Effects of sodium nitroprusside, the nitric oxide donor, on photosynthesis and ultrastructure of common flax leaf blades

Solutions of sodium nitroprusside, a nitric oxide donor, were introduced at various concentrations into common flax (Linum usitatissimum L.) shoots with the transpirational water flow. Sodium nitroprusside and nitrate were found to exert similar effects on incorporation of 14C into photosynthetic products, leaf cell ultrastructure, and the export of assimilates from leaves. The results suggest that export of assimilates from leaves might be regulated by the products of incomplete nitrate reduction and that regulation may involve the NO-signaling system.