Interaction of triapenthenol and environmental factors on the growth and flower bud formation of Gardenia jasminoides Ellis

Abstract

The interaction effects between total solar radiation, air temperature and relative humidity with different concentrations of the plant growth regulator triapenthenol (Baronet) on the vegetative growth and the formation of flower buds of potted gardenia (Gardenia jasminoides Ellis) plants were studied in glasshouse experiments.Triapenthenol was applied as a soil drench at concentrations of 0, 70, 140 and 280 mg L–1 to plants under each of three radiation levels of about 250 (P1), 90 (P2) and 25 (P3) Wm−2. It was established that the maximum temperature was the most critical environmental factor to plant development at all radiation levels. Lengths of new lateral shoots after pinching and the number of flower buds/plant were significantly reduced when radiation was reduced and triapenthenol concentrations increased. The interaction between total radiation and triapenthenol concentration significantly affected the number of flower buds/plant. An increase in triapenthenol concentration and a reduction of total radiation caused increased wrinkling of the leaves.In the unshaded plot (P1), the 140 mg L−1 triapenthenol concentration produced high-quality plants that were shorter than the untreated ones with more flower buds/plant during the growth period. In the moderately shaded plot (P2), the best market-quality plants were those treated with 70 mg L−1 triapenthenol. Key words: Gardenia jasminoides, temperature, total solar radiation, triapenthenol, relative humidity