摘要:

Pollen morphology of 33 Eurasiatic taxa of the genusBuxuswas investigated by light and scanning electron microscope. The pollen is generally pantoporate. In comparison with the American and African sections of the genus, in which evolutionary lines from 3-colporatc to pantoporate conditions are found, the Eurasiatic species are more derived. A tendency to diminish pore size (Ø from 6.0 to 0.5–1.0 μm) as well as to increase number of apertures (from 12 up to 34) is correlated with geography, ranging from tropical SE Asia to the north and west parts of the area. Based on SEM details of exine 6 pollen types are described. Quantitative characters are listed, and LM and SEM illustrations are given. Pollen characters and evolutionary trends are discussed. Supposed evolutionary trends in pollen morphology of EurasiaticBuxusare (primitive → derived character state): Pori round → irregularly shaped, distinct → indistinct margin, large → small, few → many. Exine reticulate → reticulate-verrucoid → verrucoid-pilate. Reticulum continuous → interrupted. Surface of muri smooth → spinulate. The results confirm a close relation between the Eurasiatic sectionsBuxusandEugeniobuxusHatusima. The subsectionsSessilifloraeMathou andPedicellataeMathou of sectionBuxusare to be rejected. SE Asia is considered to be centre of diversity of the EurasiaticBuxusspecies. Beside Central America and southern Africa it is one of the evolutionary centres of the genusBuxus.

ISSN:0017-3134    

DOI:10.1080/00173139309429456

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In 31 species ofAcerdifferent deviative pollen grains with a quite regular arrangement of apertures were found. Tetrads with a different structure were also found. It was shown that no single dependence between structure of tetrad and arrangement of deviative pollen exists. Deviative pollen forms with a similar arrangement of apertures were also found in distant angiosperm families but only in those which usually have 3-colpate pollen grains.

ISSN:0017-3134    

DOI:10.1080/00173139309429457

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0017-3134    

DOI:10.1080/00173139309429458

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The appearance of the sulcus of many monocot pollen grains and the shape of the grains itself varies considerably with the respective pollen configuration (hydrodynamic state): (a) The turgescent, rounded pollen state within the not yet dehisced pollen sac, (b) the dry, contracted state after pollen sac dehiscence and during pollen transport, and (c) the expanded pollen state after (re-) hydration e.g. on the stigma. The sulcus shows diversity of characters, which can, however, be seen only in hydrated pollen. In dry state — and also after acetolysis — the sulcus is mostly furrow-like infolded, and various characters are not longer discernible. Based on investigations of fully hydrated and well prepared pollen, some sulcus forms are described; they are distinguished by their respective shape and surface conditions. In the past, these different sulcus configurations and forms were often overlooked. The sulcus forms are called types for practical purposes only, although there are overlaps between the extremes. The sulcus types may, nevertheless, be important taxonomic characters in some families.

ISSN:0017-3134    

DOI:10.1080/00173139309429459

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The pollen morphology of 8 species (TEM) and 85 species (SEM) of the tribe Diseae (Disinae, Satyriinae, Coryciinae), and its related tribe Orchideae, is described. It is shown that pollen tetrads are calymmate, but the massulae and pollinia are acalymmate. Pollen cohesion is also established by means of tectal bridges. Three layers of the pollen wall were observed: ektexine, exintine and endintine. Pollen characters were analysed using cladistic methods and assessed in relation to the present phylogeny of the group. Pollen data served to resolve taxa at the subtribal level and provided evidence of relationship for taxonomically problematic taxa. The Coryciinae sensu stricto are palynologically defined by a suite of synapomorphies, including a secondarily tectate exine structure, fasciculate massulae and elongated tetrads with linear microspore configuration. The Disinae can be weakly grouped on the basis of rugose or verrucose pollen surfaces. Results suggest thatBrownleeais incorrectly grouped in the Disinae, and thatHuttonaeais closely related to the Coryciinae sensu stricto.

ISSN:0017-3134    

DOI:10.1080/00173139309429460

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An attempt is made to forecast the start, the peak and the end of the pollen season. The cumulated activity method, a development of the temperature sum method, is used. Temperature (T) is transformed to activity (A) by the formula A = 2** ((T+g)/(10+h))-k where g, h and k are parameters (** indicates exponentiation). The method is tested using pollen and weather measurements from Stockholm for the years 1973–88. Of the eight pollen types tested, the best results are gained forUlmus, BetulaandPinus, with a prediction precision varying between three and six days. The method was less relevant forAlnusandQuercusand not satisfactory forCorylus, Poaceae andArtemisia.

ISSN:0017-3134    

DOI:10.1080/00173139309429461

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Seasonal variations in the mycoflora of outdoors air and sedimented dust were studied at Assiut (extreme-arid region) over a period of two years during January-December 1985 and 1986 (monthly two samples) using, respectively, the settle plate-method and the dilution plate-method. 108 species and 3 species varieties belonging to 37 genera were collected from the air (32 genera and 89 species + 2 varieties) and sedimented dust (33 genera and 92 species + 3 varieties) on glucose-Czapek Dox agar at 28°C. The total counts of fungi in air and sedimented dust showed seasonal fluctuations giving maxima, respectively, during April and December 1985; and February and November 1986. There were basic similarities between the mycoflora of air and sedimented dust with the most frequently genera being:Alternaria(5 species in air and dust),Aspergillus(20+2 varieties),Cochliobolus(7),Penicillium(16),Pleospora(1) andUlocladium(7). Their counts irregularly fluctuated giving peaks at various months. Of the above genera,Alternaria alternata, A. chlamydospora, A. tenuissima, Aspergillus flavus, A. flavusvar.columnaris, A. fumigatus, A. japonicus, A. niger, A. ochraceus, A. sydowii, A. terreus, Cochliobolus hawaiiensis, C. lunatus, C. spicifer, Penicillium aurantiogriseum, P. chrysogenum, P. citrinum, P. oxalicum, Pleospora herbarum, Ulocladium atrumandU. botrytiswere the most prevalent species. The best counts of these species were recorded at various months. Several fungi were more common in the atmosphere compared with sedimented dust and vice versa.

ISSN:0017-3134    

DOI:10.1080/00173139309429462

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Striking similarities and wide diversity in the phenolic compounds and isozyme profiles were recorded in the pollen grains ofPhoenix sylvestris, Areca catechuandCocos nucifera(Palmae). Morphologically, pollen grains of three species showed similar trends. The results of the chromatographic and electrophoretic studies were concordant with current systematic classification of Palmae.

ISSN:0017-3134    

DOI:10.1080/00173139309429463

出版商:Taylor & Francis Group    

年代:1993

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:10.1080/00173139309429455

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor