EFFECT OF ETHYLENE PRODUCING SUBSTANCES AND CULTAR ON SOME ORNAMENTAL PLANTS

Attempts were made to compare the influence of ethylene producing substances - ethrel, dextrel and kamposan with that of cultar in respect to chrysanthemum (Chrysanthemum coreanum, cultivar "Jantar"), phlox and dahlia. They were treated with ethrel, kamposan (1000 ppm), dextrel (5000 ppm) and cultar (25–50 ppm, trade name of paclobutrazol in USSR, ICI, England); as a surfactant tween-80 was applied. The plants were sprayed at the very beginning of vegetation when their height was 20–25 cm; the spraying was performed three times with a week interval. The treatment with ethylene producing substances resulted in a 40% growth decrease as compared to controls at the beginning of development. Then the inhibitory effect stopped, so at the vegetation end the stem length was the same as with untreated plants. Ethrel and kamposan inhibited flower initiation very strongly (30–40 days). So, it is impossible to use ethylene producting substances for obtaining pot-bedding cultures of examined plants. The cultar treatment reduced stem height (50% compared to control plants). It delayed flowering for 3–5 days; a shorter period of inflorescence was observed after this substances application. Cultar continued its inhibitory action for 2 years after one year of treatment. Cultar is a very good substance for obtaining dwarfed form and therefore good for pot-bedding culture.

As a result is it becoming possible to transplant the plants from field to greenhouse and vice versa.