Plant activator

Abstract

An object of the present invention is to determine novel means of activating plants; more particularly, means of controlling plant growth, such as means of promoting growth, means of controlling dormancy, means of imparting tolerance against stress for plants (dryness, high or low temperatures, osmotic pressure, etc.), and means of preventing aging. The present inventors have found that the above object can be achieved by providing plant activators containing, as an active ingredient, C 4 -C 24 ketol fatty acids, in particular, 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid.

1 - 9 . (canceled) 
     
     
         10 . A method of promoting growth of a plant comprising applying to the plant a C 4 -C 24  ketol fatty acid, wherein the C 4 -C 24  ketol fatty acid is applied to the plant during seedling or after germination of its seeds. 
     
     
         11 . The method according to  claim 10 , wherein the C 4 -C 24  ketol fatty acid contains a carbon atom constituting a carbonyl group and a carbon atom connected to a hydroxyl group, one of the above carbon atoms being located at the α or γ position with respect to the other carbon atom. 
     
     
         12 . The method according to  claim 10 , wherein the C 4 -C 24  ketol fatty acid contains one to six carbon-carbon double bonds, such that the number of the double bonds does not exceed the number of carbon-carbon bonds in the ketol fatty acid. 
     
     
         13 . The method according to  claim 10 , wherein the ketol fatty acid contains 18 carbon atoms, and two carbon-carbon double bonds. 
     
     
         14 . The method according to  claim 10 , wherein the C 4 -C 24  ketol fatty acid is 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid. 
     
     
         15 . A method for treating dormancy of a plant comprising applying to the plant a C 4 -C 24  ketol fatty acid, wherein the C 4 -C 24  ketol fatty acid is applied to the plant after germination of its seeds or to a dormant plant. 
     
     
         16 . The method according to  claim 15 , wherein the C 4 -C 24  ketol fatty acid contains a carbon atom constituting a carbonyl group and a carbon atom connected to a hydroxyl group, one of the above carbon atoms being located at the α or γ position with respect to the other carbon atom. 
     
     
         17 . The method according to  claim 15 , wherein the C 4 -C 24  ketol fatty acid contains one to six carbon-carbon double bonds, such that the number of the double bonds does not exceed the number of carbon-carbon bonds in the ketol fatty acid. 
     
     
         18 . The method according to  claim 15 , wherein the ketol fatty acid contains 18 carbon atoms, and two carbon-carbon double bonds. 
     
     
         19 . The method according to  claim 15 , wherein the C 4 -C 24  ketol fatty acid is 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid. 
     
     
         20 . A method for enhancing tolerance of a plant against stress comprising applying to the plant a C 4 -C 24  ketol fatty acid, wherein the C 4 -C 24  ketol fatty acid is applied to the plant during or after germination of its seeds. 
     
     
         21 . The method according to  claim 20 , wherein the stress is dry stress. 
     
     
         22 . The method according to  claim 20 , wherein the C 4 -C 24  ketol fatty acid contains a carbon atom constituting a carbonyl group and a carbon atom connected to a hydroxyl group, one of the above carbon atoms being located at the α or γ position with respect to the other carbon atom. 
     
     
         23 . The method according to  claim 20 , wherein the C 4 -C 24  ketol fatty acid contains one to six carbon-carbon double bonds, such that the number of the double bonds does not exceed the number of carbon-carbon bonds in the ketol fatty acid. 
     
     
         24 . The method according to  claim 20 , wherein the ketol fatty acid contains 18 carbon atoms, and two carbon-carbon double bonds. 
     
     
         25 . The method according to  claim 20 , wherein the C 4 -C 24  ketol fatty acid is 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid. 
     
     
         26 . A plant activator which does not induce flower bud formation comprising:
 a C 4 -C 24  ketol fatty acid containing a carbon atom constituting a carbonyl group and a carbon atom connected to a hydroxyl group,   wherein one of said carbon atoms is located at the a position with respect to the other carbon atom.