Influence of selenium on the antioxidant activity of Mas cotek (Ficus deltoidea) as affected by soil acidity and phosphorus (P) fertilization

Abstract

A glasshouse experiment was carried out to investigate the effect of selenium on the antioxidant activity of Ficus deltoidea (Mas cotek) at the selenium rates of 0, 10, 20, 40, and 50 g Se/ha in limed (2 t/ha CaCO3) and unlimed soils treated with and without phosphorus (P) fertilizer (100 kg P2O5/ha). The experimental set up was a complete randomized factorial design with four replications. Two months old seedlings were transplanted into polybags containing 10 kg soil and after 4 months the plants were harvested for selenium and antioxidant analyses. Selenium in the plant tissue was extracted using the dry ashing method and determined with the graphite furnace atomic absorption spectrophotometer. Meanwhile, for biochemical analyses, the antioxidant activity was determined by measuring the free radical scavenging effect with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) in the extract of the dried leaf sample. From this study, selenium content in Mas cotek was significantly increased with selenium application, and the highest selenium uptake was recorded when lime, P fertilizer, and 50 g Se/ha were applied. In terms of the antioxidant activity, Se, in general, augments antioxidant compound in Mas cotek leaves, and these compounds are induced more effectively by higher Se concentration in the soils. In short, for maximum antioxidant activity and Se content, without a major loss in yield, the recommended rate is 50 g Se/ha when lime and P fertilizer were applied. Key words: Soil-plant-antioxidant relationship, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), selenite (Se4+) fertilization, acid soil, liming.