Nitrate assimilation in leaf blades of wheat of different age

Abstract

A field experiment on wheat (Triticum aestivum L.) cv. Shera grown at 120 kg N ha"' 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 ((ig/ml) and total amount (kg ha~'). The upper leaf blades were examined for their capacity to assimilate NO3". Highly significant correlation between NR (nitrate reductase) activity and NO^"^ 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.

Nitrogen-efficient rice cultivars can reduce nitrate pollution

“…However, N content of MNE cultivars did not increase significantly with the supply of 25 mM N over T2 (10 mM N). Ontogenetically, the pattern of NR activity corresponds to nitrate content, to which it is significantly correlated (Pokhriyal et al 1980;Kumar et al 1981). In the present Fig.…”