title: Features of ionogenic group composition in polymeric matrix of lily pollen wall.
abstract: The composition of ionogenic groups and ion-exchange capacity were studied in the polymeric matrix of cell walls isolated from the pollen grain and tissues of vegetative organs (leaves and stems) of Lilium longiflorum Thunb. The ion-exchange capacity was evaluated at different pH values and ionic strength of 100 mM. In the two-layered pollen wall and the somatic cell walls four types of ionogenic groups were found: amino groups, two carboxyl groups (represented by residues of uronic and hydroxycinnamic acids), and phenolic OH-groups. The groups of all four types are present in the intine, whereas the exine contains one type of anion-exchange and two types of cation-exchange groups. The contents of each type group and their ionization constants were determined. The qualitative and quantitative compositions of structural polymers of the pollen intine and somatic cell walls are significantly different. It is suggested that hydroxycinnamic acids should be involved in cross-linking of polysaccharide chains in both the intine and somatic cell primary walls, and such cross-links play a crucial role in the structural organization and integrity of the pollen grain wall.
authors.affiliation: Department of Plant Physiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119899, Russia. meychik@mail.ru
authors.forename: N R
authors.initials: NR
authors.lastname: Meychik
authors.forename: N P
authors.initials: NP
authors.lastname: Matveyeva
authors.forename: Yu I
authors.initials: YI
authors.lastname: Nikolaeva
authors.forename: A V
authors.initials: AV
authors.lastname: Chaikova
authors.forename: I P
authors.initials: IP
authors.lastname: Yermakov
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D002473:Cell Wall / Q000737:chemistry; D003373:Coumaric Acids / Q000737:chemistry; D003432:Cross-Linking Reagents; D006863:Hydrogen-Ion Concentration; D027762:Lilium / Q000737:chemistry* / Q000648:ultrastructure; D009994:Osmolar Concentration; D011058:Pollen / Q000737:chemistry* / Q000648:ultrastructure; D011134:Polysaccharides / Q000737:chemistry
chemical_list: D001704:Biopolymers; D003373:Coumaric Acids; D003432:Cross-Linking Reagents; D011134:Polysaccharides