摘要:

We have used atomic force microscopy and scanning tunnelling microscopy to extract new information about the substructure of theAlnus, Betula, Fagus, LycopodiumandRhododendronpollen grain exine. Our scans of exines using atomic force microscopy and scanning tunnelling microscopy reveal somewhat similar substructures forLycopodiumspores and pollen ofAlnus, Betula, FagusandRhododendron. They show various levels of alignment and clustering of substructure components. Except forAlnus, which showed polygonal clustering of spheroids and weak alignment, there is pronounced alignment of helical units. InBetula, Fagus, LycopodiumandRhododendronthe subunits appear to be helical or perhaps consisting of elongated spheroids, these spheroids are however arranged in a way that suggest that they are part of a helical structure. The diameter of these helical subunits range from 10–15 nm inFagus, 20–25 nm inLycopodium, 35–90 nm inRhododendronup to 70–120 nm inBetula. Our preparations graded from intact or fractured fresh pollen to pollen that was acetolyzed, chemically fixed and epoxy resin embedded. While our knowledge of the exact radial/lateral orientation of most of our scans is less than perfect there were in all cases substructures or cross connections of exine units. We found results from scanning and transmission electron microscopy to be helpful in understanding images from Atomic Force- and Scanning Tunnelling Microscopy.

ISSN:0017-3134    

DOI:10.1080/00173139609430006

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Confocal laser scanning microscopy (CLSM) was used to localize the major allergen,Bet vI in birch pollen. Pollen grains ofBelula pendulawere collected from catkins that had begun to release their pollen, freeze dried, and stored at 4°C. The pollen material was cryosectioned and stained with indirect immunofluorescence using the monoclonal antibody Bv 10. The observed localization ofBet vI was dependent on the treatment of the grains. When they had been prefixed with gaseous formaldehyde followed by acetoneBet vI was found in the cytoplasm. When the prefixation was omitted, a minor portion ofBet vI also appeared in the exine in the aperture regions. The allergen was not observed in the intine or the Zwischenkörper. Our suggestion is that the normal route for excretion ofBet vI is via the apertures on contact between pollen and the stigmatic surface of the pistil.

ISSN:0017-3134    

DOI:10.1080/00173139609430007

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

There are at present 25 species and 26 infraspecific taxa recognized in the resurrected genusBaccharoides. Of these, 17 species and 16 infraspecific taxa are new combinations made in this paper. Full descriptions of the pollen characters of the genus as well as the floral microcharacters, synonymy and distribution are provided. Remarks on diagnostic features are also given for most taxa in a taxonomic note.

ISSN:0017-3134    

DOI:10.1080/00173139609430008

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The pollen morphology of 31 species (50 accessions) ofRuelliaL. is described and illustrated, based on examination with light, scanning and transmission electron microscopy. The pollen is spherical, coarsely reticulate (except for two species which are clavate), usually 3-porate, rarely 5-porate or 3-coIporate. Pollen is a good diagnostic character forRuelliaspecies. The pollen characters are discussed with regard to species relationships and functional significance.

ISSN:0017-3134    

DOI:10.1080/00173139609430009

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The PAS reaction was used to stain total insoluble polysaccharides in pollen of two species ofPinuscollected in two different years and germinatedin vitroat different pH values. PAS-detectable polysaccharides are localized in the intine, cytoplasm and amyloplasts; PAS-undetectable (callose) in the middle of the intine, but only in the distal part of the grain. The total PAS stained polysaccharide content was quantified with a microdensitometer. Values are correlated with germination percentages and pollen tube length. The total polysaccharide content, as well as pollen tube length, varies in each species according to the year, probably due to environmental conditions. Also the various pHs deeply influence pollen germination and tube length, the lowest pH being the most unfavourable condition. At this pH (3.5) the total polysaccharide content is higher than in the control (pH 5.5): this is probably due to a lack of callose synthesis for tube wall or to a depolymerization of this polysaccharide, and a subsequent storage in a PAS-detectable form.

ISSN:0017-3134    

DOI:10.1080/00173139609430010

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

It is difficult to reliably distinguishBetulaspecies solely on pollen morphological criteria. Size differences between the pollen of differentBetulaspecies have proved to provide a basis for their separation.

ISSN:0017-3134    

DOI:10.1080/00173139609430011

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue

ISSN:0017-3134    

DOI:10.1080/00173139609430005

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor