Presowing application of gibberellic acid on seeds used for the mung bean bioassay, promotes root formation in cuttings

Abstract

Before sowing, seeds of mung bean ( Vigna radiata (L.) R. Wilcz) used for the rooting bioassay, were soaked in water or in a gibberellic acid (GA 3) aqueous solution. Later, the excised cuttings from stock plants of both categories were treated with an aqueous solution of growth regulators or nutrients. GA 3 induced a greater elongation of hypocotyl, but the total length and fresh weight of the shoot of stock plants from GA 3- and H 2O-treated seeds did not differ significantly. The application of GA 3 (10 −11–10 −3 M) resulted in a small increase in the number of adventitious roots formed, which was correlated to its concentration. However, when the cuttings were treated with indolebutyric acid (IBA), paclobutrazol (PBZ) or sucrose, significant positive interactions were observed between the effects of presowing application of GA 3 (10 −3 M) to seeds and the other treatments. Between the effects of GA 3 and Hoagland nutrient solution there was not a significant interaction. The data indicate that although the presowing application of GA 3 promoted root development in cuttings only in a small degree, it contributed significantly to the formation of more roots by increasing the responsiveness of hypocotyl tissues to indolebutyric acid, paclobutrazol and sucrose.