The action of nitrite on NADP reduction by intact spinach chloroplasts.

Isolated, intact spinach chloroplasts incubated in light in the presence of HCO 3 (-) and NO 2 (-) have the greater proportion of their NADP present in the reduced form. The steady state concentration of NADPH in light in these chloroplasts is significantly higher in the presence of NO2 than in its absence. These results invalidate earlier conclusions (Grant and Canvin, 1970) that NO 2 (-) inhibits photosynthesis by preventing NADP reduction.