title: Protoxylem: the deposition of a network containing glycine-rich cell wall proteins starts in the cell corners in close association with the pectins of the middle lamella.
abstract: Antibodies were used to localise polysaccharide and protein networks in the protoxylem of etiolated soybean (Glycine max L.) hypocotyls. The deposition of glycine-rich proteins (GRPs) starts in the cell corners between protoxylem elements and xylem parenchyma cells. Finally, the GRPs form a network between two mature protoxylem elements. The network also interconnects the ring- and spiral-shaped secondary wall thickenings, as well as the thickenings with the middle lamellae of living xylem parenchyma cells. In addition to the GRP network, a polysaccharide network composed mainly of pectins is involved in the attachment of the secondary wall thickenings to the middle lamellae of xylem parenchyma cells.
authors.affiliation: Biology Department, Plant Biology, University of Fribourg, 10 Chemin du Musée, 1700 Fribourg, Switzerland. ulrich.ryser@unifr.ch
authors.forename: Ulrich
authors.initials: U
authors.lastname: Ryser
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005936:Glucans; D018546:Hypocotyl / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010368:Pectins / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D018514:Plant Structures / Q000378:metabolism* / Q000648:ultrastructure; D011134:Polysaccharides / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D013025:Glycine max / Q000378:metabolism* / Q000648:ultrastructure; D014990:Xylans
chemical_list: D005936:Glucans; D010940:Plant Proteins; D011134:Polysaccharides; D018160:Receptors, Cytoplasmic and Nuclear; D014990:Xylans; C040985:phosphatidylinositol receptors; C042491:rhamnogalacturonan I; C029353:xyloglucan; D010368:Pectins; C003181:polygalacturonic acid