摘要:

Twenty‐sixCoffeaand sixPsilanthusspecies are examined to provide a survey of the pollen morphological variation of the African Coffeeae. These observations are compared with data from literature and evaluated by numerical analysis. The latter corroborates that the two genera are distinguishable on the basis of pollen morphology.Coffeagrains are generally 3‐colporate, whilePsilanthusmostly has 4–5‐colporate grains. InCoffeamany species show a surprisingly high degree of pollen polymorphism. There is no doubt that this phenomenon is at least in part responsible for the poor taxonomic value of pollen features at the specific level, in this genus. As regardsPsilanthusour results seem to indicate pollen morphological differences between African (more narrow muri; no supratectal ornamentation) and Asian species (muri wider; supratectal granules), but this should be confirmed by investigating more species. This is in contradiction to the actual division in subg.Psilanthusand subg.Afrocoffea.

ISSN:0017-3134    

DOI:10.1080/00173139709362625

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Ultrastructural modifications of the intine and cytoplasm, during the maturation, activation and germination processes are described for several Poaceae pollen grains. Allergenic and antigenic proteins were found in the non apertural intine during the times of activation and germination, using TEM immunolabelling. This fact may be related to the function of the non apertural intine during the processes of pollen activation and pollen tube formation prior to fecundation. Changes in the granular particles of the cytoplasm are described and their role in pollen wall development is suggested. The pectic‐cellulosic and callosic layers of the pollen tube were formed on the degraded intine, and a relationship between pollen tube wall development and the substances expelled from the fibrillar particles was observed. The immunolabelling of the starch granules may be in agreement with their role in the allergenic process.

ISSN:0017-3134    

DOI:10.1080/00173139709362626

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A new technique of obtaining high resolution structural information on pollen‐connecting threads is outlined. The method employs a transmission X‐ray microscope which has a resolution down to 30 nm, which is greater than a light microscope (∼ 200 nm), but retains the simplicity of sample preparation for light microscopy. The advantage of the method is that there is no requirement for extensive sample preparation. Unlike electron microscopy preparation techniques, in X‐ray microscopy there is no need for dehydration, fixation, staining or coating, and the sample is imaged at ambient pressure. Viscin threads from 9 plant species were investigated, 7 from the family Onagraceae, and two Ericaceae. It was found that in some species, structural detail complemented previously presented scanning electron microscopy images of specimens. However, in a number of species we found contrasting structures, to previous scanning electron microscopy work. It was concluded that by using X‐ray microscopy we were able to both complement existing knowledge, and give new information, that had previously been lost during conventional sample preparation.

ISSN:0017-3134    

DOI:10.1080/00173139709362627

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The spores of six species, namelyGrimmia decipiens, G. elatior, G. funalis, G. orbicularis, G. pulvinataandG. trichophyllawere studied by means of TEM, SEM and LM. TEM is here used for the first time on spores of this genus. Ultrastructural spore features allowed a clear characterisation of all six species. In addition, we observed the ultrastructure of the spore wall to be different from the typical Bryopsida type, with a multilaminar structure of the exine, not previously reported in mosses. The possible evolutionary, ecological and taxonomical significance of the spore features are discussed.

ISSN:0017-3134    

DOI:10.1080/00173139709362628

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The aim of this work is to present the atmospheric pollen concentrations of Palencia, Spain. Data were collected for three consecutive years (1990–92). An active volumetric pollen trap, type CAP2, was used. During this time, 88 different pollen types were identified, of which 27 occured at more than 0.15% of the total pollen recorded annually. These types formed the main pollen spectrum of this sampling station. Pollen coming from herbs (Poaceae, Chenopodiaceae,PlantagoUrticaceae, etc.) was predominant (53.79%); arboreal pollen (Quercus, PopulusCupressaceae, etc.) represented 42.11%, and pollen from shrubs (Ericaceae,Sambucusetc.) only 4.10%.

ISSN:0017-3134    

DOI:10.1080/00173139709362629

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Airborne concentrations of pollen fromBetula(birch), Poaceae (grasses) andArtemisia(mugwort) are compared during a seven year period (90–96) with respect to both quantitative and seasonal aspects, at three different sampling sites, one in Estonia (Tartu) and two in Sweden (Stockholm and Roma on the island of Gotland). All three taxa occur in the region and are well‐known causes of allergic sensitisation. The annual total and peak values of birch, grass and mugwort pollen were found to be much higher in Tartu than in Stockholm and Roma. Both the birch and the grass pollen seasons ended later in Stockholm than in Roma and Tartu. The mugwort flowering season always began earlier in Stockholm than at the other sites, and more days elapsed between start day and peak day in Stockholm than in Tartu.

ISSN:0017-3134    

DOI:10.1080/00173139709362630

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Pollen allergens have been shown to occur in fine particles much smaller than pollen grains. As such allergenic particles have a high probability of entering the lower human airways, it is important to further investigate their origin and their biological and immunological properties. Accordingly, we have modified the particle collection surface of an Andersen Impactor using adhesive coated microscope slides to enable identification by high resolution microscopic analysis and immunodetection of allergenic particulates.

ISSN:0017-3134    

DOI:10.1080/00173139709362631

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0017-3134    

DOI:10.1080/00173139709362624

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor