PROMOTIVE EFFECTS OF DCPTA ON SEEDLING DEVELOPMENT AND GROWTH OF RADISH

A radish (Raphanus sativus L. cv. Scarlet turnip white tipped) seedling growth test was developed to examine promotive effects of 2-(3,4-dichlorophenoxy)triethylamine (DCPTA) on seedling vigor and plant development. Compared with controls, seed treatment using 30-mu-M DCPTA significantly (P = 0.05) enhanced the rates of root and hypocotyl elongation and seedling dry weight. Enhanced hypocotyl development by DCPTA showed a significant linear correlation (r = 0.83) with the increased taproot yield of mature plants grown from DCPTA-treated seeds. The harvestable taproot yield and harvest index of plants grown from seeds treated with 30-mu-M DCPTA were increased 109% and 38%, respectively, as compared with controls. Incubation of radish seeds in 30-mu-M DCPTA with actinomycin-D, alpha-amanitin, amisomycin, or cordycepin significantly reduced DCTPA-mediated seedling growth. These results indicate that nuclear gene expression and translation of mRNA on 80S ribosomes are required for the acceleration of seedling development by DCPTA.