Fuente: WIPO "tomato" The objective of the invention is to provide a plant activator with superior plant growth-promoting effect and low toxicity and soil contamination. A plant activator comprising, as an active ingredient,



a hydroxy fatty acid derivative of general formula (I) and/or (II):










(wherein, R1 is a straight or branched hydrocarbon group with 4 to 12 carbon atoms, optionally comprises one or more double bonds and/or OH groups, and the position of the double bond is not limited, provided that the double bond is comprised, and R2 is a straight or branched hydrocarbon group with 2 to 8 carbon atoms, optionally comprises one or more double bonds and/or OH groups, and the position of the double bond is not limited, provided that the double bond is comprised) or a salt or an ester thereof.