Effects Of 1-Methylcyclopropene On Senescence And Quality Maintenance In Leafy Vegetables

Four leafy vegetables planted in Nanjing were treated with 1-MCP to investigate the effects of 1-MCP on postharvest physiology, quality and activated oxgen metabolism during storage.The following is the result.1. The effects of 1-methylcyclopropene (MCP) at concentrations of (0-2μl/L) on physicological changes and shelf life in Garland chrysanthemum used at 20℃were investigated. The results indicated that treatments with high concentrations (higher than 0.5μl/L) of 1-MCP maintained lower levels of respiration rate, weight loss, accumulation of amino acid and membance permeability and retarded protein degradation in the leaves. The shelf life was significantly extended. In contrast, treatment with low concentration (0.05μl/L) may have no siginificantlly effect on the shelf life.2. Shelf life of Shepherd's purse and India Horseorchid were prolonged by treatment with higher concentrations(up to 5μl/L). Chlorophyll, protein content, Vc degradation were retarded and accumulation of amino acids, Ion leakage were ihibited by 0.5μl/L 1-MCP in the Shepherd's purse and India Horseorchid. 0.5μl/L 1-MCP improved the respiration rate during 2 days and inhibited the ethylene production in Shepherd's purse,however, had no effect on respiration rate and delayed the ethylene peak in the India Horseorchid.3. Treatment with 100ppm ethephon increased the senescence of California Burclover. While 0.5μl/L 1-MCP significantly inhibited the senescence process of harvested California Burclover, as manifested in lower of MDA content, ion leakage and respiration rate and higher levels of H value, chlorophyll and protein content. Treatment with ethephon together with 1-MCP, however, lead to H value, chlorophyll higher than those in control leaves. Accumulation of amino acids and MDA content treated with ethephon together with 1-MCP were lower than that in controls.These suggest that exogenous ethylene-induced the senescence of California Burclover was delayed by 0.5μl/L 1-MCP.4. 0.5μl/L 1-MCP treatment reduced the decreased in H value, chlorophyll and activity of chlase and the increased in MDA and H₂O₂ content and maintained lower levels of membance permeability and the blance of activated oxgen metabolism. 100ppm ethephon, however, increased decline in degration of chlorophyll and decline in H value and increased the activity of chlase, resulted in the imbalance of activated oxgen metabolism, therefore enhanced the senescence of California Burclover.