Effect of Iaa on the Growth, Physiological and Biochemical Characteristics in Catharanthus roseus (L). G. Don.

Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations among the plants and generally considered to modulate many physiological events in higher plants. An experiment was conducted to study the different concentration of IAA (50, 100, 150, and 200ppm) foliar spray on vegetative growth, physiological and biochemical constituents of Chataranthus roseus (L). G. Don. The application of IAA led to significant increase of vegetative growth characters such as shoot and root length, shoot and root fresh weights and dry weights, photosynthetic pigment, non photosynthetic pigment composition and total soluble protein, total soluble glucose, free amino acid, starch, leaf nitrate, NRA and peroxidase activity. On unit fresh weight basis, the total chlorophyll content was found to increase at all concentrations. The optimal concentration for increased overall plants growth was found to be around 150 and 200ppm. Thus the exogenous application of IAA intact Chataranthus seedlings was found to be beneficial in promoting growth and biochemical responses in higher plants.