Changes in Composition of the Xylem Sap as well as in Ion Fluxes in Populus Tremula X Alba L. Xylem In Dependence on Exogenous Factors

Siebrecht, S.; Fiebelkorn, G.; Tischner, Rudolf

doi:10.1007/978-1-4020-5843-1_20

Cited by 1 publication

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“…This raises the question of the location in the control points for nitrate translocation to the shoots? As assumed by some authors, nitrate loading into xylem may be a control point involved in diurnal changes in xylem nitrate concentrations (Herdel et al, 2001; Siebrecht et al, 2007). In contrast, Delhon et al (1995b) stated that nitrate uptake is uncoupled with nitrate translocation (loading and unloading).…”

Section: Introductionmentioning

confidence: 99%

Changes in 15NO3- Availability and Transpiration Rate Are Associated With a Rapid Diurnal Adjustment of Anion Contents as Well as 15N and Water Fluxes Between the Roots and Shoots

Orieux

Demarest

Decau³

et al. 2018

Front. Plant Sci.

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Background and Aims: Understanding interactions between water and nitrate fluxes in response to nitrate availability and transpiration rate is crucial to select more efficient plants for the use of water and nitrate.Methods: Some of these interactions were investigated in intact Brassica napus plants by combining a non-destructive gravimetric device with 15NO3- labeling. The set-up allowed high-resolution measurement of the effects of a cross-combination of two concentrations of KNO3 or KCl (0.5 and 5 mM) with two different rates of transpiration controlled by the relative humidity during a day–night cycle.Key Results: Results show that (1) high external nitrate concentrations increased root water uptake significantly whatever the transpiration rate, (2) nitrate translocation depended both on the rate of nitrate uptake and loading into xylem (3) dilution-concentration effect of nitrate in the xylem was mainly modulated by both external nitrate availability and transpiration rate, (4) dynamic changes in 15N translocation in the xylem modified shoot growth and capacitance, and (5) variations in tissue concentrations of NO3- induced by the experimental conditions were balanced by changes in concentrations of chloride and sulfate ions. These effects were even more amplified under low transpiration condition and 0.5 mM external nitrate concentration.Conclusion: Taken together, these results highlight the fine and rapid adjustment of anion contents, nitrate and water flows to changes in transpiration rate and nitrate availability during a day–night cycle. The use of this non-invasive gravimetric device is therefore a powerful tool to assess candidates genes involved in nitrogen and water use efficiency.

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Section: Introductionmentioning

confidence: 99%