What determines the growth of a plant in height?

Cell length directly affects plant growth and leaf and seed size. The researchers identified two proteins, PRE1 and ACE, which act as a positive regulator for cell elongation, and one protein, AtIBH1, that inhibits cell elongation. They found that ACE directly induces cell elongation, while AtIBH1 inhibits ACE activity by interacting with it. PRE1 indirectly promotes elongation by interfering with AtIBH1 activity. The final cell length is determined by the balance between the three proteins.