Gibberellins are promotory PGRs that produce a wide range of physiological responses. A key ability described is causing an increase in the length of the axis, which is utilized to increase the length of grape stalks . Internodal elongation is a function of the axis lengthening. In contrast, Cytokinins are primarily associated with cell division and overcoming apical dominance , Ethylene with senescence and fruit ripening , and Indole acetic acid (Auxin) with apical dominance and rooting .