The Effect of Calcium on the Uptake and Distribution of Sodium in Excised Barley Roots |
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Authors: | L. NEIRINCKX J. M. STASSART |
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Affiliation: | Laboratorium voor Plantenfysiologie, Vrije Universiteit Brussel, Paardenstraat 65, B-1640 Sint-Genesius-Rode, Belgium |
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Abstract: | The total uptake and relative distribution of Na+ along the root was investigated in excised barley roots (Hordeum vulgare L. cv. Union) of 6-day-old plants cultured on 0.25 mM CaSO4. One technique involved cutting the roots at harvest time after different uptake periods into different segments each 2 cm long. These segments were ashed and sodium was measured by flame photometry. For each experiment two treatments were done, one containing calcium in the uptake solution and one without calcium. A second technique involved the measurement of sodium transport, using labelled 22Na+ solution. Although no significant differences could be found between the calcium containing and the calciumless treatments at 24 h, there were clearcut differences for the first 6 to 8 h. The effect of calcium on the first stages of the sodium uptake was a large accumulation of sodium in the part close to the apex with a translocation close to nil; whereas the sodium taken up in the absence of calcium did not accumulate in such large amounts in the apex region but was immediately transported basipetally. |
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