Involved in the regulation of pedicel length and of CLAVATA pathways controlling stem cell identity at shoot and flower meristems. H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Binds 2 magnesium or manganese ions per subunit. Expressed in roots, leaves, stems, inflorescences, flowers and developing vascular tissue. The conserved PP2C phosphatase domain (257-736) is interrupted by an insertion of approximately 200 amino acids. Loss-of-function mutant pll1-1 (T-DNA insertion) shows suppression of clavata mutant phenotypes. Redundant with POL. Pol and pll1 double mutant inis seedling lethal. Belongs to the PP2C family. Truncated N-terminus. Intron retention.