Extraction of ¹⁴C‐labeled photosynthate from aquatic plants with dimethyl sulfoxide (DMSO)1

Abstract

DMSO was tested as a solvent to extract 14 C‐labeled photosynthate from three species of aquatic plants in photosynthesis measurements and compared with the dry oxidation method for plant radioassay. Extraction of ca. 300 mg of fresh or rehydrated dry plant tissue samples in 10 ml of reagent‐grade DMSO for 8 h at 65°C resulted in a stable, nonviscous solution with excellent liquid scintillation counting characteristics. Extraction efficiency was in the range of 96–99% of fixed 14 C, and precision was comparable to, or better than, that obtained with dry oxidation. The method is simple and inexpensive, and for fresh tissue the same sample extracts can be used for chlorophyll analyses.