Search results for "Seed"
showing 10 items of 668 documents
Food Caching By Willow and Crested Tits: A Test of Scatterhoarding Models
1995
In coniferous forests of Central Finland, Willow (Parus montanus) and Crest- ed Tits (P. cristatus) store seeds in a scattered distribution within their territory during the autumn. Individuals cache and recover food items while moving together as members of mixed-species flocks. The purpose of this study was to test certain predictions of scatter- hoarding models (Stapanian and Smith 1978, Clarkson et al. 1986), which predict how the animal should hoard food items from a superabundant source to maximize the number of caches recovered. Our field experiments gave support to most of the predictions of the models. Individual tits stored seeds closer to the food source when food had been availa…
Data from: Inter-annual variation and long-term trends in proportions of resident individuals in partially migratory birds
2016
Partial migration – a part of a population migrates and another part stays resident year-round on the breeding site – is probably the most common type of migration in the animal kingdom, yet it has only lately garnered more attention. Theoretical studies indicate that in partially migratory populations, the proportion of resident individuals (PoR) should increase in high latitudes in response to the warming climate, but empirical evidence exists for few species. We provide the first comprehensive overview of the environmental factors affecting PoR and the long-term trends in PoR by studying 27 common partially migratory bird species in Finland. The annual PoR values were calculated by divid…
Rains of Solitons in a Fiber Laser
2009
We report a novel and intriguing nonlinear dynamics observed in a fiber laser cavity, in which soliton pulses are created from an extended noisy background and drift until they reach a condensed phase comprising several tens of aggregated solitons. This soliton flow can be adjusted with manual cavity tuning, and can even be triggered by the injection of an external low-power cw laser.
Density-dependent effect affecting elephant seed-dispersed tree recruitment (Irvingia gabonensis) in Congo Forest.
2012
4 pages; International audience
Does landscape diversity influence species fitness in farmland plants ?
2015
In agriculture, landscape management research has proven extremely valuable for explaining species amount, such as how species capture and utilize changed landscape resources to maintain population size and community diversity. What is surprising is the apparent lack of comparable studies on the effects of landscape properties and management on species fitness. Here, we search for "pathological" situations where landscape effects on farmland plant amount mask significantly different effects on fitness. We examined the case of 83 weed species in 256 fields distributed across the UK national scale. Whether at the local scale of the neighborhood or the larger scale of 2 km, we find landscape e…
Expression Patterns of Key Hormones Related to Pea (Pisum sativum L.) Embryo Physiological Maturity Shift in Response to Accelerated Growth Conditions
2019
Protocols have been proposed for rapid generation turnover of temperate legumes under conditions optimized for day-length, temperature, and light spectra. These conditions act to compress time to flowering and seed development across genotypes. In pea, we have previously demonstrated that embryos do not efficiently germinate without exogenous hormones until physiological maturity is reached at 18 days after pollination (DAP). Sugar metabolism and moisture content have been implicated in the modulation of embryo maturity. However, the role of hormones in regulating seed development is poorly described in legumes. To address this gap, we characterized hormonal profiles (IAA, chlorinated auxin…
Broomrape weeds. Underground mechanisms of parasitism and associated strategies for their control: a review
2016
prod 2018-285d SPE GESTAD Agrosup INRA CT?; International audience; Broomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in Mediterranean, central and eastern Europe, and Asia. Due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. Instead, broomrape are in a current state of intensification and spread due to lack of broomrape-specific control programs, unconscious introduction to new areas and may be decline of …
Introduction et dispersion d'une espèce envahissante : le cas de l'ambroisie à feuilles d'armoise (Ambrosia artemisiifolia L.) en France
2011
National audience; Ambrosia artemisiifolia L. (common ragweed) was accidentally introduced into France in the 1860s. Its single vector of introduction in Europe was red clover seeds (Trifolium pratense L.), probably coming from Pennsylvania, United States at the time. A. artemisiifolia was later introduced into France in many places and at different times. This species has no natural or effective seed dispersal mechanisms and the spread of this weed in the territory is ensured by human activities that carry the seeds and create disturbed environments favourable to its development. It is now established in the Rhone Valley and a number of different factors (cropping system evolution, climate…
How does sulfur deficiency modulate pea response to water stress? Impact on early developing and mature seeds
2018
National audience; Pea (Pisum sativum L.) produces seeds rich in proteins but yield and quality remain unstable across years due to various stresses. Sulfur (S) deficiency and water stress are two abiotic stresses that interact in the current context of climate change and low-input practices, and recent studies suggest an important role for sulfate transport and metabolism in the plant response to water stress. To investigate the interplay between sulfur nutrition and the water stress response, sulfate-deprived pea plants were subjected to a 9-days period of water stress during the early reproductive phase. While water stress did not impact seed yield, sulfur deficiency alone or combined wi…
Stock de semences versus relevé de flore : comment mesurer les évolutions de la flore adventice liées à des modifications de systèmes de culture ?
2019
Le suivi des changements de la composition adventice est une préoccupation majeure lors de la mise en place de nouveaux systèmes de culture. Il se pose toutefois des questions sur la méthodologie à mettre en place pour ce type de travail. L’étude du stock de semences qui représente en théorie la flore potentielle, semble s’imposer comme la façon la plus évidente de caractériser les communautés de mauvaises herbes. Toutefois cette méthode est lourde à mettre en place et nécessite un nombre d’échantillons important. La flore adventice d’une centaine de parcelles conduites en semis direct sous couvert a été étudiée au travers de deux méthodes : un relevé de flore réalisé au printemps et un éch…