Root morphology of tomato and brinjal as influenced by Cr toxicity

A pot experiment was conducted to study the effect of chromium on root morphology of two important vegetables crops, viz., tomato (Lycopersicon esculentum) and brinjal (Solanum melongena), irrigated with water having four different concentrations of Cr (0.1, 0.5, 2.5 and 7.5 ppm). Plants irrigated with normal water were used as control (0 ppm). Presence of Cr in irrigation water adversely affected all the parameters used for characterizing root growth, namely, root biomass, root length, root surface area, root length density, root volume, number of root forks, crossings and tips. Root fresh weight of tomato decreased by 80% in 7.5 ppm Cr treatment as compared to control, while in brinjal, it decreased by 63% for the corresponding treatments. In case of root length density also, it decreased from 528.10 cm/m³/pot in control to 133.46 cm/m³/pot in 7.5 ppm treatment in tomato, and 428.76 to 176.31 cm/m³/pot in the corresponding treatments in brinjal. Similar trends were observed in all other morphological parameters including the number of root forks, crossings and tips. The reduction in all root parameters characters was more pronounced beyond the concentration of 0.1 ppm in tomato and brinjal. Over all, tomato was more sensitive to Cr than brinjal.