Fig. 5.

NO production of 5-week-old wild-type Arabidopsis grown for 7 d in P-deficient nutrition solutions containing NO₃ ⁻ or NH₄ ⁺ exposed to ambient CO₂ (350±50 µl l^–1) or elevated CO₂ (800±50 µl l^–1). (a) Photographs of NO production shown as green fluorescence in the root tips and root-hair region of representative roots of plants supplied with NO₃ ⁻ and exposed to ambient or elevated CO₂, and with NH₄ ⁺ exposed to ambient or elevated CO₂. Bar, 500 µm. (b) Effects of N form and CO₂ treatment on NO production expressed as relative fluorescence. NO production was visualized with DAF-FM DA dye. Data are means ±SD (n=15). Means followed by the same letter within a root segment are not significantly different at P <0.05.