Deposition of ammonium and nitrate in the roots of maize seedlings supplied with different nitrogen salts
| Autor: | Arnold J. Bloom, Alison Taylor, Wendy K. Silk, L. B. Randall |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
inorganic chemicals
Nitrogen Physiology Carbohydrates chemistry.chemical_element Plant Science xylem sap Plant Roots Zea mays chemistry.chemical_compound Animal science Nitrate nitrate Xylem Ammonium Compounds Botany Ammonium Biomass osmolarity Nitrates Osmotic concentration biology organic chemicals Osmolar Concentration food and beverages Hydrogen-Ion Concentration biology.organism_classification Research Papers ammonium root apex chemistry Organ Specificity Seedlings Seedling tissue storage Shoot Salts Deposition (chemistry) Plant Shoots |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/err410 |
| Popis: | This study measured total osmolarity and concentrations of NH(4)(+), NO(3)(-), K(+), soluble carbohydrates, and organic acids in maize seminal roots as a function of distance from the apex, and NH(4)(+) and NO(3)(-) in xylem sap for plants receiving NH(4)(+) or NO(3)(-) as a sole N-source, NH(4)(+) plus NO(3)(-), or no nitrogen at all. The disparity between net deposition rates and net exogenous influx of NH(4)(+) indicated that growing cells imported NH(4)(+) from more mature tissue, whereas more mature root tissues assimilated or translocated a portion of the NH(4)(+) absorbed. Net root NO(3)(-) influx under Ca(NO(3))(2) nutrition was adequate to account for pools found in the growth zone and provided twice as much as was deposited locally throughout the non-growing tissue. In contrast, net root NO(3)(-) influx under NH(4)NO(3) was less than the local deposition rate in the growth zone, indicating that additional NO(3)(-) was imported or metabolically produced. The profile of NO(3)(-) deposition rate in the growth zone, however, was similar for the plants receiving Ca(NO(3))(2) or NH(4)NO(3). These results suggest that NO(3)(-) may serve a major role as an osmoticant for supporting root elongation in the basal part of the growth zone and maintaining root function in the young mature tissues. |
| Databáze: | OpenAIRE |
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