Has phosphatase activity toward Ins(1,4,5)P3 (PubMed:15574849). Controls Ins(1,4,5)P3/Ca(2+) levels that is crucial for maintaining pollen dormancy and regulating early germination of pollen (PubMed:22573619). 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate Mostly expressed in leaves and flowers and only weakly expressed in roots, stem and young seedlings. More precisely detected in cotyledon tips, hydathodes of leaves and mature pollen grains. Not induced by stresses. Precocious pollen germination within anthers. Hypersensitivity to abscisic acid (ABA) during seed germination. Elevated levels of Ins(1,4,5)P3 and cytosolic Ca(2+). Belongs to the inositol polyphosphate 5-phosphatase family.