Changes in lipids and polysaccharides during pollen ontogeny in Oenothera anthers

Abstract

Sudan B and PAS reactions were used for the histochemical detection of lipids and polysaccharides with light microscopy in semithin slides of resin-embedded Oenothera hookeri De Vries The names of De Vries were adopted in this paper as suggested by Davis (1927, 1934) and not the taxonomic names used earlier (Noher de Halac et al. 1990) as the plants used were not identical with the actual anthers at different ontogenic stages. The aim was to establish the variations that occur in both kinds of metabolic products during normal pollen development. In reproductive cells a wave of amylolysis/amylogenesis is observed simultaneously with a lipidic wave. Starch in diploid PMCs is different from starch in the haploid vegetative cell. The gametogenic cell produces neither reserve lipids nor starch. Callose is seen as brilliant white with Sudan B, but is PAS negative at the PMC stage, becoming PAS positive at the tetrad stage. The exine has interbedded lipopolysaccharidic materials. Tapetal plastids show an intense production of lipidic bodies after the vacuolated microspore stage. Lipidic pollen-kitt is present in the immature pollen grains and becomes dissolved at anthesis. Tapetal cells have no cellulosic cell walls from the PMC stage onwards, but they do have a glycocalix. These events have evolutionary significance and will be compared with male-sterile development.