8 pages, Commercial, Industrial and agricultural wastes are major soil pollutants, which contain inorganic, organic compounds and heavy metals. When these heavy metals accumulate in agricultural lands, they adversely affect on growth and physiology of crops ultimately causing decrease in food productivity. In this experiment maize was used to investigate the effects of heavy metals on plant physiology and growth. Maize is cultivated throughout the world for its importance as cereal. It is the third most important cereal crop, following wheat and rice. Maize is a significant food source for humans providing essential minerals, vitamins, carotene and ascorbic acid. Apart from its importance as a cereal source, it also serves as important raw material for various products such as syrup, starch and oil. Various concentrations of Cr and Mn were applied individually as well as in combination to examine their effects on growth and physiology of maize. Analysis of recorded data showed that the treatment 0.5 mM MnCl2 + 0.25 mM CrCl3 had the most harmful effect and caused significant decrease in height, number of leaves and chlorophyll 'a' and 'b' in the stems and leaves. While less harmful effects were seen when heavy metals were applied individually such as 0.25 mM CrCl3, 0.25 mM MnCl2 and 0.5 mM MnCl2 as these treatments did not significantly impact on height, leaf area and chlorophyll content in stems and leaves. So, from these results it can be concluded that. when chromium was applied separately, it had minimal impact on plant physiology and growth, but in combination with manganese, it severely affected on maize plants. Similarly, a small concentration of manganese alone did not affect plant growth, but combined with chromium, it negatively impacted photosynthetic pigments and growth traits.
