title: Isolation and characterization of soluble boron complexes in higher plants. The mechanism of phloem mobility of boron.
abstract: Boron (B) polyol complexes have been isolated and characterized from the phloem sap of celery (Apium graveolens L.) and the extrafloral nectar of peach (Prunus persica L.). In celery the direct analysis of untreated phloem sap by matrix-assisted laser desorption-Fourier transform mass spectrometry, with verification by high-performance liquid chromagraphy and gas chromatography-mass spectrometry, revealed that B is present in the phloem as the mannitol-B-mannitol complex. Molecular modeling further predicted that this complex is present in the 3,4 3',4' bis-mannitol configuration. In the extrafloral nectar of peach, B was present as a mixture of sorbitol-B-sorbitol, fructose-B-fructose, or sorbitol-B-fructose. To our knowledge, these findings represent the first successful isolation and characterization of soluble B complexes from higher plants and provide a mechanistic explanation for the observed phloem B mobility in these species.
authors.affiliation: Department of Pomology, University of California, Davis 95616, USA.
authors.forename: H
authors.initials: H
authors.lastname: Hu
authors.forename: S G
authors.initials: SG
authors.lastname: Penn
authors.forename: C B
authors.initials: CB
authors.lastname: Lebrilla
authors.forename: P H
authors.initials: PH
authors.lastname: Brown
mesh_terms: D001692:Biological Transport; D001896:Boron Compounds / Q000737:chemistry* / Q000378:metabolism; D003198:Computer Simulation; D008353:Mannitol / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D018520:Plant Shoots / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013816:Thermodynamics; D014675:Vegetables / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001896:Boron Compounds; D008353:Mannitol