Search results for "pollina"
showing 10 items of 160 documents
Sex-specific patterns of antagonistic and mutualistic biotic interactions in dioecious and gynodioecious plants
2013
a b s t r a c t A major transition in flowering plants has been the evolution of separate sexes from hermaphroditism via gynodioecy which is considered to be the most important route. Biotic interactions, both antagonist and mutualistic, have been proposed to influence this transition which is generally accompanied by the evolution of sexual dimorphism in secondary sexual traits. While some researchers have studied sex- specific patterns in herbivory and pollination, less attention has been paid to pathogens/parasites and a limited number of studies have revised sex-specific patterns in mycorrhizal symbiosis. In this article, we explore sex-specific interactions in dioecious and gynodioecio…
The breeding system of Fumana ericifolia: first evidence of autogamy in woody Cistaceae
2001
Fumana ericifolia belongs to the family Cistaceae, in which all perennial species previously studied have been reported to be self-incompatible and xenogamous. Here we show that F. ericifolia is self-compatible and autogamous. Its flowers last only four to eight hours and produce a small amount of pollen and ovules. Self-pollination depends on changes in the relative position of the stigma and the anthers, triggered by the abscission of the petals; this in turn causes closing of the sepals, which push the anthers onto the stigma. Pollen remains highly viable and germinable, and the stigma keeps its receptivity several hours after the loss of the petals. Hand pollination treatments revealed …
The Staminal Lever Mechanism in Salvia L. (Lamiaceae) - a Review
2003
Abstract: The genus Salvia encompasses about 900 species distributed world-wide. It is characterized by the famous staminal lever mechanism of the flower which is one of the best known examples of a nototribic pollination mechanism. We hypothesize that structure and functioning of the staminal levers play a major role as key structures in speciation. To cope with the complex evolutionary processes involved, a number of different methodological approaches are needed. The present paper summarizes the literature referring to structural and functional diversity, breeding systems, systematics and evolution in Salvia.
Functional implications of the staminal lever mechanism in Salvia cyclostegia (Lamiaceae)
2011
Flower morphology and inflorescence architecture affect pollinator foraging behaviour and thereby influence the process of pollination and the reproductive success of plants. This study explored possible ecological functions of the lever-like stamens and the floral design in Salvia cyclostegia.Flower construction was experimentally manipulated by removing either the lower lever arms or the upper fertile thecae of the two stamens from a flower. The two types of manipulated individuals were intermixed with the control ones and randomly distributed in the population.Removing the sterile lower lever arms significantly reduced handling time per flower of the main pollinator, Bombus personatus. I…
Potential impact of genetically modified Lepidoptera-resistant Brassica napus in biodiversity hotspots: Sicily as a theoretical model
2016
The general increase of the cultivation and trade of Bt transgenic plants resistant to Lepidoptera pests raises concerns regarding the conservation of animal and plant biodiversity. Demand for biofuels has increased the cultivation and importation of oilseed rape (Brassica napus L.), including transgenic lines. In environmental risk assessments (ERAs) for its potential future cultivation as well as for food and feed uses, the impact on wild Brassicaeae relatives and on non-target Lepidoptera should be assessed. Here we consider the potential exposure of butterflies as results of possible cultivation or naturalization of spilled seed in Sicily (Italy). Diurnal Lepidoptera, which are pollinat…
Du verbe instrumental dans la musique subsaharienne
2021
Sub-Saharan music results from the spoken language/instrumental language relation, directed by an oral culture. In this culture, these languages transmit ? beyond their singularities ? messages thanks to either a coded signal known by the linguistic community or previously defined among a group of individuals, or is used as a true meta-language copied on the articulated and usual language used every day. Here, an instrumental musical speech can then imitate and reproduce the tonal inflexions of the language to make its matter understandable. This fact is the natural result of a strong interaction and interrelation between the spoken language and the music as well as the conception that the …
Quantitative importance of staminodes for female reproductive success inParnassia palustrisunder contrasting environmental conditions
2003
The five sterile stamens, or staminodes, in Parnassia palustris act both as false and as true nectaries. They attract pollinators with their conspicuous, but non-rewarding tips, and also produce nectar at the base. We removed staminodes experimentally and compared pollinator visitation rate and duration and seed set in flowers with and without staminodes in two different populations. We also examined the relative importance of the staminode size to other plant traits. Finally, we bagged, emasculated, and supplementary cross-pollinated flowers to determine the pollination strategy and whether reproduction was limited by pollen availability. Flowers in both populations were highly dependent o…
Latgales tradicionālā biškopība un tās ilgtspējīga attīstība
2019
Biškopības produkti ieņem īpašu vietu pārtikas, medicīnas un kosmētikas produktu nodrošinājumā cilvēku sabiedrībai, bet papildus šiem ekosistēmu pakalpojumiem bites nodrošina – savvaļas un lauksaimniecības augu apputeksnēšanu. Bišu skaita straujā samazināšanās pasaulē mūsdienās kļuvusi par vienu no aktuālākajām vides problēmām. Latvijā līdz šim nebija veikti pētījumi par biškopības stāvokli. Bakalaura darbā apkopoti galvenie Latvijas biškopības stāvokli raksturojošie dati, aptaujas dati par biškopības produktu popularitāti iedzīvotāju vidū Rīgā. Sīkāk raksturots biškopības stāvoklis un attīstības perspektīvas Latgalē, analizētas intervijas ar biškopjiem. Pēc biškopju vērtējuma nozare Latvij…
Les produits agrochimiques agissent de manière synergique sur la mortalité des abeilles
2021
Une méta-analyse, récemment publiée dans la revue internationale Nature, confirmel’effet délétère de la combinaison pesticides-parasites-malnutrition sur les abeilles, etrévèle que l’interaction synergique entre différents produits agrochimiques a un effetdisproportionné sur la mortalité des abeilles.
Black currant project: Multidisciplinary approach to agro-ecological measures
2022
The decline of wild pollinators leads to a drastic drop in the associated ecosystem service, resulting in significant lossesin agricultural yields. The production of blackcurrant “Noir de Bourgogne” could potentially be tripled, if populationsof wild pollinators were restored. Various agroecological measures beneficial to pollinators are discussed here, as wellas ongoing experimental tests. We discuss the practical possibilities of implementing these measures by blackcurrantgrowers as well as the technical locks that still exist. The return to an agroecological equlibrium for which pollinationbecomes again a free ecosystem service for agriculture, requires the integration of multiple agroec…