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The structure of perigonal nectaries, nectar production and carbohydrate composition were compared at various stages in the lifespan of the flower of Fritillaria meleagris L. The six nectaries each occupied a groove that is located 2–4 mm above the tepal base. The average nectary measured 11.0 mm long and 1.0–1.2 mm wide. The structure of nectaries situated(More)
BACKGROUND Pollination drops and nectars (floral nectars) are secretions related to plant reproduction. The pollination drop is the landing site for the majority of gymnosperm pollen, whereas nectar of angiosperm flowers represents a common nutritional resource for a large variety of pollinators. Extrafloral nectars also are known from all vascular plants,(More)
Studies on the diversity of yeasts in floral nectar were first carried out in the late 19th century. A narrow group of fermenting, osmophilous ascomycetes were regarded as exclusive specialists able to populate this unique and species poor environment. More recently, it became apparent that microorganisms might play an important role in the process of plant(More)
Plant-ant interactions are generally considered as mutualisms, with both parties gaining benefits from the association. It has recently emerged that some of these mutualistic associations have, however, evolved towards other forms of relationships and, in particular, that plants may manipulate their partner ants to make reciprocation more beneficial,(More)
A population of Buglossoides purpurocaerulea (L.) I.M. Johnst. (Boraginaceae–Lithospermeae) located in Lecceto (Siena Province, Tuscany, central Italy) has been studied to compare floral nectar attributes and forager species between sun-exposed and shaded plants. Flower anthesis and maturity of sexual organs were also investigated. Average flower anthesis(More)
Pollen hydration status at dispersal depends on many parameters and on this basis two main groups of grains may be distinguished: those with a low water content are usually named orthodox or desiccation-resistant, while those with a higher water content at dispersal are known as recalcitrant or desiccation-sensitive due to their reduced mechanisms to keep(More)
Pollen of larch (Larix × marschlinsii) and Douglas-fir (Pseudotsuga menziesii) was used in homospecific and heterospecific crosses. Germination of heterospecific pollen in ovulo was reduced in post-pollination prefertilization drops. This provides evidence of selection against foreign pollen by open-pollinated exposed ovules in these two sister taxa, which(More)
Functional pollen is needed to successfully complete fertilization. Pollen is formed inside the anthers following a specific sequence of developmental stages, from microsporocyte meiosis to pollen release, that concerns microsporocytes/microspores and anther wall tissues. The processes involved may not be synchronous within a flower, an anther, and even a(More)
Nectar is the most common floral pollinator reward. In dichogamous species, floral nectar production rates can differ between sexual phases. We studied the structure of nectaries located on the stylopodium and nectar production in protandrous umbellifer Angelica sylvestris. Our study species produced nectar in both floral sexual phases. Nectar sugar(More)
BACKGROUND AND AIMS Several members of Bromeliaceae show adaptations for hummingbird pollination in the Neotropics; however, the relationships between floral structure, nectar production, pollination and pollinators are poorly understood. The main goal of this study was to analyse the functional aspects of nectar secretion related to interaction with(More)
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