摘要:

Pollen of all three genera of Madagascan Myristicaceae (MauloutchiaWarburg,BrochoneuraWarburg, andHaematodendronR. Capuron) and all species except one was studied with light, scanning electron, and transmission electron microscopy. A new term interstitium is introduced. Formal generic pollen descriptions are given for each genus. The distinctness of the frequently united generaMauloutchiaandBrochoneurais confirmed, as well as that of the recently described new genusHaematodendron. Mauloutchiahas the most primitive exine structure andBrochoneurathe most primitive sculpturing, while pollen ofHaematodendronis more advanced in both regards.Mauloutchiais extremely eurypalynous, particularly with regard to exine structure and sculpturing, and to a lesser extent aperture type and pollen size. Stages in the evolution of columellae from a primitively columellaless condition can be observed within the pollen of the putatively primitive genusMauloutchia.

ISSN:0017-3134    

DOI:10.1080/00173138109436731

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A survey of pollen mitosis within permanent pollen tetrads of the primitive ranalean family Winteraceae revealed that two types of division, synchronous and asynchronous, are present. In the synchronous type, all four pollen grains are at exactly the same stage of division during formation of generative and vegetative (tube) nuclei and comparatively large cytoplasmic connections link the members of a tetrad. In the asynchronous type, all four pollen grains are not at exactly the same stage of nuclear division and cytoplasmic connections are absent between members of a tetrad. Each type is restricted to a particular taxon, but many species of Winteraceae have yet to be examined for this feature. Asynchronous division occurs inDrimyssect. Drimys andPseudowinteraand synchronous division occurs inBelliolum, Bubbia, ExospermumandZygogynumand probably inDrimyssect. Tasmannia (syn.Tasmannia) too. There is evidence inPseudowinterathat the asynchronous type has evolved from the synchronous. The adaptive significance of the two types is not obvious.

ISSN:0017-3134    

DOI:10.1080/00173138109436732

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Scanning electron microscopy, combined with high resolution light microscopy, show thatRubus chamaemoruspollen, like that of the other species of the genusRubus, is perforate and striate with short vallae. In addition,R. chamaemourspollen has the well known echini/bacula.

ISSN:0017-3134    

DOI:10.1080/00173138109436733

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Intracellular rearrangements during the onset of pollen tube germination were studied at the ultrastructural level in germinating lily (Lilium longiflorum) pollen. Extensive changes in the endomembrane system included dispersal of the endoplasmic reticulum away from an initial peripheral position, appearance of dictyosomes, reduction in size and number of single-membrane organelles, and loss of the contents of these organelles. After appearance of dictyosomes, there was a decrease in number of cisternae per dictyosome and an association of secretory vesicles with each dictyosome. Other changes included movement of mitochondria, change in form of mitochondria, and synthesis of starch in proplastids. These organelle changes may account for the lag period which preceded pollen tube emergence and rapid tube growth.

ISSN:0017-3134    

DOI:10.1080/00173138109436734

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Noctuipollis, a new genus of Upper Cretaceous (Campanian) pollen is described from arctic Alaska. It is characterized by three non-equidimensional pairs of apertures. Surface ornamentation is variable onNoctuipollis borealissp. nov., and there is a variance in the interpretation of this ornamentation depending on whether transmitted light or SEM microscopy is used.

ISSN:0017-3134    

DOI:10.1080/00173138109436735

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The mid-Cretaceous dinoflagellate cystAngustidinium acribesDavey & Verdier gen. et comb. nov. displays several morphological features unique among fossil dinoflagellates. On the basis of specimens from northern California, the species is redescribed and is shown to have a paratabulation expressed by the formula 2pr, 5′, 3a, 7″, Xc, 5″′, 2″″; a seven-sided intercalary archeopyle (2a only); an unusually narrow, essentially four-sided first apical paraplate; and typically a small opening or an area of periphragm thickening on each of the antapical paraplates. The distinctive features of the paratabulation are hypothesized to derive from a conventional peridiniacean pattern by subdivision of the mid-dorsal apical paraplate and by ventral shift in the right lateral limit of the first apical paraplate. The pattern is closely similar to the tabulation in living species ofHeterocapsa, notablyH. niei(Loeblich). suggesting affinity with that genus of the Peridiniaceae, rather than toPeridiniumorProtoperidiniumto whcih most fossil peridinoid cysts appear closely allied.

ISSN:0017-3134    

DOI:10.1080/00173138109436736

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This study was carried out in Jyväskylä and Turku, in central and southern Finland, with Burkard spore traps. The average diurnal variation of all non-arboreal pollen types found in sufficient quantities is presented. A high concentration ofArtemisiapollen lasting 4–8 hours was found mainly in the morning. The highest concentrations of Brassicaceae,Calluna, Cyperaceae and Rosaceae occurred during the daylight hours, often with no definite peaks. The peak occurrence of Chenopodiaceae, Compositae andPlantagopollen was around 12.00 and ofRumexfrom 06.00 to 10.00. The diurnal variation of Poaceae pollen varies considerably depending on the species flowering at the time. Peaks occurred mostly in the morning or in the afternoon. The high occurrence period forUrticapollen was during the midday and in the afternoon.

ISSN:0017-3134    

DOI:10.1080/00173138109436737

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A survey of the air spora of an agricultural farm was carried out continuously from 8 January 1978 till 8 April 1978 with Burkard automatic volumetric spore trap. Twenty-two types of fungal spores representing 22 genera were identified from the catches on the exposed traces. Of these, only spores belonging to 10 genera were frequently recorded. The circadian periodicity and percentage contribution of these ten genera are described in detail.Cladosporiumwas found to be predominant in the air and contributed 72.9% of the total air spora followed byNigrospora(7.6%).

ISSN:0017-3134    

DOI:10.1080/00173138109436738

出版商:Taylor & Francis Group    

年代:1981

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:10.1080/00173138109436730

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor