摘要:

Pollen from the dioecious speciesSolanum appendiculatumH. et B. ex Dun. is dimorphic. Pollen from the functional male flowers is tricolporate and pollen from the functional female flowers is inaperturate. Pollen from both types of flowers exhibit a high percentage of viability. Ultrastructural studies of the development in both pollen types is similar except for the development of apertures. Early in development, pollen from the male flower lacks deposition of the primexine in the apertural region. Pollen from the female flowers develops a primexine in the position of the apertures similar to the primexine in non‐apertural areas. Following the development of sexine in both pollen types, the nexine is accreted on unit‐membrane like structures. After the nexine has developed, the development of the intine ensues and is completed before anthesis. In pollen from the female flowers the nexine and intine exhibit thickening in various places. These thickenings are similar to those in the apertural region of the tricolporate pollen, however, the number of thickenings and the position of the thickenings appear to be random in the inaperturate pollen. The development of tricolporate and inaperturate pollen in a single species provides insight into the control of the number, position and formation of the pollen aperture in angiosperms.

ISSN:0017-3134    

DOI:10.1080/00173139709362600

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The pollen morphology and ultrastructure ofAustromatthaea elegans, Hedycarya angustifolia, H. loxocarya, Kibara rigidifolia, Leviera acuminata, Steganthera macooraiaandTetrasynandra laxiflora, are described. All are Australian members of the Monimiaceaesensu strictoof the order Laurales, subclass Magnoliidae. Except forHedycarya angustifolia, which has pollen grains in permanent tetrads, all species have small, globose, apolar, inaperturate pollen. They can be identified under SEM by their surface ornamentation:Austromatthaeahas fossulate sculpturing;Hedycarya angustifoliahas tetrads with a warty configuration;H. loxocaryahas echinate pollen;Kibarahas spherical gemmae with nipple‐like projections;Levierahas stellate sculpturing;Stegantherahas a verrucose surface with small spherical projections on each verruca, andTetrasynandrais gemmate with one to several spiny projections on each gemma. The pollen grains of all genera of Australian Monimiaceaesensu stricto, some the results of previous studies, are summarized in tabular form. The exine has no columellae, foot layer or endexine, in contrast to the family Atherospermataceae (syn. subfamily Atherospermatoideae of the Monimiaceae,sensu lato). The most elaborate type of wall structure consists of radial elements ("radial processes") with white line‐centered regions extending from beyond the intine to the tectal region and a two‐layered intine with an outer channelled part (onciform zone). Trends of evolution from this type are discussed and comparisons are made with other Monimiaceae, Lauraceae, Amborellaceae and Trimeniaceae.

ISSN:0017-3134    

DOI:10.1080/00173139709362601

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The pollen morphology of 86 species belonging to 19 genera of the Melastomataceae in Thailand was examined by both light‐ and scanning electron microscopy. Three pollen groups and five pollen types could be established: Group 1 has one type,Pternandratype, with tricolporate pollen. Group 2 comprises two heterocolpate pollen types with subsidiary colpi, theAnerincleistusand theDiplectriatypes and Group 3 comprises two heterocolpate pollen types, theBlastusand thePachycentriatypes, with intercolpar concavities. A key for the identification of these pollen types as well as the possible phylogenetic trends is presented.

ISSN:0017-3134    

DOI:10.1080/00173139709362602

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A total of 93 honey samples were analyzed from the Los Lagos Region (provinces of Valdivia, Osorno, Llanquihué and Chiloé) in Chile, of which 47 were monofloral and the rest polyfloral. The majority of the monofloral honeys were ulmo ones (37 honeys), characterized by the presence ofEucryphia‐Lotus‐Eucalyptuspollen. Five willow honeys containingSalix‐Eucryphia‐Lotuspollen were also identified together with 3 monofloral tineo honeys, with a predominance ofWeinmannia‐Salix‐Eucryphia, a single rape honey (Brassicaspp.) and another of white clover (Trifolium repens).The polyfloral honeys contain high quantities of pollen characteristic of monofloral honeys, along with pollen of other plants (especially nectar‐producing ones). The following classification for this group of honeys is proposed: Polyfloral I and II (Eucryphiapredominant), Polyfloral III (Weinmanniapredominant), Polyfloral IV (Lotuspredominant), Polyfloral V and VI (co‐predominance of two and three taxa respectively, in different combinations).

ISSN:0017-3134    

DOI:10.1080/00173139709362603

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Aeropalynological methods are used to examine the flowering seasons of 18 different plant taxa in Budapest between 1991–1996. Start dates, end dates, length of flowering season and yearly totals of pollen grains are computed and the main characteristics of the pollen seasons are examined in relation to meteorological factors.

ISSN:0017-3134    

DOI:10.1080/00173139709362604

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An analysis of the airspora, comprising pollen and fungal spores, was conducted over a two‐year period in an industrial area near Johannesburg. The purpose of the study was to establish the atmospheric incidence, and ascertain the role of these aero‐allergens in upper respiratory tract illnesses (URI) in the area. Monitoring in the first year of the study was simply to establish incidence levels. Pollen exhibited two seasons, a short but intense spring season, during which pollen from exotic species introduced from the northern hemisphere constituted the main allergy threat, and a longer summer season during which grasses were dominant. Fungal spores showed one long season, extending from early summer to late autumn, withCladosporiumthe main allergen. In the second year two sites were monitored. Results indicated that lower airspora counts were recorded in an area considered problematical in terms of URI, while higher counts were recorded in a more salubrious area. It was concluded that factors other than the airsporaper sewere causative, and that these, most likely industrially‐related, could possibly increase the overall ill‐effects of the airspora.

ISSN:0017-3134    

DOI:10.1080/00173139709362605

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

This study examines the daily levels ofAlternariaandCladosporiumspores in the atmosphere in Palencia city (Spain) for three consecutive years 1990–92.AlternariaandCladosporiumrepresented 55% of all the identified spores. Their annual distributional pattern reached its maximum values in summer. Multiple regression analyses show thatCladosporiumspore concentrations have a positive correlation with minimum temperature, whereasAlternariaspore concentrations have a positive correlation with maximum temperature.Alternariaspore concentrations were also negatively correlated with precipitation. Duncan's multiple range test ofAlternariadata show that winds blowing from a northeasterly direction were significantly related to higher levels of these spores.

ISSN:0017-3134    

DOI:10.1080/00173139709362606

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0017-3134    

DOI:10.1080/00173139709362599

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor