Dual source phytohormones involved in flowering of Spathodea campanulata P. Beauv.

Abstract

The process of flowering involves various hormones produced and translocated endogenously by plants. Exogenous applications of synthetic hormones have revolutionized the horticulture industry. In Spathodea campanulata floral part development occurs within water calyces, under watery fluid which is unique among flowering plants. The present study was carried out to identify plant hormones and quantify them from water calyx fluid, corolla and calyx tissues of S. campanulata in order to establish the role of water calyx and the bathing fluid as the exogenous source of hormones for floral development. Phytohormones viz., IAA, Kinetin and GA3 were identified and quantified by using RP-HPLC and were found to be present and occur in varying concentrations in the bathing fluid and in the floral tissues, exhibiting quantitative correlation to the process of flowering. It can be concluded that the flower development and flower opening in S. campanulata is also due the influence of phytohormones present in the calyx fluid besides the endogenous concentrations of tissues as an exogenous source of hormones. The present work provides the first preliminary evidence for the water calyx fluid as nature’s exogenous source of hormones for development of floral parts.