Effects Of Nitric Oxide (NO) On Active Oxygen Metabolism Of Postharvest Tomato

In this thesis, the effects of postharvest treatment with NO on respiration rate, the rate ofethylene production , fruit firmness , membrance permeability, active oxygen metabolism andthe enzyme activities correlated with active oxygen metabolism, and the qualities of 'Baili'tomato fruit during ripening and senescence at ambient temperature 30 ± 2 ℃ wereinvestigated. The relationship of nitric oxide and tomato senescence ,the physiological andbiochemical mechanism of ripening and senescence of tomato were also discussed. All abovewere expected to provide theoretical bases for NO applying to fruit storage. The results of study showed that 'Baili'tomato was climacteric fruit, and had significantpeaks of respiration and ethylene production. NO could reduce the rates of respiration andethylene production, and remarkably degrade the height of ethylene and respiration peaks. Itpostphoned the appearing time of respiration and ethylene peaks. It also delayed the loss offirmness and changes of fruit colour, decreased MDA content and membrance permeability,retarded the decrease of the contents of protein,Vc and change of titratable acidity, inhibitedpartly the increase the contents of H2O2,O2 and increased the enzyme activities relating to .—active oxygen metabolism(SOD,POD,CAT,ASA-POD). NO restained the loss of firmness the increase of respiration rate and ethyleneproduction , postphoned the appearing time of respiration and ethylene peaks, prevented theincrease of active oxygen (H2O2,O2 ), inhibited the decrease of chlorophyll content, .—antioxidant content and the enzyme activities relating to active oxygen metabolism in certaindegree , and retarded the change of fruit colour induced by exogenous ethylene.