Vol. 7, Issue 7 (2018)

Author(s):
Sushree Sangita Barik and Dr. Rasmita Padhy

Abstract:
Pulses occupy an area of 68.32 million ha and contribute 57.51 million tonnes to the world’s food basket. Out of this, India shares about 35.2 per cent area and 27.65 percent of the global production. The percent contribution of pulses to the total food grain production in India has declined during the last three decades (Anon., 2011). Among the various pulses, black gram or urd bean (Vigna mungo [L.] Hepper) is an important grain legume with easily digestible protein and low flatulence contents. It is highly prized pulse, rich in phosphoric acid. Black gram grain contains about 25% protein, 56% carbohydrate, 2% fat, 4% minerals and 0.4%vitamins. Metal pollution is a multi elemental problem, in many cases, it is more appropriate to study the combined effect of sub toxic & toxic concentration of heavy metals. Zinc metal (Zn) is essential mineral element for plant growth but at high concentration these are highly toxic to plants. . Zinc sulfate (25-36% Zinc) is most commonly used source of zinc as plant micro nutrient. Several sources can supply Zn when needed but Zinc sulfate is usually used to supply the needed amount of Zn when dry fertilizer materials are used (in Zn deficiency in soil). Therefore, Zinc sulfate hepta hydrate (ZnSO4.7H2O) used in this study for Zn stress condition. The present work is aimed to study the effects of the heavy metal Zn on the growth of a widely cultivated crop Vigna mungo (L.) (OBG-31) Mahuri. Subsequent dilutions were made using distilled water & stock solution of 0, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, 1000 mg/L. Sterilized cotton & blotting papers were spread on the petriplates where test chemicals were taken & surface sterilized 10 healthy seeds of Vigna mungo (L.) were taken for study of germination. Growth of the seedling was measured by taking the root & shoot on the 7^th of day of germination. Lethal concentration (LC₅₀) was calculated by considering shoot emergence. Ratio of Root & Shoot lengths & their percent changes were in decreasing trend corresponding to increase in concentration of the solution. The correlation of the roots to the concentrations of the solution was significant at P≤ 0.05 level. The ration of root & shoot length increases with increase in concentrations of solution. The fresh weight and dry weight of shoot & root decreases with increase in concentrations of solution . Our result suggested that the presence of Zinc at higher concentration resulted in growth inhibition, structural damage of Vigna mungo (L.) Plant.