Fate of nitrate during initial nitrate utilization by nitrogen‐depleted dwarf bean

Breteler, H.; Cate, Charlotte H. Hänisch ten

doi:10.1111/j.1399-3054.1980.tb03257.x

Cited by 33 publications

(18 citation statements)

References 22 publications

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“…The two N forms differed in their assimilation; 53% of the (12) and dwarf bean (5) to highs of 64 to 80% in wheat (7,17,23) and corn (16). Very little free NH4+-N accumulated in the tissues during NH4+-N uptake, consistent with results using +N barley plants (21,22).…”

Section: Discussionsupporting

confidence: 78%

“…Supporting this is considerable evidence that NO3 translocation is closely associated with current uptake (10, 25). It should be noted that fresh, intact shoots were excised at each sampling, since prolonged excision may disrupt N uptake and metabolism (5,23,25). In addition to the changes described above, the photoperiod was extended through the 16 h duration of this experiment.…”

Section: Introductionmentioning

confidence: 99%

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Uptake and Assimilation of NO₃⁻ and NH₄⁺ by Nitrogen-Deficient Perennial Ryegrass Turf

Bowman¹,

Paul²

1988

Plant Physiol.

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Assimilation of NO3-and NHI' by perennial ryegrass (Lolium perenne L.) turf, previously deprived of N for 7 days, was examined. Nitrogen uptake rate was increased up to four-to five-fold for both forms of N by N-deprivation as compared to N-sufficient controls, with the deficiencyenhanced N absorption persisting through a 48 hour uptake period.Nitrate, but not NH4R, accumulated in the roots and to a lesser degree in shoots. By 48 hours, 53% of the absorbed NO3-had been reduced, whereas 97% of the NH4 had been assimilated. During the early stages (O to 8 hours) of N03 uptake by N-deficient turf, reduction occurred primarily in the roots. Between 8 and 16 hours, however, the site of reduction shifted to the shoots. Nitrogen form did not affect partitio ing of the absorbed N between roots (40%) and shoots (60%) but did affect growth. Compared to N03-, NH.g uptake inhibited root, but not shoot, growth. Total soluble carbohydrates decreased in both roots and shoots during the uptake period, principally the result of fructan metabolism. Ammonium uptake resulted in greater total depletion of soluble carbohydrates in the root compared to N03-uptake. The data indicate that N assimilation by ryegrass turf utilizes stored sugars but is also dependent on current photosynthate.Nitrogen deficiency enhances N uptake by turfgrasses (3,4) as well as other crop plants (1,20). Periods ofN deprivation, ranging in duration from 1 to 4 weeks (3) to as short as 4 h (4), increased the uptake of both N03 -N and NH4+-N by mature perennial ryegrass turf. Nitrogen equivalent to a normal 50 kg N ha-' application (approximately 1 lb N/1000 ft2) was absorbed in 2 d or less (3), and it was suggested that such rapid N absorption might be the principal cause of the short-lived growth response typically observed with turf following application of inorganic N fertilizers. Implicit in this suggestion is that the absorbed N is also rapidly assimilated. The literature contains numerous reports on NO3-assimilation by N-deficient graminaceous plants (7,8,12,17,23), which describe a pattern of accumulation, reduction, and translocation. Other studies (21, 22) have revealed the dominant role of shoots in the assimilation of NO3-and roots in assimilation ofNH4'. However, there are no comparable data for mowed turf systems recovering from N deficiency.In addition to increasing N uptake, nitrogen deprivation results in accumulation of soluble carbohydrates in roots, both in perennial ryegrass (4,29) and other species (7,17,28). High levels of carbohydrates may be involved both in the uptake and assimilation ofN (1,13,17,28) (13,17,28). It is apparently not known which of the various sugars in root systems are specifically involved in assimilation, although glucose preferentially stimulated both uptake and reduction of NO3-by dwarf bean (13).This paper presents results of an investigation into the assimilation ofboth NO3-and NH4' by N-deficient perennial ryegrass turf. Whereas N assimilation has typically been studied with seedlings or excised plant ...

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Uptake and Assimilation of NO₃⁻ and NH₄⁺ by Nitrogen-Deficient Perennial Ryegrass Turf

Bowman¹,

Paul²

1988

Plant Physiol.

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“…Six h after the onset of N03 nutrition, NO3 is mainly reduced in the roots of dwarf bean (2) and the bulk of the nitrate reductase activity is also in the root system at low (0.1) or high (5 mmol dm-3) N03-concentration. Over a wide range of ambient NO3-concentrations, root NRA after 6 h was independent of the level of N03-supply (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Dwarf bean was grown for 10 d on CaCl2 solutions (0.5 mmol dm-3) to produce low-salt roots. We refer to previous papers for detailed conditions of cultivation and experimentation (2,3).…”

Section: Methodsmentioning

confidence: 99%

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Effect of Exogenous and Endogenous Nitrate Concentration on Nitrate Utilization by Dwarf Bean

Breteler¹,

Nissen²

1982

Plant Physiol.

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The effect of the exogenous and endogenous N03-concentration on net uptake, influx, and efflux of N03-and on nitrate reductase activity (NRA) in roots was studied in Phaseolus vulgars L. cv. Witte Krombek.After exposure to an Beyond 100 micromoles per cubic decimeter, root NRA was not affected by exogenous NO3-indicating that N03-uptake was not coupled to root NRA, at least not at high concentrations.Nitrate utilization in higher plants is essentially the integration of three processes: acquisition, conversion, and translocation of nitrate-nitrogen. The amount of N03-taken up by the roots represents the upper limit of a plant's N03-utilization capacity. Despite its great biological and agricultural significance, the uptake of NO3 has been studied much less extensively than the uptake ofother important ions. It is noteworthy that recent reviews on the concentration kinetics of ion transport do not give data on NO3 (14,26). Although kinetic parameters of NO3 uptake have been reviewed (7,18) sufficiently rigorous analytical procedures.In this study, several techniques were combined, e.g. measurement of net uptake, influx, and efflux of N03-and the assay of nitrate reductase activity, to construct a kinetic picture of the uptake and reduction of N03 by bean roots. Additionally, a comparison of characteristics of net N03 uptake with those of unidirectional fluxes was made and the kinetic behavior of plants during environmental depletion of NO3 was studied. Short reports of our findings have appeared (4, 5). MATERIALS AND METHODSPlant Cultivation. Phaseolus vulgaris L. cv. Witte Krombek was germinated in Perlite and transferred to N-free basal medium (3), the pH of which was kept between 4.2 and 6.5 with dilute KOH or at 5.0 ± 0.1 with a pH stat. Plants were grown for 10 d in the former and 7 d in the latter treatment. After these periods, the roots were unnodulated, the primary leaves had expanded, and the contribution of trifoliate leaves to plant weight or plant NRA2 was negligible (3). No major differences in plant weight, development, rate of N03 uptake, and NRA occurred between plants grown with manual or automatic pH control. Barley (Hordeum vulgare L. cv. Herta) was grown for 10 d with manual pH control.Nitrate utilization was initiated by adding Ca(NO3)2 to plants grown in basal medium. Germination, cultivation, and experiments were performed at 20 ± 1VC, 65 ± 10%1o RH, and a 16-h photoperiod at 30 w m-2. Dwarf bean was grown for 10 d on CaCl2 solutions (0.5 mmol dm-3) to produce low-salt roots. We refer to previous papers for detailed conditions of cultivation and experimentation (2, 3).Experiments. Net uptake of N03 and H2PO4 was assayed by following nutrient depletion in the ambient solution for several hours. In experiments with various starting concentrations, N03 was regularly replenished to the initial levels in long-term experiments, while in short-term experiments the depletion in a certain interval was plotted against the average concentration in that interval. In experiments on the time ...

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Nitrate Transport Processes and Compartmentation in Root Systems

Jackson

Volk

1981

Genetic Engineering of Symbiotic Nitrogen Fixation and Conservation of Fixed Nitrogen

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Fate of nitrate during initial nitrate utilization by nitrogen‐depleted dwarf bean

Cited by 33 publications

References 22 publications

Uptake and Assimilation of NO₃⁻ and NH₄⁺ by Nitrogen-Deficient Perennial Ryegrass Turf

Uptake and Assimilation of NO₃⁻ and NH₄⁺ by Nitrogen-Deficient Perennial Ryegrass Turf

Effect of Exogenous and Endogenous Nitrate Concentration on Nitrate Utilization by Dwarf Bean

Nitrate Transport Processes and Compartmentation in Root Systems

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Fate of nitrate during initial nitrate utilization by nitrogen‐depleted dwarf bean

Cited by 33 publications

References 22 publications

Uptake and Assimilation of NO3− and NH4+ by Nitrogen-Deficient Perennial Ryegrass Turf

Uptake and Assimilation of NO3− and NH4+ by Nitrogen-Deficient Perennial Ryegrass Turf

Effect of Exogenous and Endogenous Nitrate Concentration on Nitrate Utilization by Dwarf Bean

Nitrate Transport Processes and Compartmentation in Root Systems

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Product

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Uptake and Assimilation of NO₃⁻ and NH₄⁺ by Nitrogen-Deficient Perennial Ryegrass Turf

Uptake and Assimilation of NO₃⁻ and NH₄⁺ by Nitrogen-Deficient Perennial Ryegrass Turf