Regulation of detached coriander leaf senescence by 1-methylcyclopropene and ethylene

Senescence of detached coriander was significantly inhibited by treatments with 50 nl 1(-1) or higher concentrations of 1-methylcyclopropene (1-MCP). During the 8 days of storage at 20 degreesC, chlorophyll and protein degradation in the leaves was significantly retarded by 100 nl l(-1) 1-MCP, and promoted by 10 mul l(-1) ethylene. Treatment with 1-MCP together with ethylene, however, led to protein levels considerably higher than those measured following ethylene treatment and even higher than those in control leaves. 1-MCP decreased and ethylene increased accumulation of amino acids. Treatment with 1-MCP together with ethylene remarkably reduced accumulation of amino acids. to levels lower than those in control leaves. The respiration rate in leaves treated with 1-MCP was substantially higher than that in controls during the last 4 days. Ethylene production by leaves was significantly enhanced by treatment with 1-MCP. The effects of 1-MCP in retarding and of ethylene in enhancing senescence were reduced at low temperatures (10 degreesC for 6 days or at 5 degreesC for 2 weeks). This may indicate that sensitivity of coriander to ethylene is reduced at low temperature. These results suggest that ethylene plays a significant role in senescence of coriander leaves; commercial use of 1-MCP may enhance coriander quality under suboptimal postharvest conditions. (C) 2002 Elsevier Science B.V. All rights reserved.