Plant lipoxygenase involved in a number of diverse aspects of plant physiology including growth and development, pest resistance, and senescence. May not be involved in the bulk production of jasmonate upon wounding. Catalyzes the hydroperoxidation of lipids containing a cis,cis-1,4-pentadiene structure. Linolenic acid is the preferred substrate, before linoleic and arachidonic acids. Has also some activity with phosphatidylglycerol, but not with galactolipids. (9Z,12Z)-octadecadienoate + O2 = (13S)-hydroperoxy-(9Z,11E)-octadecadienoate (9Z,12Z,15Z)-octadecatrienoate + O2 = (13S)-hydroperoxy-(9Z,11E,15Z)-octadecatrienoate Binds 1 Fe cation per subunit. Optimum pH is 7.0. Lipid metabolism; oxylipin biosynthesis. Monomer. Associated with the non-appressed part of the thylakoid membrane. Expressed in leaves and floral buds. Up-regulated by jasmonate and abscisic acid treatment. Up-regulated localy and systemically at the transcript levels 6 hours after wounding, but the protein levels remain constant. Not induced by pathogen infection. 99% depletion of LOX-H1 by co-suppression-mediated gene silencing has no effect on the basal or wound-induced levels of jasmonates but results in a marked reduction in the production of volatile aliphatic C6 aldehydes. Belongs to the lipoxygenase family.