JASMONATE PLANT HORMONES (AUXINS)
Jasmonic Acid, and its metabolites, is a plant hormone and is derived from
Linolenic Acid. It plays roles in regulating plant development and growth, including growth inhibition, senescence, tendril coiling (but obviously not in Lodgepole Pines), seed germination, flower development, flower form, flowering time, flower opening, the number of open flowers, and leaf fall. It also has a hand in tuber formation of potatoes, yams and onions.
It also plays a role in the wounding response and systemic acquired resistance. It acts as a defence chemical against insects, interfering with their digestive processes.
Jasmonic Acid can be converted into the ester Methyl Jasmonate within the plant, which plays similar roles in plant defence as Jasmonic Acid. Plants produce both chemicals in response to stress or damage. Methyl Jasmonate also signals to remoter parts of the plant (via propagation through the air) forearming them against similar damage or attack, so that they are prepared. But Methyl Jasmonate is a gas which is not very active in plants, but as a gas is able to waft over to nearby plants whereupon it diffuses into the pores of the leaves of nearby un-damaged plants, where, acted upon by water, it gets converted into the water-soluble Jasmonic Acid. The Jasmonic Acid then attaches itself to specific receptors in cells triggering the leafs defence mechanism.
Methyl Jasmonate can also induce ethylene formation. Ethylene, H2C=CH2, is a gas and plant hormone that enhances the ripening of nearby fruits.
See Fungal Attack and Resistance.