Study of Chlorophyll Pigments in Beans (Phaseolus vulgaris) in terms Of Heavy Metal Complexation with Various Forms of Sulfur, in Order to Reduce Their Toxicity

In this paper we intended to find the effect of the complexation of heavy metals with various forms of sulfur on the content of chlorophyll pigments in dwarf beans ( Phaseolus vulgaris var. Compressius ellipticus ). The effect of two heavy metals, cadmium and respectively lead, in different concentrations, on the content of chlorophyll pigments in the leaves of beans plantlets, by extracting the pigments by the hot process. These were the variants: V 1 Cd 1mg/l, V 2 Cd 1mg/l + 100mg Cys, V 3 Cd 1mg/l + 100mgK 2 SO 4 , V 4 Cd 50mg/l, V 5 Cd 50mg/l+100mg Cys, V 6 Cd 50mg/l+100mgK 2 SO 4 , V 7 Pb 1mg/l, V 8 Pb 1mg/l+100mg Cys, V 9 Pb 1mg/l+100mg K 2 SO 4 , V 10 Pb 50mg/l, V 11 Pb 50mg/l+100mg Cys, V 12 Pb 50mg/l+100mg K 2 SO 4 , V 13 – control sample. Following the experimental research, we can state that the contents of chlorophyll pigments in leaves is negatively influenced by organic sulfur (cysteine) and positively influenced by inorganic sulfur (K 2 SO 4 ), towards inhibition and, respectively, stimulation. Cysteine inhibits with 7% at high concentration of Cd (50mg/l), and K 2 SO 4 stimulates with 1.2% at the same concentration of Cd. In case of Pb (1 mg/l), cysteine inhibits it with 5%, and inorganic sulfur with 1% less as the control. Inorganic sulfur in combination with high concentration of Pb stimulates the pigments production in leaves with 3% more than the control, and concentrated Cd inhibits it with 15%.