摘要:

In the legumes several pollen types were encountered during a survey of the Caesalpinioideae that were previously unknown or poorly known for the subfamily: Viscin threads (Jacqueshuberia), periporate pollen (Hardwickia, Colophospermum), diporate pollen with a single continuous colpus (Duparquetia), tetracolporate pollen (Ceratonia), and pollen tetrads (Afzelia, Diptychandra).

ISSN:0017-3134    

DOI:10.1080/00173138009424992

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The pollinium ofCalotropis procerais developed from a group of elongated mother cells which undergo meiosis and lead to the formation of linear tetraspores, microspores and finally to a united pollen mass.

ISSN:0017-3134    

DOI:10.1080/00173138009424993

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The study of the action of M.L.O., etiologic agents of Stolbur disease, was undertaken by inoculatingVinca roseathrough grafting, when the first full-bloom flower appeared. The mature anthers were successively harvested. The mycoplasmas interfere on the different tissues of the anther far from the sieve tubes of the connective where they are located. The external and middle layers: epidermis, endothecium and mesothecium become undifferenciated, and then hyperplasied, while the internal layer, tapetum and the sporogenous cells degenerate. The different stages of the degeneration of the sporogenous cells and of the adaxial “pellicule” correlated to the evolution of the flowers at the time of inoculation of the disease are described here. Altered pollens with an hypertrophied intine, pollens reduced to their modified exine skeleton and exine residues fusing together and with the locular “pellicule” were observed successively. Finally remnants of pollen grains only exist as an interparietal sporopollenin deposit while the mesothecial cells acquire secretory properties. These results are discussed in the light of bibliographical data concerning different cases of sterility from genetic and viral origins.

ISSN:0017-3134    

DOI:10.1080/00173138009424994

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Atmospheric pollen, phenologic and meteorologic data collected during 12 intervals throughout one year in Tauber traps at different elevations allowed conclusions on vertical pollen dispersal in a mountain/valley system in the Niederhorn, Switzerland. Thus, pollen spectra at higher elevations near the timberline cannot be explained by dispersal through upslope winds but through gradient winds, i.e., winds from the general prevailing direction. The gradient wind direction lying perpendicular to the slope in consideration resulted in high elevation pollen spectra representing a regional aspect whereas the lower elevation spectra more or less faithfully recorded the local vegetation. High pollen numbers occur only during the respective local pollen production period. Secondary high pollen numbers related to precipitation maxima amount to about 10%, exceptionally 20% of the total annual pollen of the respective taxon. Thus, the washout of the pollen filtered in the vegetation seems to be of minor importance. Pollen production decreases quantitatively with increasing elevation, even for the same taxon and apparently independent from the actual growth density. This fact, combined with the regionality of the pollen dispersal at high elevation leads to a distortion of the near timberline pollen assemblages in terms of the local vegetation represented. Thus, lowland pollen dispersal mechanism cannot be used to explain pollen dispersal mechanism in mountain/valley systems.

ISSN:0017-3134    

DOI:10.1080/00173138009424995

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The results of daily collection of atmospheric pollen grains and spores in Taipei, Taiwan during June 1974 and May 1975 are presented. A total of 26307 grains belonging to more than 62 taxa were obtained. Most were of short distance dispersion. The results show that 56% were tree pollen grains with over 38 taxa, 22.7% grass pollen grains, 10.2% fern spores with over 13 taxa, 9.1 % weed pollen grains with over 10 taxa, and 2% unidentified taxa. Of the annual count, 20.7% were collected in the summer and were dominated by fern spores. In the autumn 26.3 % were collected and were dominated by grasses. In the winter, 4.4% was collected and in the spring, 48.6% with trees dominating. The relationships between pollen occurrence and meteorological factors is also discussed.

ISSN:0017-3134    

DOI:10.1080/00173138009424996

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A plea for using the terms “sculpture” and “structure” as defined by Potonié is discussed.

ISSN:0017-3134    

DOI:10.1080/00173138009424997

出版商:Taylor & Francis Group    

年代:1980

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:10.1080/00173138009424991

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor