Inhibitors of ethylene responses in plants at the receptor level: Recent developments

Abstract

A number of organic molecules that appear to block the ethylene receptor have been discovered recently. For example, on irradiation with visible light, diazocyclopentadiene (DACP), gives rise to some potent but as yet unidentified inhibitor compounds. Some synthetic cyclopropenes have been shown to bind to the ethylene receptor and prevent the physiological action of ethylene for extended periods. Cyclopropene (CP). 1‐methylcyclopropene (1‐MCP) and 3,3‐dimethylcyclopropene (3,3‐DMCP) have been shown to prevent ethylene effects in a number of plants. As low a concentration as 0.5 nl l −1 of 1‐MCP is sufficient to protect carnation ( Dianthus caryophyllus ) flowers for several days against ethylene, and 0.7 nl l −1 1‐MCP or CP will prevent the ripening of banana ( Musa sapientum ) for 12 days at 24°C. Some plant organs require higher concentrations of these inhibitors. Complete inhibition of ethylene effects in pea seedlings requires treatment with 40 n1 1 −1 of 1‐MCP. These novel inhibitors appear to be suitable for many commercial applications including extending the vase life of cut flowers and the display life of potted plants. Since 1‐MCP apparently is non‐toxic at concentrations that are active, it may in future be available for regulating the ripening of fruits and preventing the deleterious effects of ethylene in vegetables.