Figure 4.

35S:GRF5 plants are more resistant to nitrogen deprivation. A, Wild-type and 35S:GRF5 plants were grown for 7 d on normal one-half-strength Murashige and Skoog medium and subsequently transferred to control medium (left) or medium completely depleted of nitrogen for 12 d (right; −NO₃/NH₄). B, Photosynthetic parameters at 300 µmol photons m⁻² s⁻¹ determined by measurements of Chla fluorescence of wild-type (WT) and 35S:GRF5 plants grown as described in A. *Significantly different from the wild type (P ≤ 0.05, Student’s t test). C, Y(II) and ETR as a function of photoactive radiation (PAR; µmol photons m⁻² s⁻¹) in wild-type and 35S:GRF5 leaves after growth on nitrogen-deprived medium. Data are means ± sd of two independent experiments.