ISSN:0017-3134    

DOI:10.1080/00173139509429060

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

As part of an extensive study of pollen of Euphorbiaceae that combines transmission electron microscopy with scanning electron microscopy, distinctive exines are reported and documented for certain Acalyphoideae.CheilosaandNeoscortechinia, which comprise the tribe Cheiloseae, are the only Acalyphoideae with an echinate tectum, but their apertures and exine structure do not support a relationship to Oldfieldioideae. InDitaxis, one of the three mesocolpia is much smaller than the other two and the pollen can be easily distinguished from all other Euphorbiaceae. In SEM, the tectum of Pycnocoma appears almost complete, but in TEM the exine consists of irregular, mostly discrete tectal elements that narrow to points (=columellae) at the interface with the threadlike footlayer. The operculate grains ofAlchorneaandBoquilloniahave exines with a poorly differentiated double layer of columellae in the mesocolpium, but nearer the endoaperture the lower tier becomes greatly elongated and appears to rest directly on the endexine.Plukenetia polyadeniahas a complete tectum and a thick exine with a predominant infratectum of large, occasionally branched columellae that nearer the tectum are combined with densely spaced granules.Plukenetia penninerviahas a reticulate tectum of crenate muri and short, sparse columellae. The pollen diversity in Acalyphoideae suggests that the subfamily, many tribes and even genera may not be monophyletic.

ISSN:0017-3134    

DOI:10.1080/00173139509429061

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Pollen grains ofVitex(Labiatae) a large pantropical genus with a few temperate species, are examined by light microscopy, SEM and TEM. All grains are elliptic and tricolpate. However, exine surface sculpture varies between taxa. Two main morphological groups are recognized: the first is tectate simple-perforate to tectate perforate-fenestrate (with perforations anastomosing); the second tectate micro-reticulate/rugulate with micro-perforations in valleys between muri (the latter form is found in Madagascar taxa which have a long corolla tube). Pollen of the commonly cultivatedVitex negundois unusual in having supra-rugulate, often collapsed grains. Polar and equatorial sizes are included and the possible taxonomic significance of the morphological differences discussed.

ISSN:0017-3134    

DOI:10.1080/00173139509429062

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The external morphology, internal structure and stainability for protein of orbicules inBetula pendulaare examined by SEM and TEM. The pollen and the orbicule walls stain moderately for protein. The protein is localized mainly at the pollen aperture, in a thin layer between the exine and the intine and in the core and on the surface of the orbicules. The nitrocellulose membrane test indicates possible allergenicity of the orbicules as well as of the pollen. Since the orbicules ofBetula pendulaare 2–4 um in diameter, they can pass through the bronchiole of the lungs and cause bronchial asthma.

ISSN:0017-3134    

DOI:10.1080/00173139509429063

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The development of microspores/pollen grains and tapetum was studied in fertileRosmarinus officinalisL. (Lamiaceae). Most parts of the cell walls of the secretory anther tapetum undergo modifications before and during meiosis: the inner tangential and radial cell walls, and often also the outer tangential and radial wall, acquire a fibrous appearance; these walls become later transformed into a thin poly-saccharidic film, which is finally dissolved after microspore mitosis. Electron opaque granules found within the fibrous/lamellated tapetal walls consist of sporopollenin-like material, but cannot be interpreted as Ubisch bodies. The middle lamella and the primary wall of the outer tangential and radial tapetal walls remain unmodified, but get covered by an electron opaque, sporopollenin-like layer. Pollenkitt is formed only by lipid droplets from the ground plasma and/or ER profiles, the plastids do not form pollenkitt precursor lipids. Tapetum maturation (“degeneration”) does not take place before late vacuolate stage.

ISSN:0017-3134    

DOI:10.1080/00173139509429064

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Pollen grains stained in a sequence of osmium (O) and thiocarbohydrazide (T) solutions (collectively known as OTOTO) appear structurally stable and undistorted in the scanning electron microscope (SEM), and usually do not require special drying. In fact, OTOTO can be regarded as another special drying method in palynology. This sequential incubation also strikingly increases the electrical conductivity of pollen grains in the SEM. Compared to standard sputter-coating or vacuum evaporative procedures, OTOTO reduces charging and yields secondary electron images with significantly higher resolution.

ISSN:0017-3134    

DOI:10.1080/00173139509429065

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new method has been developed to elucidate pollen wall architecture by the separation of wall layers and the use of scanning electron microscopy (SEM). Separation of wall layers at natural boundaries, breakage across the wall and metal-coating of the specimen have been achieved by controlled ramming of free scattered ions produced by a novel “ion separating and coating – model A” instrument. The stripping treatment reveals interfaces and cross profiles of pollen walls and the sputtering treatment results in metal coating for examination with SEM. An advantage of the method is that it provides intact interfaces that are not eroded or damaged. The application of the method is exemplified by SEM analyses of pollen grains ofGossypium hirsutumL.,Zea maysL.,Sesamum indicumL. andBrassica napusL. var.oleifera. Interfaces between the tectum, column, foot, nexine-2 and intine layers of the pollen wall were all portrayed in G.hirsutumand to a great part in the other species. InG. hirsutum, it was possible to document the attachment point of surface spines, the appearance of individual baculae and the irregular labrum-operculum but regular inner labrum-aperture structure. No tectum was found inS. indicum. In all four species it was not possible to separate the intine from the sporoplast. The numbers of apertures were 20, 1, 10–14 and 3 inG. hirsutum, Z. mays, S. indicumandB. napus, respectively. The dumbell-shaped arrangement of apertures inG. hirsutum, the gear-shaped oblate sporoplast ofS. indicumand the abundance of micropores on the intine ofB. napusare characteristic features.

ISSN:0017-3134    

DOI:10.1080/00173139509429066

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Studies on pollen phenolic compounds and isozyme profiles of twelve species ofIpomoeato trace the linkage and homology between the species, through UPGMA method, revealed two broad clusters or groups. The trend of clustering and species composition of each group for both the parameters were close to each other and almost in accordance with phylogenetic interpretation with minor variations. The variations are probably due to the fact that phenolics and isozymes are different biomolecules.

ISSN:0017-3134    

DOI:10.1080/00173139509429067

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A study was carried out to investigate the influence of atmospheric pollen and fungi in determining allergic diseases by comparing the frequency of skin reactions to air sampling data over a 6-year period.

ISSN:0017-3134    

DOI:10.1080/00173139509429068

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Aeromycoflora studies above an “Aman” variety of paddy (Oryza salivaL.) were carried out for two consecutive seasons, in 1990 and 1991, in the vicinity of Barrackpore, West Bengal, by means of the culture plate exposure technique. A more or less uniform spore concentration was observed during the early part of the vegetative stages in 1990 with an abrupt increase and peak during the maximum vegetative growth period. In 1991, a uniform spore count was found up until the flowering stages. A gradual increase in spore count after flowering was recorded in both seasons with the highest peaks during harvesting, followed by a sudden decrease after the harvest. The dominant genera isolated wereAspergillus, Currularia, CladosporiumandPenicillium. Aspergillusappeared in high concentrations from the very beginning of the crop season up to the flowering stages, with a gradual fall after flowering, whileCladosporiumshowed the reverse pattern.CurrulariaandPenicilliumoccurred regularly throughout the crop season.

ISSN:0017-3134    

DOI:10.1080/00173139509429069

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor