Effect of nitrogen fertilizers on yield and antioxidant enzymes of basil (ocimum basilicum L.) under water stress conditions

Abstract

Water scarcity in Iran has always been a limiting factor for crop and horticultural production. Under these conditions, the nutrient uptake and metabolism processes of plants are different and can reduce growth. To study water stress (at three levels) and six fertilizer regimes (Nitrogen fertilizer requirement by a combination of vermicompost and urea fertilizer) on the quantitative yield of experimental basil (Ocimum basilicum L.). Results showed that water deficit treatment reduced leaf chlorophyll content, leaf soluble proteins, shoot dry weight and essential oil yield. The highest concentration of total chlorophyll and leaf soluble protein was obtained in normal irrigation and fertilizer regime of 1 ton vermicompost. And water deficit stress reduced these two traits. The lowest activity of antioxidant enzymes was obtained under non-stress conditions. Increasing of water deficit stress increased the activity of these antioxidants among fertilizer treatments. The highest activity of this antioxidant was obtained in non-fertilizer treatment and by adding vermicompost fertilizer to fertilizer treatment of this antioxidant. Forks also declined. The shoot dry weight and essential oil yield decreased under water deficit stress. Increasing vermicompost share in fertilizer treatments led to increased yield. The percentage of essential oil increased with moderate irrigation and decreased again with severe irrigation. In general, the results showed that vermicompost had a positive effect on both vegetative and physiological traits of the plant.