Effect of gibberellic acid on starch content of soybean (Glycine max L.) and its correlation with extension growth

Abstract

This investigation was undertaken to study the effect of GA₃ on extension growth of Glycine max L. and on starch content of its individual internodes at maturity. The effect on hydrolytic activity of the extract of different internodes was also studied. GA₃ stimulates the extension growth of stem by increasing the elongation of those internodes which are either in the process of elongation or being differentiated at the time of treatment. Starch content decreases with the position of the internode (from base upwards) on the intact plant. Corresponding internodes have minimum starch content in 100 ppm GA₃-treated plants and maximum in the controls. Internodes which show the maximum elongation due to GA₃ treatment, show the least starch content and also show maximum hydrolytic activity during the period of elongation. It is suggested that enhanced extension growth is brought about by enhanced mobilization of reserve food by GA₃.