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Characterization of Orthophosphate Absorption by Pea Root Protoplasts
D. D. LEFEBVRE and D. T. CLARKSON
Journal of Experimental Botany
Vol. 35, No. 158 (September 1984), pp. 1265-1276
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/23691202
Page Count: 12
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Root protoplasts were isolated from 4 d old seedlings of Pisum sativum. Viability was verified by fluorescin diacetate, direct blue and neutral red vital staining techniques. Phosphate influx of the protoplasts was similar to that of roots with respect to phase 1 affinity for orthophosphate (Km = 9.9 mmol m-3) and sensitivity to pH and metabolic inhibitors. Carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone decreased uptake to 4% of the control and diethylstilboestrol induced leakiness in the protoplasts. Influx was only slightly less than that in plasmolysed roots which in turn was 3.6 times lower than that of normal roots. Efflux from the protoplasts was high with a value of approximately 2% of the cellular phosphate content per hour. The elevated leakage indicated an essential difference between the effects of protoplast isolation on influx and efflux of phosphate.
Journal of Experimental Botany © 1984 Oxford University Press