Effects of 4-(Indole-3)-Butyric Acid, Light Intensity and Terminal Buds in Vegetative Propagation of Some Species of Hibiscus

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Kachecheba, J.L.
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The effects of 4-(indole-3)-butyric acid (IBA), light intensity and terminal buds were examined on the formation and growth of callus and (or roots in stem cuttings of five species of Hibiscus. The rate of volume growth of callus increased with increasing concentration of IBA, but the volume ultimately attained was not altered. The number and dry weight of roots formed on a cutting, increased, but at a declining rate, and the dry weight per root decreased as the concentration of IBA increased from 0 to 10,000 ppm. The number of roots formed was significantly affected by IBA but not by light intensity falling on cuttings. Cuttings which were obtained from plants that had been grown in dim light formed significantly more roots than those which were obtained from plants grown in bright light, irrespective of IBA concentration. The effect of IBA was smaller in cuttings with than in those without terminal buds. It is suggested that plants grown in dull light contained more endogenous auxin than those grown in bright light and also that cuttings with buds ,contained so much endogenous auxin that on treating them with 8,000 ppm IBA the total level of auxin exceeded the optimum and inhibited rooting.
East African Agricultural And Forestry Journal, 41 (1), pp. 22-34