determining the nickel toxicity on chlorophyll content, hill reaction and growth in maize seedlings

to assess nickel-induced toxicity in plants, zea mays seeds were germinated and cultured on nutrient solution with nickel concentrations of 0, 50, 100 and 200 μm for a period of two weeks. its effects on the growth, hill reaction and photosynthetic pigments content were then investigated. the fresh and dry weight of leaves and roots increased in 50 μm nickel, but decreased in 100 and 200 μm. the decline in length of root and shoot were observed by increasing nickel concentration. according to the results, root and shoot showed differential growth response to various nickel concentrations. nickel concentrations up to 100 μm caused increase in the content of chlorophyll a, but resulted in decrease at 200 μm nickel. no significant changes in chlorophyll b and carotenoids contents were observed. the rate of hill reaction, as the ability of chlorophyll a in the reaction center of psii680 to split water, decreased by increase in nickel concentration.