Search results for "TRES"

Stimulation of root and somatic embryo production in Euconymus europaeus L. by an inhibitor of polyamine biosynthesis

1995

In vitro formation of roots and somatic embryos is obtained from cotyledon explants of a Spindle tree (Euonymus europaeus L.) cultured on two different media: a medium inducing callus formation and the production of roots, and a medium inducing callus formation, root and somatic embryo production. We studied the effects of α-difluoromethylornithine (DFMO), a specific, irreversible inhibitor of ornithine decarboxylase (ODC) on root and somatic embryo production, growth and titers of putrescine in Euonymus explants and explant-derived calli. Early changes in putrescine levels were detected in both cultures before the visible emergence of roots or somatic embryos. DFMO rapidly inhibited putres…

Qualité et performance de plants de Douglas soumis à différentes contraintes hydriques

1999

An experiment was carried out on 12 Douglas fir seedlings lots that were 3 years old and had all originated from the same seed lot. Treatments consisted in combining stock type with three different height to diameter ratios, storage duration and method (long at 2°C or short in various conditions), and protection from desiccation (by bagging or not). Seedling lots were assessed at planting by root electrolyte leakage (REL), root moisture content (RMC) and predawn shoot water potential (Ywp). They were planted simultaneously in well-watered or water-stressed conditions. Performance level was based on survival and height growth at the end of the growing season. Slender seedlings not bagged had…

Prévalence de pathogènes humains dans les sols français, effet des facteurs pédoclimatiques, biologiques et du mode d'utilisation des sols

2013

Soil contamination by bacterial pathogens can occur through manure, sewage sludge spreading or irrigation using waste water treatment plants effluents. Agricultural soils may act as reservoirs for these pathogens, play a significant role in their dissemination, leading to the potential contamination of food and water resources. Health risk associated with the occurrence of pathogens in environmental matrices has to be thoroughly evaluated. In this context, the objectives of this work were: i) to determine the prevalence of two pathogenic bacterial species (Listeria monocytogenes and Enterococcus faecalis) in a large collection of French soils originated from a systematic soil survey of the …

La lutte biologique contre l'ambroisie à feuilles d'armoise illustrée par l'exemple d'Ophraella communa: quels intérêts et quelles limites ?

2016

National audience; Common ragweed (Ambrosia artemisiifolia) was introduced in France over 150 years ago and its spreading across France now seems inexorable. The specific biology of this summer annual creates new problems for the managers of the various habitats where the plant can be found. The reduced possibility, or even the impossibility, to use traditional control means in certain environment conditions brings managers to consider biological control as one of the few possible means for slowing down the spread, or even pushing back the distribution area, of this invasive and allergenic plant. With Ophraella communa as an example, a reflection is presented on the benefit-risk balance of …

Correlating stress and somatic embryogenesis for NBT: myth or reality?

2018

Global warming and growing demography have increased demand for agronomic resources, leading to increasing lack of land suitable for agriculture and provoking several abiotic stresses which, added to biotic ones, result in physiological and metabolic disorders that impact on crop yield when most needed. Reducing this impact is a major scientific and agronomic challenge and biotechnology would be an efficient alternative. However, to reduce risks of somaclonal variation among regenerants it is better to produce them by somatic embryogenesis directly from explants or gametes, or indirectly from callus or cell suspensions. Thus, globular embryos regenerate and develop through to the heart, tor…

Developing fall-sown pea cultivars as an answer to the challenges of climatic changes

2012

Chapitre 4; International audience; Pea is considered rather well adapted to wide temperature ranges, with seedlings able to survive even -20 °C. From a physiological viewpoint, pea becomes tolerant to frost if first exposed to low non-freezing temperatures, causing the so-called cold acclimation. Delayed floral initiation helps some forage pea genotypes to escape the main winter freezing periods, as susceptibility to frost increases during the transition to the reproductive state. The oldest winter pea cultivars carry the dominant allele, Hr, although some bear hr. They are generally characterized by prominent winter hardiness and a long growing season, from sowing in early October until e…

Comment le mode de nutrition azotée influence-t-il le prélèvement, le stockage et la remobilisation des nutriments en conditions hydriques fluctuante…

2019

National audience; Pea seeds have interesting nutritional properties through their protein, vitamin and mineral contents. However, environmental conditions such as soil water availability during plant growth influence both final yield and seed quality in pea. Soil water conditions not only modulates pea nitrogen acquisition whatever the mode of nitrogen nutrition: mineral nitrogen acquisition by roots and atmospheric di-nitrogen fixation by nodules in interaction with rhizobia, but also the overall plant mineral nutrition. The aim of this study is to get a better understanding of soil water deficit impact on nutrient acquisition, storage and distribution inside the plant according to the mo…

Impact d'un déficit hydrique sur Pisum sativum cv. Kayanne cultivé dans du sol en RhizoTubes

2018

Stress hydriques répétés…exite-t-il un effet mémoire ?

2017

Transcriptional response of Medicago truncatula sulphate transporters to arbuscular mycorrhizal symbiosis with and without sulphur stress

2013

Sulphur is an essential macronutrient for plant growth, development and response to various abiotic and biotic stresses due to its key role in the biosynthesis of many S-containing compounds. Sulphate represents a very small portion of soil S pull and it is the only form that plant roots can uptake and mobilize through H(+)-dependent co-transport processes implying sulphate transporters. Unlike the other organically bound forms of S, sulphate is normally leached from soils due to its solubility in water, thus reducing its availability to plants. Although our knowledge of plant sulphate transporters has been growing significantly in the past decades, little is still known about the effect of…