Iron deficiency in blackgram (Vigna mungo L.): redox status and antioxidant activity.

Plants growing in alkaline soil are prone to iron (Fe) deficiency. Under the effect of Fe deficiency, plants produce high amounts of reactive oxygen species, which are toxic to plant tissues and cellular components. Antioxidant enzymes play a crucial role in protecting plants from the deleterious effect of Fe deficiency. Blackgram is extensively grown in India preferring loamy soils with pH 6.5–7.8 leading to Fe deficiency. In the present study, antioxidant responses of two contrasting blackgram cultivars, "Sonkush SB23-5" and "Manas SB32-13", have been studied under Fe deficiency. A significant decrease in growth and biomass was observed in stressed plants as compared to control. "Sonkush" recorded higher hydrogen peroxide and malondialdehyde contents. Maximum decline in catalase, ascorbate peroxidase, guaiacol peroxidase and polyphenol peroxidase activities was recorded for "Sonkush" in leaves and roots. An increase in superoxide dismutase content was positively correlated with ferric chelate reductase and negatively with other antioxidative enzymes under Fe deficiency. The antioxidative responses as observed for both cultivars infer that a part of their tolerance against Fe deficiency is contributed by antioxidants. However, the work also holds the potential for further studies to explore the other tolerance mechanisms included against the stress. [ABSTRACT FROM AUTHOR]