Evaluation of the role of hormonal factors in secondary growth of dicots

The present investigation was carried out with a view to finding out the role of hormonal factors in secondary growth in stems ofCapsicum annuum andSolanum melongena. Seedlings were treated with aqueous solutions of growth substances and observations were made in respect to initiation of cambium, magnitude of secondary growth and differentiation of the secondary vascular tissues. Enhancement of secondary growth by auxins (IBA, IAA and NAA) and its partial or complete inhibition by auxin inhibitors (MH, PMN and DCA) clearly establishes the controlling nature of auxins on the process. Evidence has been presented demonstrating that auxins are more involved with differentiation of xylem, whereas GA is more involved with phloem. The investigation may be of economic value in improving the quality and quantity of wood.