Studies on the Assimilation and Translocation of ¹⁴CO₂ in Ladino Clover : II. Distribution of ¹⁴C in various fraction of assimilates in plants

Abstract

Whole plants of Ladino clover were exposed in light to ¹⁴CO₂ for 4 1/2 hours and distribution of ¹⁴C in ethanol, acid, alkali-soluble fractions and residue immediately after and 4 days after ¹⁴CO₂ treatment were investigated. Young leaves assimilate actively and retain considerable parts of their assimilates as a structural component, i.e., alkali-soluble fraction and residue (mainly protein and cellulose). The biosynthesis in these fractons seemes to be progressing rapidly, and even immediately after ¹⁴CO₂ treatment ¹⁴C was widely distributed in the structural fractions of young parts of plant. Older leaves use greater parts of their assimilates by respiration and send them to other parts of plant. therefore ¹⁴C activity decreased significantly from immediately after ¹⁴CO₂ treatment to 4 days after treatment. ¹⁴C-assimilates were translocated and accumulated as a structural or reserved fraction, namely, acid and alkali-soluble fractions and residue to young parts of stolon near growing points. ¹⁴C-assimilates in older part of stolon immediately after ¹⁴CO₂ treatment were mainly in ethanol soluble fraction. Four days after treatment ¹⁴C activity decreased significantly and ¹⁴C was distributed in reserved and structural fractions, but in small amounts. Young parts of petiole, root, lateral buds and growing points of stolon were important sink of assimilates in Ladino clover.