title: Analysis of sugars in squash xylem sap.
abstract: Xylem sap contains organic and inorganic compounds that might be involved in root-to-shoot communication. To clarify the physiological functions of sugars in xylem sap, we characterized the sugar compounds of the xylem sap. The 80% ethanol-soluble fraction of xylem sap contained mainly myo-inositol and oligosaccharides. The 80% ethanol precipitate was solubilized with cyclohexanediamine tetraacetate and fractionated using anion exchange chromatography. The non-bound fraction from the anion-exchange column reacted with Yariv reagent and was rich in arabinogalactan, indicating the presence of arabinogalactan proteins (AGP). The bound fraction eluted with 50 mM ammonium formate buffer and separated using size exclusion chromatography producing the pectins rhamnogaracturonan (RG)-I and RG-II with apparent molecular masses of 15000 and 11000, respectively. These results indicate that the AGP, RG-I, borate cross-linked RG-II dimer and oligosaccharides produced by root tissues are transported to above-ground organs via xylem sap.
authors.affiliation: Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572 Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Iwai
authors.forename: Masako
authors.initials: M
authors.lastname: Usui
authors.forename: Haruko
authors.initials: H
authors.lastname: Hoshino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamada
authors.forename: Toshiro
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Koichi
authors.initials: K
authors.lastname: Kakegawa
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishii
authors.forename: Shinobu
authors.initials: S
authors.lastname: Satoh
mesh_terms: D050260:Carbohydrate Metabolism; D002852:Chromatography, Ion Exchange; D028464:Cucurbita / Q000166:cytology / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism; D009088:Mucoproteins / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism; D010368:Pectins / Q000378:metabolism; D010940:Plant Proteins; D018517:Plant Roots / Q000378:metabolism; D018547:Plant Stems / Q000166:cytology / Q000378:metabolism*
chemical_list: D009088:Mucoproteins; D009844:Oligosaccharides; D010940:Plant Proteins; C006619:arabinogalactan proteins; C042491:rhamnogalacturonan I; C042492:rhamnogalacturonan II; D007294:Inositol; D010368:Pectins