Long-term Partitioning, Storage and Remobilization of 14C Assimilated by Trifolium repens (cv. Blanca)

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Abstract
The fourth fully expanded leaf on the main stolon of white clover plants was exposed to 14CO2. Thereafter, quantitative and fractional analysis of the partitioning, storage and remobilization after defoliation of the 14C labelled assimilate was sequentially conducted over a 2- to 3-week period. In undefoliated plants, most 14C reached its final destination within 24 h of feeding. Forty percent of assimilated 14C was lost through respiration, while the rest was exported, predominantly to meristems, but also to roots, stolons and leaves. The 14C initially translocated to meristems was subsequently recovered in stolon and leaf tissue as the plants matured. Approximately 10% of assimilated 14C was invested into long-term storage in roots and stolons. These reserves were remobilized after both partial and total defoliation, and a portion of the remobilized 14C was incorporated into new growth, Partly defoliated plants regrew more rapidly than totally defoliated plants, but more 14C reserve depletion took place in the totally defoliated treatment. Reserve depletion took place from both stolons and roots, but stolon reserves were preferentially utilized. Both high and low molecular weight storage compounds were involved.