Maize is ranked as the third most important cereal crop of the world which was used as food and fodder for both humans and animals. Hybrid maize cultivars worldwide replaced the traditional cultivars due to their high yield and stress tolerance. The use of amino acid-micronutrients in the form of chelates is recently introduced to cope with heavy metal stress in crop plants. The present work was planned to elaborate the effect of foliar application of Zinc-Lysine chelate on the growth, biochemical attributes, ion balance and rhizospheric properties of hybrid maize under cadmium stress. A pot experiment was conducted in the green house which contains 5 kg of soil and 80 µg/kg CdCl2. Two maize cultivars 3062 and 31P41 were obtained and sown 15 plants per pot. The Zn-lys concentrations (0, 2, 4, 6 & 8 mg/L) was applied foliarly at the 2nd, 5th and 7th week of the cultivation. Foliar application of the Zn-lys showed the remarkably high growth in both maize cultivars as compared with control. Zn-lys fertigation not only reduced Cd uptake by roots but also reduced its translocation in shoots and leaves. It also increased the root and shoot concentrations of ions i.e. Zn, Fe, P, N and K. Zinc-Lysine application also significantly increased the rate of photosynthesis, enzyme activities, plant biomass and nutritional status in both cultivars. The MDA and H2O2 were decreased and activity of SOD, POD, ascorbic acid, carotenoid and total protein was increased. However the Cd stress tolerance was more prominent in 3062 as compared with 31P41 and the most effective foliar concentration of Zn-Lys was 8 mg/L which was strongly recommended for amelioration of Cd toxicity.
Key Words: Maize, Rhizosphere, Ion dynamics, Zn-lys fertigation, Cd tolerance