Hydrolyzes only phytoceramide into phytosphingosine and free fatty acid (PubMed:25619405). Does not have reverse activity (By similarity). Affects plant morphogenesis. Required for the formation of wax layer that ensure cuticle permeability. Implicated in abscisic acid (ABA)-mediated stomatal closure. Involved in both biotic and abiotic stresses. Promotes salt resistance and defenses responses toward pathogenic bacteria (e.g. P.syringae) and against the fungal toxin fumonisin B1 (FB1) (PubMed:25619405). Mostly expressed in roots, shoot meristems and pollen, and, to a lower extent, in mature leaves. Pleiotropic phenotypes, including reduction of leaf size, dwarfing, small flowers and an irregular wax layer. The abnormal wax layer is associated with higher water loss and rapid chlorophyll leaching due to an increased cuticle permeability. Increased phytoceramides levels and decreased long chain bases. Increased sensitivity to salt stress. Increased susceptibility to the pathogenic bacteria P.syringae with reduced pathogenesis-related (PR) genes induction. Reduced sensitivity to abscisic acid (ABA) leading to impaired stomatal closure regulation. Increased sensitivity to the fungal toxin fumonisin B1 (FB1)-induced cell death. Belongs to the alkaline ceramidase family.