative with CA spraying concentration was not observed.3. Treatment 0.05-0.5 mmol-L-1 CA on "Starkrimson" and "Fuji" apple fruits decreased LOX, PG and IOD activity, decreased the content of MDA and O₂ ,increasedSOD activity and POD activity, which indicated that CA act as protective function to membrane.4. CA at 0.5 rnmol-L-1 could inhibit the respiratory rate in fruits of "Starkrimson" during storage with different treatments, including spraying, injecting and immersing. Exogenous CA could inhibit ethylene biosynthesis after harvest. CA at 0.5 mmol-L-1 was the proper concentration to "Starkrimson" deceased by 45.69% than control at harvest, and the same effect was found one week after harvest. However, CA at 0.05 mmol-L-1 wasthe appropriate concentration to "Fuji" apple deceased by 43.16% than control at harvest, and significant effects were found with treatment O.OSmmol-L-1 CA and 0.005 mmol-L-1 CA one week after harvest.5. Exogenous CA influenced the fruit quality and storage life of apples. Application of CA was found that increase fruit firmness, titable acid content and chlorophyll content. CA spraying on trees, injecting and immersing treatment after harvest could delay apple fruits softening and weight loss.6. CA at O.OO5-5mmol-L-1 influenced PAL activity of "Starkrimson" and "Fuji" apple fruits, indicating that CA regulate phenylalanine catabolism and quality.