( 31 ) p-nuclear magnetic resonance spectra of perfused maize ( zea mays l. , hybrid ww x br 38 ) root tips , obtained at 10-minute intervals over 12 hours or longer , indicate that no cytoplasmic or vacuolar ph changes occur in these cells in the presence of 25 millimolar k ( 2 ) so ( 4 ) , which induces extrusion of 4 to 5 microequivalents h ( + ) per gram per hour .
C0010834
cytoplasmic
C0007634
cells