Water permeability of chloroplast envelope membranes. In vivo measurement by saturation-transfer NMR.
In tulip tree (Liriodendron tulipifera) leaves, the proton NMR signal from chloroplast water is resolved from that of water in other leaf compartments. We used the saturation-transfer NMR method to measure the mean water molecule residence time within a chloroplast, (88 +/- 17) ms at 20 degrees C. From the measured chloroplast dimensions, we calculate an effective permeability coefficient of (9 +/- 2) X 10(-4) cm/s for the chloroplast envelope membrane. This is the first in vivo measurement of chloroplast water permeability.
D002462:Cell Membrane / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D010539:Permeability; D014867:Water / Q000378:metabolism*
D014867:Water