Regulation of excessive vegetative growth is of importance in both field and bedding plant production. The goal of the study was to evaluate the effect of preplant seed soaking in growth regulators on the growth control of floricultural (verbena, salvia, pansy, marigold, celosia) and agronomic (cucumber, dill) crops. Seeds were soaked in water solutions of growth regulators of different concentrations ranging according to the crop from 50 to 1000 mg·L-1 for paclobutrazol, 1 to 10 mg·L-1 for uniconazole, 10 to 200 mg·L-1 for ancymidol, 100 to 5000 mg·L-1 for chlormequate chloride and dried at 20 °C for 24 h prior to sowing into plugs. In the first experiment, seeds of verbena, salvia, pansy, and dill soaked for 5 minutes in 50 mg·L-1 paclobutrazol solutions produced seedlings that were up to 43, 18, 30, and 22% shorter than the controls, respectively. Increased paclobutrazol concentrations and soaking time generally corresponded to a greater reduction of plant height, as well as delays and reduction in seedling emergence of all crops, except cucumber. In the second experiment, growth of marigold plugs from seeds soaked in 5 mg·L-1 uniconazole or 60 mg·L-1 ancymidol solutions during 45 min was associated with 23% or 6% plant height reduction, respectively. Soaking of marigold seeds in the solutions of chlormequate chloride did not significantly affect seedling growth. Increasing time of seed soaking in growth regulator solutions did not influence emergence of marigold seedlings. The height of celosia seedlings was only slightly reduced by soaking seeds in the solutions of all studied growth regulators. Results indicate that seed treatments with growth regulators might be useful in growth control of selected bedding plants.
Early Growth Control of Plants by Seed Soaking in Growth Regulator Solutions
