Influence of nitrogen to phosphorus supply ratio on growth, yield and biochemical parameters of kalonji (Nigella sativa L.)

Abstract

Kalonji (Nigella sativa L.) is an important medicinal plant, cultivated as a rabi crop in Pakistan. A hydroponic sand culture experiment was conducted to know the effect of N:P supply ratio at two N and P supply levels on kalonji. N:P ratios maintained in nutrient solution ranged from 2 to 18 at two levels of N and P designated as high and low. The plants produced more biomass and seeds with higher antioxidant activity, total phenolics and flavonoids at high N and P supply levels. Biological weight, seed weight, antioxidant activity and total phenolics were not affected by N:P supply ratio. However, high N:P supply ratios i.e. 15 and 18 reduced total flavonoids in kalonji seeds. N uptake by the plant was not influenced by N:P supply ratio however, P uptake was found maximum at ratios 6 to 9. It is concluded from the results that kalonji plants with better quality seeds can be more successfully grown if N:P supply ratio is maintained at or near 7 in the growth medium