Partitioning, storage and remobilization of ¹⁴C assimilated by Themeda triandra Forssk¹

Abstract

The second youngest fully‐expanded leaf on the main tiller of vegetative Themeda triandra plants was exposed to ¹⁴CO₂. Thereafter, quantitative analysis of partitioning, storage and remobilization after defoliation of ¹⁴C‐labclled assimilate was conducted in serially‐harvested plants over a 27‐day period. In undefoliatcd plants, 50% of assimilated ¹⁴C was ultimately lost through respiration, while that remaining in the plant reached its final destination within two days of assimilation. A small, but significant, portion of assimilated ¹⁴C was invested into long‐term storage in roots and stem bases. These reserves were remobilized after defoliation, and a portion of the remobilized ¹⁴C was incorporated into new growth. Partially‐defoliated plants regrew more rapidly than totally‐defoliated plants, but they both made equal demands on ¹⁴C reserves. Reserve depletion took place from both roots and stem bases.