ISSN:0017-3134    

DOI:10.1080/00173138009424980

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

An attempt is made to investigate the formation of the exine pattern with SEM, during pollen development after release from the tetrad inHemerocallis middendorffiiTrautv. & Meyer var.esculenta(Koidz.) Ohwi. The microspore wall immediately after release from the tetrad is verrucose. It develops gradually into a reticulate structure by elongation and longitudinal division of the muri, in relation to an increase in volume of the microspore after dissociation of the tetrad.

ISSN:0017-3134    

DOI:10.1080/00173138009424981

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Pollen of 41 species representing all seven genera of the Neottieae were examined by scanning electron microscopy. Except forLecanorchis, the genera of the Neottieae constitute a natural group based on pollen morphology. Pollen occurs as single grains in the primitive species and in tetrads in the other species. Most grains are monoaperturate, porate or tenuate, and the tetrads often have irregularly shaped grains. Exine structure varies from tectate-perforate to semitectate.Lecanorchisis anomalous among the Neottieae in that it has 0–5, sunken, relatively small pores. Pollen morphology of this genus indicates that it is probably more closely related to the Gastrodieae than the Neottieae. There are at least four basic phyletic units in the Orchidaceae: the Neottioideae, Apostasioideae, Cypripedioideae, and Epidendroideae. These groups are distinguished by the presence of monads in at least their more primitive members and by their unique pollen types.

ISSN:0017-3134    

DOI:10.1080/00173138009424982

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Linum tenueDesf. andL. maritimumL. are distylous and have dimorphic pollen grains. The pollen surface exhibits nearly monomorphic processes in the short-styled plants, but strongly dimorphic processes in long-styled plants. This pattern of differences between pollen of the two forms is similar to that found in other sections of the genus.

ISSN:0017-3134    

DOI:10.1080/00173138009424983

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The effects of light (e.g. light intensity and light period) and temperature on the anthesis processes ofHolcus lanatusL.,Festuca rubraL. andPoa annuaL. were investigated under experimental conditions in climate rooms. All three grasses have a daily periodicity in their anthesis with one maximum and one minimum a day. This daily periodicity was not affected by either light or temperature factors. Each of the grass species studied have anthesis patterns based on specific characters which are not influenced by light intensity or light period. These light factors affected the three grass species only in their anther production.

ISSN:0017-3134    

DOI:10.1080/00173138009424984

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A study of the atmospheric pollen content was carried out on two series of samples collected respectively in 1973 and 1972 from the South of the Ivory Coast and from Chad respectively. The analysis revealed relatively important differences between the two regions, the first of which was in the Guinean zone and the second in the Sahelian zone. In the Guinean zone, the atmospheric pollen content, in spite of the dense vegetation, is weak and the pollen transport is negligible. In the Sahelian zone, where vegetation is sparser, the number of pollen grains in the atmosphere is more significant. In addition there is also a non-negligible number of allochtonous pollen grains brought by the wind coming from the north. The pollen grains of herbaceous plants are clearly dominant. A comparison of the results obtained at the two sites shows that rain and the degree of moisture in the air play an important part in the yield of pollen flow.

ISSN:0017-3134    

DOI:10.1080/00173138009424985

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

There have been few attempts to quantify the causes for annual variations in the frequency of pollen in the air. The amounts of pollen deposited annually in Tauber traps exposed in a mixed deciduous forest in southwestern Denmark 1967–76 were measured. The variations in the frequency of pollen from the local trees showed distinct biennial patterns. Flowering intensity in years following a year with low flowering was correlated with precipitation in April of the preceding year (negative,BetulaandAbuts) or average summer temperature also of the preceding year (QuercusandFagus). The pollen frequencies of grasses, herbaceous plants andCallunawere correlated with the precipitation of seasons that preceded the flowering. Years with very high pollen frequencies (1968 and 1969) must have been unpleasant for hay fever patients. Such severe pollen seasons can be predicted with fair accuracy.

ISSN:0017-3134    

DOI:10.1080/00173138009424986

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The effects of the widely differing weather conditions of the summers of 1977 and 1978 on the concentration of air-borne grass pollen over an area on the west coast of Ireland were investigated. The incidence of both total and grass pollen in the atmosphere was significantly lower in the 1978 season than in 1977. The difference in concentration recorded for the two seasons was attributed mainly to wind direction which in the summer of 1978 blew mostly over the sea while in the corresponding period of 1977 was predominantly overland. A correlation was also made between the recorded pollen counts for both seasons and the recorded wind velocity, rainfall and incidence of allergy resulting from grass pollen in the area.

ISSN:0017-3134    

DOI:10.1080/00173138009424987

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A microscopical honey analysis method that is being used to process honey samples from Mississippi (USA) is introduced. The method incorporates the acetolysis schedule and allows collection of quantitative and qualitative data in one procedure. Advantages and problems associated with acetolysis in processing honey samples from southeastern USA are reviewed.

ISSN:0017-3134    

DOI:10.1080/00173138009424988

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Based on atmospheric pollen surveys carried out for 2–3 years at four different ecological sampling sites, the grass pollen content in Delhi air has been reported. Two major grass pollen seasons have been recorded: (i) March-April, and (ii) August-October. Year-to-year and site-to-site variations in the frequency of grass pollen have been observed.

ISSN:0017-3134    

DOI:10.1080/00173138009424989

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor