Figure 2. Uptake of N by sterile roots of wheat from a mixed N form solution.

Uptake determined by solution ¹⁴C depletion (organic N) or ¹⁵N recovery in plants (inorganic N). L-alanine •, D-alanine ○, L-trialanine ▾, NO₃ ^- □, NH₄ ⁺ ▪. Values are mean ± SEM; n = 3.