Description
1-methylcyclopropene is a plant growth regulator used to extend the life of cut ornamentals. It is moderately soluble in water, highly volatile and has some potential for leaching to groundwater. It is not persistent in soil systems but may, under certain conditions, persist in aquatic systems. It has no herbicidal activity. It is relatively non-toxic to mammals, although it may bioaccumulate. There are gaps in knowledge regarding its toxicity to biodiversity but there is data showing that it is moderately toxic to fish and algae. It is highly toxic to earthworms.
Chemical Properties
1-Methylcyclopropene (1-MCP) is a derivative of cyclopropene, a small cyclic olefin with active chemical properties. 1-MCP is a synthetic plant growth regulator and is now widely used in commercial applications.
Uses
1-Methylcyclopropene (1-MCP) is a plant growth and ripening regulator. It acts as an inhibitor of ethylene by blocking the receptor of ethylene in the tissues of plants, flowers, fruit and vegetables, thus preventing the ripening process. It is used to inhibit ethylene production in cut flowers, potted flowers, bedding, nursery and foliage plants, and in stored fruits and vegetables. It is approved for use only in enclosed spaces, such as greenhouses, store rooms, coolers, enclosed truck trailers, controlled atmosphere food storage facilities, and shipping containers.
Definition
ChEBI: A member of the class of cyclopropenes that is cyclopropene in which the hydrogen at position 1 has been replaced by a methyl group. A gas at room temperture and pressure, it is a (synthetic) ethylene perception inhibitor and is used to prolong the life of
cut and potted flowers, other ornamental plants, and fruit.
Production Methods
1-methylcyclopropene is synthesised through a multi-step chemical process that begins with the reaction of 3-chloro-2-methylpropene with sodium hydride in toluene under an inert nitrogen atmosphere. The sodium hydride, typically coated in mineral oil, acts as a strong base to initiate cyclisation. The mixture is stirred at a controlled temperature of 25–30 DegC for about two hours, during which a light yellow precipitate of 1-MCP sodium salt forms. This intermediate is then filtered and washed with toluene to remove residual reactants and by-products. The final step involves decomposing the sodium salt in water to release pure gas
Health effects
Based on studies with laboratory animals, no adverse effects are expected to humans who are exposed to end products that contain 1-MCP, although eye irritation may occur if a user does not follow label directions. 1-MCP as a gas is not toxic to test animals. Human exposure is expected to be minimal because 1-MCP is approved only for use indoors, and the product label instructs people to leave the treatment space during treatment.
Mechanism of action
Inhibits the effects of ethylene on ripening
Regulations
Methylcylcolpropene (1-MCP) was registered as an active ingredient in April 1999. As of March 22, 2006, there are five registered products that contain this active ingredient. The EPA established an exemption from the requirement of a tolerance for residues of 1-MCP in or on fruits and vegetables when used as a post harvest plant growth regulator, i.e., for the purpose of inhibiting the ripening promotion effects of ethylene. This tolerance exemption became effective July 26, 2002 (67 FR 48796). At that time, EPA registered a new product allowing for post-harvest application to apples, apricots, avocados, kiwifruit, mangos, melons, nectarines, pears, papayas, peaches, persimmons, plums, and tomatoes.
Pesticide Type
Plant Growth Regulator
