Abstract
Several methods for the quantitative extraction and estimation of nucleic acids were applied to the crop plants. The results obtained may be summarized as follows; 1. It is impossible to estimate RNA quantitatively with the Schmidt-Thannhauser procedure, because proteins are released into the RNA fraction during alkali digestion in spite of reducing the time of hydrolysis in 0.5 N KOH at 37°to 1 hour. For the estimation of RNA with the Schmidt-Thannhauser procedure, such impurities may be surmounted by the use of an ion-exchange chromatography. 2. A modification of the Ogur-Rosen procedure was proved to be satisfactory for the extraction and estimation of nucleic acids in the crop tissues, which was shown in Fig. 5. 3. The effect of temperature on the extraction of DNA from crop tissues with 0.5 N HClO4 was tested. Three 15 min extractions at 90°were found to give maximum yields, and estimates of DNA checked with values obtained by the modified diphenylamine procedure (by Burton), because u. v. spectra of the DNA extracts were not pure,
