Effect of ethylene and 1-methylcyclopropene on chlorophyll catabolism in florets of broccoli
Y. Gong and J.P. Mattheis
Plant Growth Regulation. Volume 40, Number 1, 2003. Pages 33-38.
2003
บทคัดย่อ
Branchlets of broccli (Brassica oleracea L.) were used to examine ethylene-stimulated chlorophyll catabolism. Branchlets treated with: 1) air (CK); 2) 1 mL.L-1 of 1-methylcyclopropene (1-MCP) for 14 hours at 20 C; 3) 100 mL.L-1 ethylene ( C2 H2) for 5 hours at 20 C; or 4) 1-MCP + C2 H4 were stored in the dark at 20 0C for up to 3 days. Hue angle of controls decreased during the storage period, and 1-MCP treatment delayed this change. Yellowing of broccoli was accelerated by C2 H2 treatment, however, prior treatment with 1-MCP prevented degreening stimulated by C2 H4. Treatments did not result in differences in differences in lipoxygenaes activity, however, 1-MCP without ethylene resulted in reduced activity of chlorophyllase (Chlase) and peroxidase (POD). Exposure to C2 H4 stimulated Chlase activity and remained a higher level of POD activity. In 1-MCP + C2 H4 treatment, the activity of Pod was reduced and the increase of Chlase activity was delayed. The results suggested that chlorophyll in broccoli was degraded by the POD – hydrogen peroxide system normally, and C H induced the activity of Chlase and remained higher POD activity to accelerate yellowing. 1-MCP treatment delayed the yellow of broccoli due to the inhibition of POD and Chlase activities.