Altered levels of metabolites under the influence of nickel in green gram

Greengram [Vigna radiata (L.) Wilczek] cv K851, was grown with complete nutrient solution for 30 days. On 31^st day, pots with plants were divided into four lots. One lot was allowed to grow and treated as control. In other three lots, nickel was supplied as NiSO₄ at 0.1, 0.2 and 0.5mM. At d 35 (5 days after treatment), visible symptoms of excess Ni exhibited as chlorosis on young leaves at 0.5mM Ni and resembled with those of iron deficiency. The chlorosis later intensified and covered some of the middle leaves. Some brown necrotic irregular spots developed on both sides of the main veins on affected leaves, which were severely chlorotic. Compared to the control, reducing, non-reducing, total sugars, starch, phenols and non-protein nitrogen increased, whereas, concentration of protein nitrogen decreased with an increase in nickel supply. The accumulation of nickel was higher in roots than other plant parts.