Nitrate assimilation in leaf blades of wheat of different age

Abstract

AbstractA field experiment on wheat (Triticum aestivum L.) ev. Shera grown at 120 kg N ha−1 was conducted. Half of the dose of fertilizer N was applied at the pre‐sowing stage and the other half when the seedlings were one month old. The leaf blades were examined for their NO3− content and NO3− assimilatory activity at various stages of growth and development. Soil nitrate level at 50 cm depth was determined throughout the wheat growing season in terms of cencentration (μg/ml) and total amount (kg ha−1). The upper leaf blades were examined for their capacity to assimilate NO3−. Highly significant correlation between NR (nitrate reductase) activity and NO3− content in the leaf blades. NR activity and soil NO3−, and between soil NO3− and leaf blade NO3− was observed. Findings on low soil NO3− status during the reproductive phase and the capacity of the upper leaf blades to assimilate additional amounts of NO3−, point to the need for developing a programme of soil fertilizer application whereby all the leaf blades can utilize the NO3− optimally and thus result in greater N harvest.