01. Alleviation of heavy metal stress by bioadsorbents

Environmental pollution is not a new phenomenon, yet it remains the world’s greatest problem facing humanity, and the leading environmental causes of morbidity and mortality. Man’s activities through urbanization, industrialization, mining and exploration are at the forefront of global environmental pollution. Huge amount of waste water, the effluent are released from all industries. Most of the effluents and wastes contain heavy metals in an amount sufficient enough to cause toxicity to crop plants (Khan and Siddhu, 2006). Wastewater may contain various heavy metals including Zn, Cu, Pb, Mn, Ni, Cr and Cd, depending upon the type of activities, it is associated with. The impact of copper sulphate (2mM, 4mM, 6mM, 8mM and and 10mM) on the morphometric, biochemical and enzymatic characteristics of Trigonella foenum-graecum L. was analyzed after 21 days. The reduction in all the growth characteristics and biomass accumulation was parallel with reduction in carbohydrate and pigment content. The protein content and nitrate reductase also decreased with increasing concentration of copper sulphate. An increased leaf nitrate, free amino acids, L-proline, peroxidase and catalase indicated the stress nature of the plant. Applications of low cost environment friendly bioadsorbent (Azolla) alleviate the stress caused due to heavy metal toxicity. A significant increase in germination percentage, growth, biochemical and enzymatic characteristics was noted in the bioadsorbent treated experimental plant than when they were treated with various concentration of heavy metal alone.