Ten-week-old potted A. mangium seedlings were subjected to a growth retardant, paclobutrazol (PP333), at
concentrations of 0, 0.5, 1, 4 and 12 gil. Four methods of application were tested namely S, soil drenching at
week 0; F1, foliar spray (potting soil protected from chemical) at week 0; F2, foliar spray (potting soil protected
from chemical) at week 0 and 6; and S+F, soil and foliar spray (potting soil exposed to chemical spray) at week
O. Plants were harvested after 12 weeks for various growth measurements. Height and leaf area increments,
transpiration and stomatal conductance were monitored at weekly intervals. Paclobutrazol was found to be
effective in reducing root and shoot growth, transpiration and stomatal conductance of the seedlings. Treated
plants had higher root to shoot ratios. The effects of the chemical increased with increasing concentration and
frequency of application for the foliar spray. The chemical was most effective when applied through the soil either
l7y drenching (S) or soil and foliar spray (S+F)
