May be involved in the control of plant responses to environmental stresses. Highly expressed in leaf sheaths and leaf collars. Induced by cold, salt and drought stresses. Induced by abscisic acid, auxine, brassinosteroid, ethylene, gibberellin, jasmonate, kinetin, reactive oxygen species and salicylate. Plants over-expressing CYL4 exhibit reduced tolerance to cold, salt and drought stresses. Belongs to the Cyclase 1 superfamily.