Length (cm) of leaves (a) and roots (b). Seedlings were grown for 14 days in a Hoagland modified complete nutrient solution (0) and treated for the last 2 days with HS concentrations of 0, 1 and 5 mg C L−1. The length of roots and leaves was expressed in centimetres. Values are means of three independent determinations (±SE). Letters above bars indicates significant differences (P < 0.05).