Effect of Phytohormones Pretreatment on Physiology of Seed Germination in Withania Somnifera

The present study was undertaken to examine the physiological changes occur in seed germination due to the effect of growth hormones in a medicinal plant viz. Withania somnifera var. Poshita and Jawahar-20 under laboratory condition. Combination of growth hormones, ranging from 25-150ppm (viz. GA₃IAA and IB A) with different soaking period were used to evaluate the rate of germination. 125 ppm GA₃ with 24hrs soaking time enhanced the rate of germination of both Poshita (63.33%) and Jawahar-20 (76.66%). IAA and IBAwere not as effective as GA₃ for physiological changes in the seed germination. During germination the plumule and radicle length were increased with increasing concentration of growth hormones. Activities of most important hydrolyzing enzymes a-amylase and protease were also determined at 1^st, 5^th and 10^th day in 125ppm GA₃ treated seeds, a-amylase was increased significantly and maximum at 10^th day in both the varieties but the activity of protease was highest at 5^th day thereafter it was decreased.