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Not AvailableIndian mustard (Brassica juncea L. cv. RH-30) was grown under different types and levels of nitrogen (N) sources, i.e. nitrate, ammonical, and nitrate plus ammonical, at 40, 80, and 120 kg ha−1 under green house conditions. The plants were salinized with 8 and 12 dSm−1 at 35 and 55 days after sowing. A progressive inhibition of the activity of enzymes of Nmetabolism, i.e., nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH), was bserved with increasing level of salinity.However, the magnitude of such reductions was lowest at the highest level of N (120 kg ha−1) as compared with the lowest level (40 kg ha−1) irrespective of N source. The activity of nitrate-assimilating enzymes (NR and NiR) was maximum with nitrate fertilizer, and minimum with the ammonical form. The alleviation of detrimental effects of salinity on NR and NiR was better with the highest level of N (120 kg ha−1) in nitrate form as compared with the lowest level of N (40 kg ha−1). In contrast, the maximum activity of ammonium-assimilating enzymes (GS, GOGAT, and GDH) was observed with the highest level of N (120 kg ha−1) and the minimum with the nitrate form of N under salinity. These results indicate that despite the high salinity, an increase in the concentration and uptake of N stimulates the activities of nitrate-assimilating enzymes (NR and NiR) as well as of the ammonia-assimilating enzymes (GS, GOGAT, and GDH).Not Availabl

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Not AvailableIndian mustard (Brassica juncea L. cv. RH-30) was grown under different types and levels of nitrogen (N) sources, i.e. nitrate, ammonical, and nitrate plus ammonical, at 40, 80, and 120 kg ha−1 under green house conditions. The plants were salinized with 8 and 12 dSm−1 at 35 and 55 days after sowing. A progressive inhibition of the activity of enzymes of Nmetabolism, i.e., nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH), was bserved with increasing level of salinity.However, the magnitude of such reductions was lowest at the highest level of N (120 kg ha−1) as compared with the lowest level (40 kg ha−1) irrespective of N source. The activity of nitrate-assimilating enzymes (NR and NiR) was maximum with nitrate fertilizer, and minimum with the ammonical form. The alleviation of detrimental effects of salinity on NR and NiR was better with the highest level of N (120 kg ha−1) in nitrate form as compared with the lowest level of N (40 kg ha−1). In contrast, the maximum activity of ammonium-assimilating enzymes (GS, GOGAT, and GDH) was observed with the highest level of N (120 kg ha−1) and the minimum with the nitrate form of N under salinity. These results indicate that despite the high salinity, an increase in the concentration and uptake of N stimulates the activities of nitrate-assimilating enzymes (NR and NiR) as well as of the ammonia-assimilating enzymes (GS, GOGAT, and GDH).Not Availabl

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Not AvailableThe interactions between salinity and different nitrogen (N) sources nitrate (NO−3), ammonium (NH+4), and NO−3 + NH+4 were investigated on Indian mustard (Brassica juncea cv. RH30). Treatments were added to observe the combined effect of two salinity levels (8 and 12 ds m−1) and three nitrogen sources (NO−3, NH+4, and NO−3 + NH+4) on different growth parameters and mineral composition in different plant parts, i.e., leaves, stem, and root. Salinity has been known to affect the uptake and assimilation of various essential nutrients required for normal growth and development. Different growth parameters, i.e., leaf area, dry weight of different plant parts, absolute growth rate (AGR), relative growth rate (RGR), and net assimilation rate (NAR) declined markedly by salinity at pre-flowering and flowering stages. All growth indices were less sensitive to salinity (12 d s m−1) with the nitrate form of nitrogen. It is pertinent mention that a high dose (120 kg ha−1) of nitrogen in ammonium form NH+4, acted synergistically with salinity in inhibiting growth. Plants fed with combined nitrogen (NO− 3 +NH+4) had an edge over individual forms in ameliorating the adverse effects of salinity on growth and yield. Under salt stress, different nutrient elements such as N, phosphorus (P), potassium (K+), and magnesium (Mg2+) were decreased in different plant parts (leaves, stem, and root). The maximum and minimum reduction was observed with ammoniacal and combined form of nitrogen, respectively, while the reverse was true of calcium (Ca2+), sodium (Na+), chloride (Cl−), and sulfate (SO2− 4 ) at harvest. Nitrogen application (120 Kg ha−1) incombined form had been found to maintain highest concentrations of N, P, Mg2+, and Ca2+ along with reduced concentrations of Na+, Cl−, and SO2− 4 . However, reverse was true with ammoniacal form of nitrogen.Not Availabl

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Not AvailableThe interaction between salinity (8 and 12 dS m–1) and three levels (40, 80 and 120 kg ha¯1) of different forms of nitrogen (NO3¯, NH4+ and NO3– + NH4+) were studied in Brassica juncea cv. RH-30. The plants were salinized with 8 and 12 dS m–1 at 35 and 55 days after sowing. The relative water content (RWC), water potential (ψw) and osmotic potential (ψs) exhibited a marked decline under salinity stress. The application of the combined form (NO3¯ + NH4 +) of nitrogen (120 kg ha¯1) considerably improved the water status and mitigated the adverse effect of salinity on growth. The salinity-induced osmotic effect led to stomatal closure and caused a substantial reduction in net photosynthetic rate (PN), stomatal conductance (gs) and transpiration rate (E) at the pre-flowering and flowering stages (45 and 65 DAS). Salinity effects were considerably moderated by additional nitrogen supply, which varied with the source of nitrogen, the level of salinity/fertilizer and the stage of plant growth. The inhibition in photosynthesis was relatively greater in ammonium-fed (NH4+) than in nitrate-fed (NO3¯) plants, while the transpiration rate was relatively lower in nitrate-fed plants grown either with or without saline water irrigation. The nitrate form of nitrogen @ 120 kg ha–1 proved best in alleviating the adverse effect of salinity on photosynthesis and transpiration at both the growth stages.Not Availabl