抄録
The authors compared the uptake of Ca45 in the bodies of youg pearl oyster, Pinctada martensii (DUNKER), from filtered and unfiltered (ppt. volume of plankton and other floating materials was 2.6 c.c. /l.) sea water, to each of which Ca45 had been added to show the radioactivity of 4000 cpm/c.c..
After the radioactivity of the plankton reached maximum (Fig. 1), pearl oysters were put in to each group of the sea water and reared for periods from 2 to 72hours. Radioactivity in the mantle, gill, other organs and shell are shown in Table 1 and Figures 2 to 5. Larger amount of Ca45 was incorporated in the oysters reared in the plankton sea water than in those reared in the filtered one. The difference was larger in the mantle than in the gill. By those results gills are considered as the principal organ for the uptake of Ca from sea water, and Ca taken up from plankton through digestive organs seem to be transported to gills in low degree. The amount of Ca45 deposited in the shell reared in the plankton sea water was twice as those in the filtered one, despite that the activity of Ca45 in the plankton was one-hundredth of that of the sea water. That means that Ca are taken up by the oyster in much higher degree from plankton or other floating materials than from sea water.
