Catalyzes the first irreversible reaction from fructose-1,6-bisphosphate to fructose-6-phosphate and inorganic phosphate and plays an important regulatory role in sucrose biosynthesis and metabolism (Probable). Its activity is essential to regulate starch levels (PubMed:25743161). Functions in fructose-mediated signaling independently of its catalytic activity in sugar metabolism. May act downstream of ABA2/GIN1, which is involved in abscisic acid (ABA) synthesis to regulate autotrophic transition and modulate early seedling establishment after seed germination (PubMed:21253566). beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate Binds 3 Mg(2+) ions per subunit. Slight decreased in growth rate. In plants there are two FBPase isozymes: one in the cytosol and the other in the chloroplast. Belongs to the FBPase class 1 family.