Nitrate Uptake Rate by Soybean and Wheat Plants Determined by External Nitrate Concentration and Shoot-Mediated Demand

Saravitz, Carole H.; Devienne-Barret, Florence; Raper, C. David; Chaillou, Sylvain; Lamaze, Thierry

doi:10.1086/297551

Cited by 15 publications

(6 citation statements)

References 35 publications

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“…Previous research has demonstrated that N export from the shoot to tubers is enhanced as a result of reducing NO 3 --N supply (McDonald et al, 1996). Other studies have found that uptake of N (NO 3 -or NH 4 + ) in solution culture studies (Saravitz et al, 1998) or in the fi eld (Devienne- Barret et al, 2000) depends on N level in the nutrient solution or soil. In the present study, nitrogen (NO 3 -or NH 4 + ) was taken up rapidly by plants following replenishment rather than accumulating in the nutrient solutions (Jones, 1997).…”

Section: Resultsmentioning

confidence: 99%

Influence of Nitrogen Nutrition Management on Biomass Partitioning and Nitrogen Use Efficiency Indices in Hydroponically Grown Potato

Goins¹,

Yorio²,

Wheeler³

2004

jashs

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The National Aeronautics and Space Administration (NASA) has been conducting controlled environment research with potatoes (Solanum tuberosum L.) in recirculating nutrient film technique (NFT)-hydroponic systems as a human life support component during long-duration spaceflight. Standard nutrient solution management approaches include constant pH regulation with nitric acid (HNO3) and daily adjustment of electrical conductivity (EC) equivalent to half-strength modified Hoagland's solution, where nitrate (NO3-) is the sole nitrogen (N) source. Although tuber yields have been excellent with such an approach, N use efficiency indices are expected to be low relative to tuber biomass production. Furthermore, the high amount of N used in NFT-hydroponics, typically results in high inedible biomass, which conflicts with the need to minimize system mass, volume, and expenditure of resources for long-duration missions. More effective strategies of N fertilization need to be developed to more closely match N supply with demand of the crop. Hence, the primary objective of this study was to identify the optimal N management regime and plant N requirement to achieve high yields and to avoid inefficient use of N and excess inedible biomass production. In separate 84-day cropping experiments, three N management protocols were tested. Treatments which decreased NO3--N supply indirectly through lowering nutrient solution EC (Expt. I), or disabling pH control, and/or supplying NH4+-N (Expt. III) did not significantly benefit tuber yield, but did influence N use efficiency indices. When supplied with an external 7.5 mm NO-3--N for the first 42 days after planting (DAP), lowered to 1.0 mm NO3 -N during the final 42 days (Expt. II), plants were able to achieve yields on par with plants which received constant 7.5 mm NO3--N (control). By abruptly decreasing N supply at tuber initiation in Expt. II, less N was taken up and accumulated by plants compared to those which received high constant N (control). However, proportionately more plant accumulated N was used (N use efficiency) to produce tuber biomass when N supply was abruptly lowered at tuber initiation in Expt. II. Hence, a hydroponic nutrient solution N management system may be modified to elicit greater plant N-use while maintaining overall high tuber yield as opposed to achieving high tuber yields through excess N supply and shoot growth.

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Section: Resultsmentioning

confidence: 99%

Influence of Nitrogen Nutrition Management on Biomass Partitioning and Nitrogen Use Efficiency Indices in Hydroponically Grown Potato

Goins¹,

Yorio²,

Wheeler³

2004

jashs

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“…In general, the root nitrate reductase activity is usually lower in the region where the nitrate uptake is higher and is responsible for nitrate translocation from these root parts to the shoots [ 30 ]. While the uptake of nitrate into the root symplast depends on the concentration in the outer medium, the xylem loading process depends mainly on the shoot demand and the content of reduced N-compounds in the phloem [ 31 ]. In the present study, nitrate concentration in the xylem sap rapidly increased following anion supply (3–9 h of induction period), resulting in a higher leaf apoplastic concentration (Figure 3 ).…”

Section: Discussionmentioning

confidence: 99%

Nitrate transport in cucumber leaves is an inducible process involving an increase in plasma membrane H+-ATPase activity and abundance

et al. 2012

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BackgroundThe mechanisms by which nitrate is transported into the roots have been characterized both at physiological and molecular levels. It has been demonstrated that nitrate is taken up in an energy-dependent way by a four-component uptake machinery involving high- and low- affinity transport systems. In contrast very little is known about the physiology of nitrate transport towards different plant tissues and in particular at the leaf level.ResultsThe mechanism of nitrate uptake in leaves of cucumber (Cucumis sativus L. cv. Chinese long) plants was studied and compared with that of the root. Net nitrate uptake by roots of nitrate-depleted cucumber plants proved to be substrate-inducible and biphasic showing a saturable kinetics with a clear linear non saturable component at an anion concentration higher than 2 mM. Nitrate uptake by leaf discs of cucumber plants showed some similarities with that operating in the roots (e.g. electrogenic H+ dependence via involvement of proton pump, a certain degree of induction). However, it did not exhibit typical biphasic kinetics and was characterized by a higher Km with values out of the range usually recorded in roots of several different plant species. The quantity and activity of plasma membrane (PM) H+-ATPase of the vesicles isolated from leaf tissues of nitrate-treated plants for 12 h (peak of nitrate foliar uptake rate) increased with respect to that observed in the vesicles isolated from N-deprived control plants, thus suggesting an involvement of this enzyme in the leaf nitrate uptake process similar to that described in roots. Molecular analyses suggest the involvement of a specific isoform of PM H+-ATPase (CsHA1) and NRT2 transporter (CsNRT2) in root nitrate uptake. At the leaf level, nitrate treatment modulated the expression of CsHA2, highlighting a main putative role of this isogene in the process.ConclusionsObtained results provide for the first time evidence that a saturable and substrate-inducible nitrate uptake mechanism operates in cucumber leaves. Its activity appears to be related to that of PM H+-ATPase activity and in particular to the induction of CsHA2 isoform. However the question about the molecular entity responsible for the transport of nitrate into leaf cells therefore still remains unresolved.

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“…At low nitrate concentrations reduction occurs mainly in roots, at higher concentrations storage and then transport are adjusted to establish the N‐status ( Agrell et al 1997 ). The uptake into the root symplast from the outer medium depends on the concentration outside the root, whereas the xylem loading process depends on the shoot demand and the content of reduced N‐compounds in the phloem ( Saravitz et al 1998 ). It has been suggested that HATS is located close to the root tip whereas LATS is present in older root parts ( Rao‐Theertham et al 1997 ).…”

Section: Physiology Of Nitrate Uptakementioning

confidence: 99%

Nitrate uptake and reduction in higher and lower plants

Tischner

2000

Plant Cell & Environment

288

175

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The nitrogen compounds nitrate and ammonium are the minerals that plants need in large quantities and which limit their growth in temperate zones. The nitrate assimilation pathway starts with nitrate uptake followed by nitrate reduction resulting in ammonium which is fixed into the amino acids glutamine and glutamate in most plants. This review concentrates on nitrate uptake and nitrate reduction with respect to higher and lower plants. The physiology and the progress in molecular approaches of both processes are considered. For nitrate uptake the well‐established uptake systems are discussed and special attention is drawn to nitrate sensing and the nitrate carrier. Knowledge, particularly on nitrate sensing is rare, but it seems to be the first step in a signal transduction chain triggered by nitrate. Therefore further work should consider this topic more frequently. For nitrate reductase the focus is on the post‐translational modification as a regulatory tool for nitrate assimilation, on the intersections of carbon and nitrogen metabolism and on the molecular approaches. A few remarks on how environmental conditions affect nitrate assimilation are also included. Further progress is needed to understand the transduction of positive and negative signals from the environment affecting the expression of genes coding for the nitrate assimilating pathway.

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Nitrate Uptake Rate by Soybean and Wheat Plants Determined by External Nitrate Concentration and Shoot-Mediated Demand

Cited by 15 publications

References 35 publications

Influence of Nitrogen Nutrition Management on Biomass Partitioning and Nitrogen Use Efficiency Indices in Hydroponically Grown Potato

Influence of Nitrogen Nutrition Management on Biomass Partitioning and Nitrogen Use Efficiency Indices in Hydroponically Grown Potato

Nitrate transport in cucumber leaves is an inducible process involving an increase in plasma membrane H+-ATPase activity and abundance

Nitrate uptake and reduction in higher and lower plants

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