Cuticular membranes (CM) were isolated enzymatically from leaves of amphibious and submerged plants, and the oxygen permeability of aerial and aquatic CMs was compared using a specially constructed oxygen electrode. Their thicknesses were estimated from transmission electron micrographs of intact leaves. When dry CMs were moistened, the permeability of typical aerial CMs changed differently from that of typical aquatic CMs during the desiccation, apparently reflecting different internal structures. The cuticle thickness was mostly < < < < 100 nm, and the range of permeance values was 5-143 ¥ ¥ ¥ ¥ 10 ----6 m s --- . The resistance of an aerial CM was always higher than that of an aquatic one from the same species. Only the aquatic CMs showed a weak proportionality between resistance and thickness. The relation between resistance and thickness varied from aquatic to aerial CMs in a species specific way.
Cuticular membranes (CMs) were isolated from leaves of amphibious and submerged plants and their CO 2 resistances were determined as a contribution to establish quantitatively the series of resistances met by CO 2 diffusing from bulk water to the chloroplasts of submerged leaves. The isolation was performed enzymatically; permeabilities were determined and converted to resistances. The range of permeance values was 3 to 43 ¥ 10 -6 m s -1 corresponding to resistance values of 23 to 295 ¥ 10 3 s m -1 , i.e. of the same order of magnitude as boundary layer resistances. The sum of boundary layer, CM, leaf cell and carboxylation resistances could be contained within the total diffusion resistance as determined from the photosynthetic CO 2 affinity of the leaf. From the same species, the aerial leaf CM resistance was always higher than the aquatic leaf CM resistance. In a terrestrial plant, the CM resistance to CO 2 diffusion was found lower in leaves developed submerged.
Producing Japanese quail were given intravenous injections of radiolanthanides as trichlorides in .03N HCl solution. In quail given 15 mumol lanthanide pr 100 g body weight, the liver accumulated 46 to 82% of the dose by 18 hr after the injection. The growing oocytes accumulated 6 to 24% of the dose. The spleen had the greatest concentration of radiolanthanide (14 to 38%/g), the liver 9 to 19%/g, and the most heavily labeled oocytes 3 to 9%/g. The atomic number of the lanthanide for the 9 lanthanides used was not a factor in these accumulations. Levels of 140La were maximal in the membranes of the growing oocytes by 6 hr (4%) and in the contents by 2 days (19%). The smaller the number of mumol the greater was the percent accumulation in the oocytes. Thus, for .015 mumol 140La/100 g, 75% was present in the oocytes by 18 hr. The most heavily labeled oocytes contained 21%/g vs. 2.9%/g for the liver and 1.3%/g for the spleen. The sum of 140La depositions in eggs laid over 8 days (11 quail, 87 eggs) was, per quail, 89.6 +/- .6% (mean +/- SE) of the injected dose. The half-time value for deposition of 140La in the growing oocytes was 1.8 hr. This value represented the rate of loss of labeled vitellogenin from the plasma as vitellogenin-derived proteins were transferred into the oocytes.
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