摘要:

Pollen of 20 species ofRondeletia, covering three subgenera and seven sections or “species groups” of the genus, was studied using light and scanning microscopy.Rondeletia, characterized by binucleate mature pollen grains like numerous other Rubiaceae, was found to be eurypalynous. The pollen is isopolar and small-sized (average equatorial diameters 11.4–22.8 μm) and 3-colporate (rarely 4-colporate). In equatorial view, the pollen grains are mostly ± spheroidal (rarely suboblate); in polar view (ambitus), they are mainly circular or semiangular (intersemiangular in one species only). Three different exine types are distinguishable: exine with 1) tectum minutely perforate, perforations usually isodiametric, 2) tectum with comparatively large, not isodiametric perforations or 3) coarsely reticulate; supratectal sculpturing elements are lacking; the width of the perforations and lumina is either equal or different at the apo- and mesocolpia; in a few species rod-like luminal processes are present. Palynological features of most of the investigated taxa tend to overlap so that palynology is not very helpful in supporting the subgeneric division ofRondeletia. It was, however, noted that pollen morphology, to some extent, supports the sections of subgen.Arachnothrix. Palynologically, the subgen.Rogierawas found to be heterogeneous in that each of the three investigated species is characterized by a different exine type; one of these,R. strigosa, differs from all otherRondeletiaspecies investigated in having a coarsely reticulate exine.R. odorata(subgen.Rondeletia) differs from all other investigated species in its intersemiangular pollen shape.

ISSN:0017-3134    

DOI:10.1080/00173139309428958

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The pollen of seven species ofBroussonetia(including SectionAllaeanthus) and one species ofMalasiawere examined with light, scanning and transmission electron microscopy. The pollen of all species is diporate with slightly annulate pores, and scabrate exine sculpturing. The pollen is small and all species have a columellate wall structure. The closely related genusMalasiais similar toBroussonetia. The similarity of the pollen in SectionBroussonetiaand SectionAllaeanthussuggests thatAllaeanthusbe retained in the genusBroussonetia.

ISSN:0017-3134    

DOI:10.1080/00173139309428959

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The pollen morphology of 33 species (19 genera) of Bignoniaceae native to the south Brazilian Atlantic forest was examined using light- and scanning electron microscopy. The following pollen types were established: 1. inaperturate (Adenocalymma, ClytostomaandPithecoctenium) 2. triaperturate (A) psilate (Jacaranda) (B) microreticulate (Arrabidaea, Fridericia, Lundia, Macfadyena, Melloa, Paragonia, SchlegeliaandTynnanthus) (C) reticulate (Cybistax, PyrostegiaandTabebuia), 3. stephanocolpate (Amphilophium, AnemopaegmaandUrbanolophium), 4. perisyncolpate (Mansoa).

ISSN:0017-3134    

DOI:10.1080/00173139309428960

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The aim of the present study is to describe the morphology and internal wall structure ofZingiberpollen. The pollen of 18 species ofZingiberwas examined by light, scanning and transmission electron microscopy. In the sectionsZingiberandDymczewiczia(Horan.) Benth. the pollen grains are spherical with cerebroid sculpturing while in the sectionCryptanthiumHoran. the pollen is ellipsoid with spira-striate sculpturing. All species have a thin coherent exine and an intine consisting of a thick, radially channeled outer layer and a thin, finely granular inner layer. On the basis of pollen morphology it is proposed that the sectionDymczenicziais included in the sectionZingiber. The structure of the pollen wall inZingiberresembles that ofCannaandStrelitziain having a pollen wall offering an infinite number of germination sites.

ISSN:0017-3134    

DOI:10.1080/00173139309428961

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The pollen morphology of the amphiploid speciesSonchus oleraceusL. and its putative parentsSonchus tenerrimusL. andSonchus asper(L.) Hill is investigated. The related taxaSonchus microcephalusMejías, probably derived fromS: oleraceus, is also included.S. tenerrimusandS. aspermainly show 3-zonocolporate pollen and no significant differences in size and ornamentation have been detected between them. InS. oleraceusandS. microcephalus, 3- and 4-zonocolporate pollen can be found in the same sample, in very variable proportions, depending on the population; in addition, two different size morphs have been detected in some samples ofS. oleraceus. It is proposed that the phenomenon reflects the chromosomal constitution in those species with an amphiploid origin.

ISSN:0017-3134    

DOI:10.1080/00173139309428962

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

InLiliumcv. enchantment, an orbicule peripheral sheet is characterized. It is 10 nm thick and surrounds the whole Ubisch body. Ultrastructural and cytochemical observations allow us to propose that the orbicule peripheral sheet represents remnants of a glycocalyx supported by the membrane limiting orbicule core on which sporopollenin is synthesized. A model of orbicule sporopollenin architecture and biosynthesis is discussed.

ISSN:0017-3134    

DOI:10.1080/00173139309428963

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Paleotemperatures of the last 10,000 years at 3,100 m elevation on La Malinche volcano (Mexico) were reconstructed by treating pollen analytic data by Ohngemach and Straka with numerical techniques. Pollen data from 104 modern and 97 fossil samples were analyzed in order to: (1) calibrate transfer functions linking modern pollen data to climate and vegetation data from available maps (and cross-validate the predictive model of temperature on modern data sets), and (2) reconstruct paleotemperature for the last 10,000 years from fossil pollen data. A paleotemperature curve was obtained, that ranges between 7°C in the glacial period and 12.5°C at 8,000 years BP. It matches glacial stratigraphy. Temperature is described as follows: Section S1 (from the deposit's bottom to 8,500 years BP) from 7 to 8°C. S2 from 9.0 to 11°C. S3 (around 8,000 years BP) 11.5–12.5°C. S4 from 12 to 9°C. S5 (2,700 years BP) has poor pollen concentration and estimates are unreliable. S6 from 9 to 5.5°C. S7 (around 1,550 years BP) from 6.5 to 7.5°C; S8 (ending 1.000 years BP), from 7.5 to 9.5°C and includes anthropogenic influences. S6 is given a new interpretation: open vegetation with low local pollen production and greater influence of long distance components.

ISSN:0017-3134    

DOI:10.1080/00173139309428964

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Annual variations in the ambient concentrations ofBetulapollen monitored by volumetric sampling at sites in London and also at a site to the South of the city between the years 1961–1990 are analysed in relation to the main meteorological parameters. Attention is focussed on variations in the start and duration of the seasons and on the annual patterns of pollen abundance. Consideration is given also to the variation in the severity of seasons. The paper examines possible rhythms in the annual production ofBetulapollen and develops empirical regression models from the analyses of the trends to predict the main characteristics of the seasons.

ISSN:0017-3134    

DOI:10.1080/00173139309428965

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Dyed pine pollen was released a total of 24 times from two directions outside a Scots pine seed orchard (distance between rows 7 m, that within rows between grafts 3.5 m). The distribution of pollen within the orchard was measured using 49 samplers of the rotorod type. Meteorological measurements were carried out during the experiments. The amount of pollen released was approximately 1.2*1010grains; the total caught was 39 300 grains. When the releases took place perpendicular to the rows, the pollen plume was wider and shorter than when the release was from a direction parallel with the rows. The airborne pollen concentration decreased inside the orchard at a significantly higher rate when released from a point perpendicular to the grafts than with parallel release. Almost all the pollen was caught within 30 minutes of release. The pollen was resuspended in the air in only small quantities. There are some possibilities of reducing the amount of foreign pollen from at least short distances by modifying the row structure within orchards.

ISSN:0017-3134    

DOI:10.1080/00173139309428966

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The atmospheric pollen of Durban has been monitored since 1989 using a Burkard sampler. Data are presented here for the three-year period ending in 1991. The results do not reflect the indigenous sub-tropical vegetation of the area, but rather exotic elements that are either naturalised (Morus) or cultivated (Cannabisand Poaceae). The only indigenous pollen that was recorded in any number was that of the lawn grassCynodon dactylodonand the treeCeltis africana. However, these two plant types are found country-wide, and are not restricted to sub-tropical regions. All major pollen types recorded have been implicated as allergens.

ISSN:0017-3134    

DOI:10.1080/00173139309428967

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor