ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • EARTH RESOURCES AND REMOTE SENSING  (2)
  • Tristyly  (2)
  • Clonal aquatic plant  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 12 (2000), S. 203-208 
    ISSN: 1432-2145
    Schlagwort(e): Key words Tristyly ; Trimorphic incompatibility ; Pollen trimorphism ; Partial incompatibility ; Clonal aquatic plant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Eichhornia azurea (Pontederiaceae) is a mat-forming, clonal aquatic that inhabits lakes, marshes and river systems in many parts of the Neotropics. The species is tristylous with long-, mid-, and short-styled morphs commonly represented in natural populations. To investigate whether E. azurea possesses a trimorphic incompatibility system typical of tristylous species, we conducted a controlled pollination experiment on 15 clones representing the three style morphs from a natural population near Rosario, Argentina. Comparisons of fruit and seed set following self-, illegitimate, and legitimate pollinations clearly demonstrated the presence of trimorphic incompatibility in E. azurea. Self- and illegitimate pollinations produced significantly less fruit and seed than legitimate pollinations in all three style morphs. Pollen from the two anther levels within a flower exhibited contrasting compatibility relations in self-pollinations. In common with several other tristylous species in Pontederiaceae, the expression of self-incompatibility was weakest in the mid-styled morph and strongest in the short-styled morph. We discuss the ecological and evolutionary significance of the partial expression of trimorphic incompatibility in E. azurea.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 7 (1994), S. 273-281 
    ISSN: 1432-2145
    Schlagwort(e): Pollen-pistil interference ; Prior self-pollination ; Tristyly ; Self-incompatibility Stylar senescence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The potential inhibitory effects of incompatible pollen on outcrossed seed set were investigated in mass-flowering, self-incompatible, tristylous Pontederia sagittata. Prior application of self pollen, followed after 2, 4, or 6 h by compatible pollen, was conducted on five genotypes of each of the three style morphs under uniform glasshouse conditions. The greatest reductions in seed set occurred in pollinations of the long-styled (L) morph at the 6 h time interval. Smaller reductions were also found for this treatment in the mid-styled (M) morph. No significant reductions in seed set were observed in the short-styled (S) morph or in the other morphs at shorter time intervals. Observations of pollen germination and pollen tube growth indicated that the lack of inhibitory effects in the S morph may occur because relatively few pollen grains adhered to stigmas in selfpollinations. In the L and M morphs, early germination of self pollen may cause physical clogging of the stigma and style, resulting in a reduced number of compatible pollen tubes in styles. Observations of the structural integrity of styles indicated that prior germination of self pollen resulted in more rapid onset of pistil senescence, particularly in the L morph. These influences may contribute to the morph-specific differences in seed set observed following prior self-pollination of outcrossed flowers. The negative effects of incompatible pollen are likely to be most evident where ecological factors cause delays in the delivery of outcross pollen to stigmas.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 74 (1987), S. 347-351 
    ISSN: 1432-1939
    Schlagwort(e): Pontederia cordata ; Bombus ; Tristyly ; Pollination ; Behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The foraging behavior of the pollinators of tristylous Pontederia cordata was studied to determine if differences in floral morphology would lead to preferential visitation of the floral morphs. Although nectar production is not different in the three floral morphs, differences in the production and size of pollen grains produced by the three anther levels results in the morphs offering variable amounts of resources to pollen-collecting insects. Bumblebees (Bombus spp.) and the solitary bee Melissodes apicata used P. cordata primarily as a nectar source and therefore did not seem to exhibit any morph preference. In contrast, honeybees visited flowers mainly for pollen and preferred to forage on long-level anthers of the short-and mid-styled morphs. An analysis of the composition of corbicular pollen loads indicated that, relative to the frequency of production in the population: 1) honeybees collected an excess of pollen from long-level anthers; 2) bumblebees collected the three types of pollen without any apparent preference; and 3) M. apicata preferentially collected pollen from the short-level anthers — presumably because their proboscides are modified by the presence of tiny hairs. The results suggest that P. cordata in Ontario is serviced by a diverse, unspecialized pollinator fauna which is not co-adapted to the tristylous floral polymorphism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Publikationsdatum: 2019-06-27
    Beschreibung: The author has identified the following significant results. Winter and spring near-shore ice conditions were analyzed for the Beaufort Sea 1973-77, and the Chukchi Sea 1973-76. LANDSAT imagery was utilized to map major ice features related to regional ice morphology. Significant features from individual LANDSAT image maps were combined to yield regional maps of major ice ridge systems for each year of study and maps of flaw lead systems for representative seasons during each year. These regional maps were, in turn, used to prepare seasonal ice morphology maps. These maps showed, in terms of a zonal analysis, regions of statistically uniform ice behavior. The behavioral characteristics of each zone were described in terms of coastal processes and bathymetric configuration.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: E78-10136 , NASA-CR-157148
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    facet.materialart.
    Unbekannt
    In:  Other Sources
    Publikationsdatum: 2019-06-27
    Beschreibung: The growth mechanism of the grounded ice feature on Hanna's Shoal, located at approximately 162 deg W, 72 deg N in the Chukchi Sea, has been analyzed using Landsat I and II satellite imagery. The primary mechanism of growth was deduced to be the formation of large wedges of ice against the upstream edge of the feature. These wedges of piled ice form in three stages and may or may not become permanently affixed to the core of the feature. Remains of these growth patterns can sometimes be seen in the interior of the feature on the satellite imagery.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: Arctic and Alpine Research; 10; 4, 19; 1978
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...