Figure 1.

Biomass and the levels of nitrate, total amino acids, total protein, soluble sugars, and starch in the roots and shoots of Arabidopsis during N starvation. A, Biomass (circles) and the shoot-root ratio (triangles). B, Nitrate. C, Total amino acids. D, Total protein. E, Glc (circles) and Fru (triangles). F, Suc (circles) and starch (triangles). White symbols, Roots; black symbols, shoots. Arabidopsis plants were grown hydroponically for 35 d in a solution containing 6 mm NO₃⁻were then transferred to a 0 mm nitrate solution (day 0) for 10 d (under irradiation of 150 μmol photons m⁻² s⁻¹). Samples were collected at days 0, 1, 2, 4, and 10. The values are means ± se of three replicates (pooling three plants for 0, 1, and 2 d). FW, Fresh weight.