Intraspecific Competition in Lucerne and Relationships with Reserve Availability

Below-ground reserves are thought to provide an indication of a forage potential for shoot regrowth after defoliation. The aim of this work was to re-evaluate the causal relationships existing between organic reserves (non-structural carbohydrates and N reserves) and shoot regrowth of alfalfa. The variations brought about by cultivar differences (cv Lodi or Europe), length of the previous regrowth period (30 or 45 d), or by intraspecific competition for light within a dense canopy, were studied. Field grown plants were harvested at weekly intervals, and separated as dominant, intermediate and suppressed plants. Shoot regrowth yield was determined and taproot were analyzed for starch, N, soluble proteins and vegetative storage proteins. Results showed that taproot starch and N contents were modified by the length of the previous regrowth but not by the position of the plant within the canopy. Soluble protein or VSP concentrations increased with the length of the previous regrowth, and with a higher position of the plant within the canopy. Shoot regrowth yield was linearly related to taproot soluble protein and VSP contents on day of defoliation, but relationships were not found with initial starch or N contents. These results suggest that root protein and VSP are key organic nutrient for alfalfa shoot regrowth after harvest

Plant N Fluxes and Modulation by Nitrogen, Heat and Water Stresses: A Review Based on Comparison of Legumes and Non Legume Plants

Chapter 5International audienc

Copper-deficiency in Brassica napus induces copper remobilization, molybdenum accumulation and modification of the expression of chloroplastic proteins

During the last 40 years, crop breeding has strongly increased yields but has had adverse effects on the content of micronutrients, such as Fe, Mg, Zn and Cu, in edible products despite their sufficient supply in most soils. This suggests that micronutrient remobilization to edible tissues has been negatively selected. As a consequence, the aim of this work was to quantify the remobilization of Cu in leaves of Brassica napus L. during Cu deficiency and to identify the main metabolic processes that were affected so that improvements can be achieved in the future. While Cu deficiency reduced oilseed rape growth by less than 19% compared to control plants, Cu content in old leaves decreased by 61.4%, thus demonstrating a remobilization process between leaves. Cu deficiency also triggered an increase in Cu transporter expression in roots (COPT2) and leaves (HMA1), and more surprisingly, the induction of the MOT1 gene encoding a molybdenum transporter associated with a strong increase in molybdenum (Mo) uptake. Proteomic analysis of leaves revealed 33 proteins differentially regulated by Cu deficiency, among which more than half were located in chloroplasts. Eleven differentially expressed proteins are known to require Cu for their synthesis and/or activity. Enzymes that were located directly upstream or downstream of Cu-dependent enzymes were also differentially expressed

Contribution a l'etude du metabolisme de l'azote chez le ray-grass anglais en depart de croissance apres une coupe

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Modelling of nitrate uptake, N translocation and remobilisation based on short term 15N labelling in Brassica Napus L.

International audienc

Modélisation de l'absorption de l'azote nitrique, de son allocation et de sa remobilisation chez le colza d'hiver (Brassica napus L.) de la reprise de la végétation au stade maturité des graines

PARIS-AgroParisTech Centre Paris (751052302) / SudocSudocFranceF

Mise en réserve d'azote sous forme de protéines de réserve des organes végétatifs (VSP) chez medicago sativa L. et brassica napus L. : principaux facteurs de régulation

Chez la luzerne (Medicago sativa L.) et le colza (Brassica napus L.), des protéines de réserve des organes végétatifs (VSP : vegetative storage protein) accumulées dans le pivot sont fortement impliquées dans la fourniture et le stockage d'azote. L'accumulation des VSP sous l'effet d'une héméropériode courte ou d'une application de méthyl-jasmonate, chez la luzerne ou au cours du développement chez le colza, résulterait d'une action directe (induction des gènes) et indirecte (via la modification des relations source-puits pour l'azote). Chez la luzerne, alternativement à leur fonction de réserve, les VSP pourraient avoir un rôle dans la survie hivernale et la protection contre les pathogènes, comme l'atteste la découverte récente d'une homologie de séquence de l'une des VSP avec des chitinases. Chez le colza, la VSP pourrait constituer une réserve azotée "tampon" révélatrice du changement de statut source-puits pour l'azote de la plante et posséder ainsi un rôle qualitatif.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

REMPLISSAGE EN AZOTE DES TISSUS REPRODUCTEURS DE BRASSICA NAPUS L. (ESTIMATION DES FLUX PAR MARQUAGE ISOTOPIQUE, CARACTERISATION DES PROTEINES IMPLIQUEES DANS LA MISE EN RESERVE ET DES FACTEURS INDUISANT LEUR ACCUMULATION)

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Etude et modélisation des effets de l'intensité de la coupe et du niveau des réserves organiques initiales sur la dynamique de l'azote et du carbone au cours de la repousse chez la luzerne (Medicago sativa L.)

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

ETUDE DE L'ABSORPTION DU NITRATE CHEZ BRASSICA NAPUS L. (EVOLUTION DE L'ACTIVITE DES TRANSPORTEURS ET DE LA TRANSCRIPTION DES GENES NRT1 ET NRT2 EN REPONSE A UNE PRIVATION EN NO 3, EVALUATION DE LEUR ROLE SUR LE CYCLE DE CULTURE)

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF