GROWTH RESPONSE OF MAIZE (ZEA MAYS L.) TO METAL TOXICITY

Abstract

This study evaluated the phytotoxic effects of lead (Pb) and zinc (Zn) as Pb(NO3)2  and Zn(NO3)2 on maize  (Zea mays L) considering the  plants’ growth indices, biomass as well as soil parameters and soil microorganisms after treatment. The results showed that plant growth significantly reduced with increasing concentrations (100,150 and 200 mgkg-1) of Pb and Zn contamination. The results indicated significant inhibitory effect on the growth parameters (stem height, root length, leaf area, fresh and dry weight) measured, compared to control experiment. This study therefore revealed that the heavy metals have harmful effects on maize’s growth.  Consequently, the consumption of such contaminated cereal by man and animals can lead to their death after the metals have biomagnified in their systems. Lead and Zn application in general, affected the vegetative growth; both fresh and dry weights were reduced with increasing concentrations of the metals. These results show that these metals are toxic to human and animal health. As a result, farmers should be encouraged to use water from good source for irrigation and also cultivate on metal-free soils if possible to save lives.