Báo cáo lâm nghiệp: Sexual reproduction in Populus II. Information molecules of the pollen grain

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Báo cáo lâm nghiệp: "Sexual reproduction in Populus II. Information molecules of the pollen grain"Sexual reproduction in Populus II.Information molecules of the pollen grain M. Villar C. Kerhoas 2M. 1 Gaget 1 C. Dumasl Laboratoire de Reconnaissance Cellulaire et Amélioration des Plantes INRA 23879, Universit!tyon /, 43, bd 11-novembre-19i8, F-69622 Villeurbanne Cedex, and1NRA,2 Station dAmelioration des Arbres Forestiers, Ardon, F-45160 Olivet FranceIntroduction Materials and Methods P. nigra, P. deltoides and P. alba branches wereSexual interactions in flowering plants obtained from the INRA Forestry Station independ upon pollen-pistil biocommunica- Orl6ans (France). Pollen was collected andtions, involving biochemical signals ex- stored in closed vials at -18°C.changed between the mating partners. For cytochemistry, ultrathin pollen sections prepared according to Gaget (1988). They wereSuch components involved in self-incom- stained with acetate/lead citrate uranyl werepatibility are known to be the primary pro- (Reynolds, 1963), and observed at 80 kV withducts of the S (self-incompatibility) gene. the Hitachi HU 12A microscope at CMEABG, of protein and glycoprotein na-They University of Lyon, France. are (Nasrallah and Nasrallah, 1986;ture Freeze-fracture was performed according to Kerhoas et al. {1987) and replicas were obser-Gaude and Dumas, 1987). On the other ved by transmission electron microscopyhand, no data are available on the pollinic (TEM).signals implicated in interspecific incom- Pollen prints were obtained by placing pollenpatibility of self-compatible species. grains onto a formvar-coated grid for 30 min in humid Petri dishes. Grids were then stained Cellular localization and biochemical (uranyl acetate/lead citrate; Reynolds, 1963)identification of pollinic molecules, likely to and observed by TEM.be implicated in interspecific incompatibili- Biochemical analysis: pollen diffusates werety in Poplars, are presented in this paper. obtained by putting pollen grains in Tris bufferOur model involves 2 species of section (pH 7.5, 25 mM) for 10 min at 4°C. After centri- fugation, the supernatant was filtered andAigeiros (Populus nigra, P. deltoides) and concentrated by acetone precipitation. Theone species of section Leuce (P. alba). resuspended extracts were assayed for totalCrosses between species of these 2 bo- proteins, according to Bradford (1976), withtanical sections are strictly incompatible. bovine serum albumin as a standard. Samplescontaining 10 0 pg of protein were loaded on an amount of osmiophilic components in theSOS-gel, according to Laemmli’s procedure pollen coat is observed within the arcades(Laemmli, 1970). After running, proteins were of the exine (Fig. 2). These componentsstained with silver nitrate (Morrissey, 1981). also reactive in the polysaccharide wereProteins were electrophoretically transferred and glycoconjugate detection test (Gaget,onto a nitrocellulose sheet (Towbin et al., 1979)and the glycoproteins revealed by the Con 1988). These components are able to dif-A-peroxidase method (Hawkes, 1982). fuse rapidly from the pollen grain, as shown by pollen prints (not illustrated). Such diffusible materials are of polysac-Results and Discussion charidic nature and contain glycoconju- gates ...