Presence of nitric oxide synthase activity in roots and nodules of Lupinus albus

FEBS Lett. 1996 Dec 2;398(2-3):159-64. doi: 10.1016/s0014-5793(96)01232-x.


NO is a widespread messenger molecule in physiology. We were interested in investigating whether an NO-generating system could be present in plants. NO and L-[14C]citrulline were synthesized by roots and nodules of Lupinus albus in an L-arginine-dependent manner. L-[14C]Citrulline production was inhibited by N(G)-monomethyl-L-arginine, a nitric oxide synthase antagonist, in a competitive way. NADPH-diaphorase activity was localized in the vascular bundles in root and nodules, and also in the nodule infected zone. This staining was significantly reduced in the presence of N(G)-monomethyl-L-arginine. These results indicate the presence of a putative nitric oxide synthase in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arginine / metabolism
  • Citrulline / metabolism
  • Enzyme Inhibitors / pharmacology
  • NADPH Dehydrogenase / metabolism
  • Nitric Oxide / biosynthesis
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / metabolism*
  • Plant Roots / enzymology*
  • Plants / enzymology*
  • Plants / microbiology
  • Rhizobiaceae / physiology
  • omega-N-Methylarginine / pharmacology


  • Enzyme Inhibitors
  • omega-N-Methylarginine
  • Citrulline
  • Nitric Oxide
  • Arginine
  • Nitric Oxide Synthase
  • NADPH Dehydrogenase