## 2 Results  
### Fresh and Dry Weights of Different Parts  
The effect of Pb, Cu and Cd on _Vicia faba_ (common bean and faba bean) plants was evaluated by monitoring the growth of shoots and roots., based on the fresh weight of the shoots (leaves and stems) and roots (abbreviated as SFW and RFW, respectively) at different stages of growth planted in substrate (Table 1). It was seen that the growth of the roots was more sensitive to the uptake of the HMs, vis-a-vis that of the shoots (Figures 1 and 2). Among the three HMs, Cd inhibited growth the most in both shoots and roots in both common bean and faba bean, at all the different growth stages.  
In the common bean samples, the SFW values were significantly reduced at all the growth stages, vis-a-vis the control plants (which were not subjected to HM-treatments). At the vegetative growth stage, the SFW varied from 4.61 g (Cd-treated plants) to 8.14 g (control plants). Plants which were exposed to Pb recorded 5.51 g (20% greater than those exposed to Cd). The decrease in the fresh weight of the shoots manifested itself in smaller sizes of the leaves for both common bean and faba bean.  
During the flowering stage, the per-plant SFW values for common bean ranged between 20 and 26 g, while those for faba bean were much higher, from 67.65 to 76.63 g. The lowest in both these ranges were recorded by the plants treated with cadmium, while the highest belonged to the respective controls (Figure 1). At the stage of full-fruiting (green pods), SFW did not vary much among the treatments, though significant differences were observed vis-a-vis the respective control values. If common bean and faba bean are compared, smaller differences were observed--common bean plants had a lower number of large pods with 5-7 seeds, while faba bean plants had a higher number of small pods with 8-10 seeds per pod.  
The fresh weight of roots (Figure 2) registered a much greater decrease with respect to the controls, for common bean vis-a-vis faba bean for all three HMs, with Cd affecting  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & **Clay** & **Limon** & **Sand** & **pH** & **OM (\%)** & **Carbon** & **Nitrogen** & **Lead** & **Copper** & **Cadmium** \\  & **(\%)** & **(\%)** & **(\%)** & **pH** & **OM (\%)** & **(\%)** & **(g/kg)** & **(ppm)** & **(ppm)** & **(ppm)** \\ \hline Concentration & 38.7 & 27.19 & 34.54 & 7.07 & 57.33 & 33.87 & 11.31 & 0.01 & \textless{}0.15 & 0.01 \\ \hline \end{tabular}
\end{table}
Table 1: Physico-chemical characteristics of the substrate used in this study.  
Figure 1: Response of bean plants (**A**) (a, b, c, d) and faba bean plants (**B**) (a, b, c, d) to HM treatments at different stages of growth, depicted for the fresh weight of the shoots (leaves and stems).  
Figure 2: Response of bean plants (**A**) (a, b, c, d) and faba bean plants (**B**) (a, b, c) to HM treatments at different stages of growth, depicted for the fresh weight of the roots.  
the growth the most, while Cu and Pb had almost similar negative effects for both the varieties. Fresh weight of roots in vegetative, flowering and pod stages significantly decreases (\(p<0.001\)) in treated plants, an effect that is more pronounced in common bean than in faba bean with respect to the control. In addition these findings show that Cd has strong negative effects on root growth indicating their sensitivity compared to the growth of shoots and fruits. These results indicate that in general the highest concentrations of metals are accumulated in roots after than in aerial parts especially in bean plants.