The effect of imbibition and vernalization on the uptake and distribution of 32P-orthophosphate in the grains and grain parts of a spring and winter wheat

Abstract

32P-orthophosphate was taken up by both Marquis and Rideau wheat grains during imbibition at 24 °C and converted mainly into water-soluble organic phosphates and to a much smaller extent into the nucleic acid, phospholipid, and phosphoprotein components of both the whole grains and grain parts. Whereas the 32P incorporation into the nucleic acids and phospholipids of Rideau grains increased during the chilling period (0–5 weeks), the incorporation of 32P into these fractions was relatively low in Marquis grains and only slightly affected by cold treatment. The results suggest that the cold treatment results in overall stimulation of turnover or synthesis of nucleic acids, phosphoproteins, and membrane phospholipids in Rideau grains. The 32P incorporation data also indicate that the scutellum of both varieties acts as a "sink" for the phosphate metabolites from the other grain parts.