Biochemical Responses of Lead in Cowpea (Vigna unguiculata (L.) Walp.)

Soil contamination with persistent metal Lead (Pb) is a grave concern to be addressed at the global level, since it poses danger of entering in to the human food chain. The present study is an endeavor to assess the biochemical impact of Lead (Pb) on one commonly used vegetable, Cowpea (Vigna unguiculata (L. ) Walp). Field studies were conducted from seed to seed to investigate the biochemical responses of cowpea to sole application of different levels of Pb (100M, 500M, 1mM, 5mM and 10mM). Applications of Pb caused accumulation Pb in root, stem, leaves and pod. The Pb storage in different regions were in the sequence of root greater thanfruitgreater thanstemgreater thanleaves. Generally the higher doses of Pb clearly blocked and the lower doses accelerated the uptake and translocation of Ca, Mg, Fe, Cu, Zn and Mn. The total protein, total carbohydrate, number of stomata, stomatal index, length and width of stomata were positively affected by the lower levels of Pb (up to 500M or 1mM and even 5mM of Pb) and negatively affected by its upper level (10mM). However, Pb adversely affected the leaf area in all its treatment.