Uptake and loss of45Ca2+,22Na+, and H232PO4-by tea pollen tubes

Abstract

Abstract Uptake and loss of 45Ca2+, 22Na+, and H2 32PO4 - by tea pollen tubes precuitured for 20 h were studied to clarify the pattern of ion uptake by pollen tubes. Uptake of 45Ca2+, 22Na+, and H2 32PO4 - which increased with the incubation time became maximum after 5, 1, and 8 h for 45Ca2+, 22Na+, and H2 32PO4 -, respectively. After the maximum uptake, the ions were excreted. The 45Ca2+ uptake was highest at pH 7.5 and the 22Na+ uptake increased as the solution pH increased up to 7.8. The H2 32PO{8in4}- uptake was greatest at pH 5.5. The uptake of 45Ca2+ and H2 32PO4 - was maximum at 25°C. The uptake of H2 32PO4 - was more affected by the temperature than that of 45Ca2+. Metabolic inhibitors [2,4-dinitrophenol (DNP), ouabain, chloramphenicol, and cycloheximide] suppressed the uptake of 45Ca2+ and H2 32PO4 -, but had no effect on the uptake of 22Na+. The 22Na+ uptake was reduced by the addition of Ca2+ but not K+. The loss of 45Ca2+ from the pollen tubes which showed three successive phases, was prevente...