Cytosolic invertase that specifically cleaves sucrose into glucose and fructose and is involved in the regulation of multiple tissue development including primary root elongation, root hair growth, leaf and silique development, and floral transition (PubMed:17220200, PubMed:19470642, PubMed:21441406, PubMed:25256212). Is involved in osmotic stress-induced inhibition on lateral root growth by controlling the concentration of hexose in cells (PubMed:17508130). May regulate sugar-mediated root development by controlling sucrose catabolism in root cells (PubMed:17220200). Contributes to carbon partitioning and cellulose biosynthesis in seedlings (PubMed:29569779). Hydrolysis of terminal non-reducing beta-D-fructofuranoside residues in beta-D-fructofuranosides. Optimum pH is 7.0-8.0. Optimum temperature is 9 degrees Celsius. Forms homohexamers (PubMed:32134001). Interacts with PIP5K9 (PubMed:17220200). Interaction with PIP5K9 represses CINV1 activity (PubMed:17220200). Interacts with GRF1, GRF2, GRF3, GRF4, GRF5, GRF6, GRF7, GRF8 and GRF10; these interactions are dependent of the phosphorylation at Ser-547 (PubMed:25256212). Detected in membrane and nucleus when associated with PIP5K9. A number of isoforms are produced. According to EST sequences. Expressed in radicle, hypocotyls, root tips and vascular cylinder, leaf vasculature, shoot stipules, trichomes, stem, stigma apex and base of siliques. Induced by mannitol in roots (PubMed:17508130). Induced by hydrogen peroxide (PubMed:21441406). Induced by dark-to-light transition in roots (PubMed:25256212). Phosphorylated at Ser-547 by CPK3 and CPK21. Reduced primary root length and increased length and number of lateral roots. Reduced plant growth and early flowering. Reduced seedling levels of glucose and fructose, but increased levels of sucrose. Belongs to the glycosyl hydrolase 100 family.