Fig. 1

Effects of low temperature on net NO₃⁻fluxes of cucumber seedlings. The net NO₃⁻流量在根头发zone (A), and vascular bundles of the primary root (C), stem (E), petiole (G), midrib (I), lateral vein (K), and shoot tip (M). The average NO₃⁻流量在根头发zone (B), and vascular bundles of the primary root (D), stem (F), petiole (H), midrib (J), lateral vein (L), and shoot tip (N). Steady-state fluxes of NO₃⁻and NH₄⁺were examined by continuous flux recording for 10 min (n = 5). Different lower-case letters indicate a significant difference (P <0.05)