Search results for "Seed"

Characterisation of phenotypic plasticity in seedling stage of native and invasive populations in Ambrosia artemisiifolia L.

2012

Increased phenotypic plasticity has often been invoked as an hypothesis to explain the capacity of alien invasive plant species to colonize new environments, because it may enhance the ability of plants to cope with new biotic and abiotic conditions. Following this hypothesis, alien invasive populations should be represented by more plastic genotypes than populations in the native range. In annual species, the seedling stage is of crucial importance for population dynamics but surprisingly very few studies have investigated differences in phenotypic plasticity on seedling traits. Based on populations from the native range (North America) and the invasive range (France) of Ambrosia artemisii…

Toward a better prediction of in-field weed regulation by carabid beetles in European arable landscapes

2019

International audience; Arable agriculture is still highly reliant on herbicides to manage weeds. As part of the necessary shift towards a reduction in pesticide use, the regulatory effect of seed-eating carabid beetles on weeds has received increasing attention in agroecological research. While strong evidence points to carabids exerting a regulatory effect on certain weed species, it is difficult to predict whether a particular assemblage of carabid species will drive the function of weed seed predation in field conditions. There are also uncertainties about which key local and landscape-scale factors affect the function of weed seed predation. In this paper, we report on specific researc…

Ex ante evaluation of gene flow in oilseed rape with cropping sytem models

2009

International audience

Species-specific prey choice of carabid beetles in European cereal fields

2017

National audience; Trophic interactions between species in agroecosystems provide key regulation ecosystem services and therefore also determine the dynamics, robustness and resilience of service provision. To achieve international goals of reducing application of pesticides without compromising key provisioning ecosystem services such as crop yield, recent research attaches importance to the biological control potential of carabid beetles. However, apart from feeding on pest species and weed seeds, carabids also consume non-pest prey (alternative prey) such as collembolans and earthworms, which can play a contradictory role in the efficacy of pest and weed control. Most carabids are descri…

Regulation of legume seed size by an endosperm-expressed transcription factor

2015

BAP Pôle GEAPSI; International audience; There are numerous reports of transcription factors (TFs) which are implicated in the control of seed size and seed composition. We have identified, using a platform of TF sequences derived from the Medicago truncatula genome sequence, a class of TFs specifically expressed during the seed filling stage. One such TF, DASH, was shown to be confined to the developing endosperm. We investigated the role played by DASH through analysis of mutant alleles. These give rise to seed-lethal or near-lethal phenotypes, with degeneration of the endosperm and arrested embryo development. The relation of this phenotype to seed auxin action was investigated.

Impact of fertilization, tillage and direct seeding on nitrate reducers in Madagascar

2007

Spatio-temporal dynamics of weed seed eating carabid species in agricultural mosaics: variation of annual habitat quality of oil seed rape and role o…

2017

National audience; Carabid beetles are considered as important contributors to the regulation of weeds and recent studies have shown that weed seed predation by carabids may partly substitute for herbicide use in agriculture. Enhancing this ecosystem service requires to understand the spatio-temporal distribution of these species during the cropping season. Infra-annual variation in the spatial distribution of ground beetles within agricultural mosaics is less documented but of prime importance given that agricultural landscapes are highly dynamics. Indeed, crop phenology, agricultural operations but also habitat requirements during life cycle can lead to a redistribution of individuals bet…

Analysis of eIF4E gene sconfering resistance to Pea seed-borne mosaic virus (PSbMV) and other potyviruses in pea

2013

Pea seed-borne mosaic virus (PSbMV) belongs among the most frequent viral pathogens causing severe losses in field pea and other legumes. These losses might be prevented by growth of resistant varieties. Resistance to the common P1 strain of PSbMV isconferred by a single recessive gene (eIF4E), localized on LG VI (sbm-1 locus), while to lentil L1 strainis localized on LGII atsbm-2locus. Gene-specific single nucleotide polymorphism and co-dominant amplicon length polymorphism markers were developed. From the comparison of genotype verses phenotype for selection of resistance/susceptibility in F2 plants, there was a 26% discrepancy between the PCR and ELISA-based assays with potentially susce…

Does grassland cover limit the replenishment of weed seed banks during seed rain?

2012

International audience

The contribution of M. truncatula to the understanding of complex developmental processes in legumes: the case for seed reserve accumulation

2009

National audience