EFFECTS OF A TRIAZOLE, UNICONAZOLE, ON SHOOT ELONGATION AND ROOT-GROWTH IN LOBLOLLY-PINE

Uniconazol, applied in an aqueous solution to 3-year-old loblolly pine (Pinus taeda L.) at the soil-stem interface, decreased height growth by up to 55% after one growing season without phytotoxic effects. Results suggest that uniconazol may be useful in controlling height growth of seedlings and seed-orchard trees. The triazoles uniconazol, paclobutrazol. and BAS011106W were tested for effects on loblolly pine root growth. Root-applied uniconazol consistently increased root growth of 1-year-old seedlings. At 100 mg.L-1, uniconazol increased the number of new roots and survival by 47 and 19%. respectively. The increase in survival of uniconazol-treated seedlings was not statistically significant, but the tendency is encouraging.