Absorption of Magnesium and Chloride by Excised Corn Root
AUTOR(ES)
Maas, E. V.
RESUMO
Absorption characteristics of Mg2+ and Cl− were investigated with 5-day-old excised corn (Zea mays) roots. Uptake from both 0.5 and 10 milliequivalents per liter MgCl2 solutions occurred at steady state rates for the first 6 hours. Inhibition by dinitrophenol and low temperatures established that absorption during this period was metabolically mediated in the absence and presence of Ca2+. Absorption isotherms indicated dual mechanisms of Mg2+ and Cl− absorption from solutions above 1 milliequivalent per liter. The effect of H+ on absorption of Mg2+ and Cl− was typical of that generally reported for other plant roots and other ions. In the physiological pH range, Ca2+ greatly suppressed the rate of Mg2+ absorption but had little effect on Cl−. The influence of Ca2+ on Mg2+ appeared to be noncompetitive and independent of its effect on membrane permeability.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=365869Documentos Relacionados
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