摘要:

Pollen morphology and ultrastructure have been investigated in 20 taxa ofPhagnalonCass, and two species ofAliellaQaiser & Lack (Asteraceae), by means of light microscopy, SEM, and TEM. Measurements of the polar axis and equatorial diameter, exine thickness, spine length, and the diameter/exine thickness quotient are presented. BothPhagnalonandAliellahave a thick tectum with an outer baculate layer and an irregularly interlaced inner layer. The foot layer is thin, well distinguished and separated from the tectum by a cavea. The endexine is thick, lamellated and its proximal surface is irregular. Both the pollen morphology and ultrastructure corroborate the hypothesis thatPhagnalonandAliellabelong to the basal complex of the tribe Gnaphalieae, rather than to a more derived group of that tribe, or to the Inuleae.

ISSN:0017-3134    

DOI:10.1080/00173139509429999

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Lactoris fernandezianaPhilippi, the sole member of the primitive dicotyledonous family Lactoridaceae, occurs on Masatierra Island of the Juan Fernandez archipelago. A study of its pollen, utilizing preserved flowers, disproved conclusions, based on pollen from herbarium material, that the permanent tetrahedral pollen tetrads have large sacci (Zavada & Taylor 1986, Carlquist 1964) and are anasulcate. A small, poorly defined, aperture is formed at the distal pole of each grain, but before pollen is released, premature bulging of the pollen tube through this aperture, gives the impression of a much larger one. Exine sculpturing is scabrate to microrugulate and in equatorial view the exposed surfaces of each grain contain many folds. The tectum has minute perforations and an infratectal region of granules which are sometimes fused to form incipient columellae. Tetrads are of the calymmate type in which the ektexine is continuous across the external walls of neighbouring pollen grains, but only tenuous links occur between the internal walls. There is a poorly developed foot layer, which is absent, or has a granular appearance, in some regions. Endexine is lacking and the intine has an outer region containing tubular material.Lactorismay have the same pollinator(s) as the Juan Fernandez endemicDrimys confertifolia(family Winteraceae) as a number of permanent tetrads of this species were found on stigmas ofLactoris. The pollen morphology of Lactoridaceae underscores the isolated position of this family within Magnoliidae.

ISSN:0017-3134    

DOI:10.1080/00173139509430000

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The appearance of the pollen grains (or tetrads) of some taxa of only distantly related angiosperm families Berberidaceae (Mahonia), Bignoniaceae (Catalpa), Euphorbiaceae (Phyllanthus), Iridaceae (Irissect.Juno), Malpighiaceae (Malpighia, Banisteriopsis, Heteropteris) and Martyniaceae (Ibicella, Proboscidea) is very similar. For this pollen type we propose the term “clypeate” (= covered with shields), i.e. “pollen grains with large, isolated, polygonal or circular (s)exinous shields, separated by grooves”. Despite their similar appearance both their aperture condition and wall stratification are different.Phyllanthusxelongatusand theMalpighiaspecies investigated have (panto-) porate pollen grains, and local intine thickenings are present beneath the pores, which are located between the exine shields in a regular (Phyllanthus) or more irregular manner (Malpighia). This pantoporate condition differs markedly from the aperture condition which is present in all of the other taxa investigated and can best be described as inaperturate.

ISSN:0017-3134    

DOI:10.1080/00173139509430001

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Pollen grains of 40 Nigerian woody species which are among the ecological indicator species of forest and savanna vegetation communities are described and illustrated with both LM and SEM micrographs (37). Where appropriate, observations made here are compared with those of some earlier investigators. Eight species were di- or polymorphic with respect to aperture number. The use of SEM greatly enhanced the characterisation and interpretation of pollen morphological features, particularly where these features were indistinct or not detectable in LM. This second part of the series on the pollen flora of Nigeria, as was the first, is expected to be useful in plant taxonomy, Quaternary palaeoecology and petroleum exploration as well as in archaeological research and the honey industry.

ISSN:0017-3134    

DOI:10.1080/00173139509430002

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A model which simulates emission and dispersion of pollen of Japanese cedar (Cryptomeria japonicaD. Don) was developed in order to calculate the mesoscale distribution of airborne pollen, using AMeDAS data, vegetation maps of cedar, and pollen sampling data. The relationship between the amount of airborne pollen and various meteorological elements was investigated. Deviations in air temperature and wind speed from the mean value of the past few weeks showed the highest correlation coefficients with the amount of airborne pollen. On the basis of these relationships, a pollen emission sub-model was constructed. A pollen transport and diffusion sub-model was constructed using the diffusion theory. All calculations were made on the basis of a 10 km by 10 km grid system. The complete model which was composed of these sub-models and several sub-routines, was checked by comparison with measured pollen data. This showed that the complete model was able to simulate daily variation of airborne pollen and spatial variation with distance from pollen source during the peak period of airborne cedar pollen.

ISSN:0017-3134    

DOI:10.1080/00173139509430003

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A. Le Thomas & I. K. Ferguson (Eds). Morphologie Pollinique: Biologie, Systematique et Evolution. — Acta Botanica Gallica Vol. 141, no 2 (1994). 293 pp. Price: 190 FFR (Soc. Bot. France). Reviewed by Siwert Nilsson

ISSN:0017-3134    

DOI:10.1080/00173139509430004

出版商:Taylor & Francis Group    

年代:1995

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:10.1080/00173139509429998

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor