Improved Apparatus for Radiobiological Syntheses

Abstract

After 24 hrs. in dark refrigerator a mature sweet-potato leaf is placed in a 28 x 130 mm. glass tube containing a small vial with 50 mg. of BaC14lO3 in it at the bottom. The tube is closed with a 2-stopcock standard taper glass stopper; the first stopcock is fitted externally with a bulb and internally with a fine dropper which extends into the vial. The tube is evacuated through the 2 stopcock, 0.5 ml. of 3 [image] HC1O4 is introduced into the bulb, and 1st stopcock opened to admit the acid to the carbonate. When evolution of CO2 is complete air is admitted to equalize pressure, the stopcocks are closed and the apparatus placed parallel to and 5 cm. from a 40 watt fluorescent lamp for 24 hrs. From 99.6-99.8% of the CO2 is assimilated. Upon extraction the leaf yields 26% of the assimilated activity in the starch and soluble sugar fraction, and 36%'' in the residual leaf material. The glucose extraction and crystallization procedure is described.