Calcium and calmodulin inhibitor effects on the growth of carrot (Daucus carota L.) and radish (Raphanus sativus L.) in nutrient culture

Growth of carrot and radish seedlings in nutrient culture was inhibited by pretreatment with three calmodulin inhibitors. There was little selective effect on specific organs, shoots, tap root and fibrous roots over a range of concentrations. Although pretreatment with CaCl₂ (0.5 mM) did not affect growth of untreated seedlings, it partially reduced the inhibitory effects of trifluoperazine over the concentration range 0.01–0.05 mM. Trifluoperazine reduced the growth of GA₃-treated seedlings but did not overcome the modifying effect of GA₃ in favouring shoot/root ratio; ABA exacerbated its inhibitory effect on overall seedling growth and particularly on tap root development.Abbreviations GA₃ gibberellic acid - ABA abscisic acid - CaCl₂ calcium chloride - GAs gibberellins - Tfp trifluoperazine