engleski

The effect of cadmium on mitotic index in three maize genotypes

Cadmium is a non-essential metal toxic to plants and animals. It is present in varying concentrations in soil and increased levels of cadmium negatively affect plants. In order to investigate the effects of increased levels of cadmium on mitotic index of the root, seeds of three maize genotypes with different cadmium accumulation were planted (B84, Os6-2 and their hybrid). Uncontaminated soil was used for the control treatment (approximately 0.2 mg Cd/ kg soil) and for the increased cadmium level treatment soil was contaminated with cadmium chloride (CdCl2) up to 5 mg Cd/ kg soil. Mitotic index was calculated as number of cells undergoing mitosis/total number of cells*100%. To determine cadmium uptake in the above ground parts of the plants cadmium concentration in ear- leaves was measured (by ICP-OES). Results of ICP analysis for cadmium have shown that in contaminated soil B84 line has a very low cadmium accumulation in leaves (1.321 mg Cd/kg dry weight), Os6-2 line has high cadmium accumulation in leaves (10.321 mg Cd/kg dry weight) and hybrid is in-between the two maize lines in cadmium accumulation in leaves (5.137 mg Cd/kg dry weight). Mitotic indices of B84 line and hybrid did not show reduction in contaminated soil (control - 13.64%, contaminated soil 12.4%, control - 27.17%, contaminated soil 26.89%) while Os6-2 line showed a large reduction in mitotic index in contaminated soil (control - 38.8%, contaminated soil - 6.11%) which suggests inhibition of root growth in Os6-2 line and a certain degree of tolerance in hybrid and B84 line.

maize ; cadmium ; heavy metals ; stress ; mitotic index

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