Exploitation of somaclonal variability for the search of saline-tolerant potato (Solanum Tuberosum L.)

The present investigation was conducted with an aim to study the effect of salt stress (NaCl) on in vitro potato callus growth and the potential for exploiting this technique in improving salinity tolerance in potato. The results in the four varieties in the culture medium showed a decrease in all studied parameters like callus growth, relative average growth, water content and salinity sensitivity coefficient upon increasing the salinity of the medium in calluses. It has also been observed that the type of callus has a large effect on the above-mentioned parameters in which better callus growth adapted to 150 mmol NaCl is obtained than unsuitable calli in the same culture medium

Strategies and adaptation mechanisms of legumes to low phosphorus availability in soils

Les légumineuses sont bien reconnues pour leur impact sur la durabilité des systèmes agricoles ainsi que pour leurs bienfaits nutritionnels et sanitaires. La faible disponibilité des sols en phosphore (P) est un facteur nutritionnel majeur limitant la production de légumineuses, en particulier dans les régions méditerranéennes et tropicales. La déficience en P limite la fixation de N2, car elle a été décrite comme ayant un fort impact sur la croissance et la survie des rhizobia et de la plante hôte. Les légumineuses ont évolué des mécanismes complexes pour faire face à la limitation en P.  Cette revue décrit les différents processus (modifications des racines, des anions organiques, des enzymes) qui peuvent affecter la biodisponibilité du P dans la rhizosphère. En réponse à la déficience en P, les plantes utilisent diverses stratégies adaptatives pour améliorer la disponibilité du P dans le sol et leur efficacité d'absorption, ce qui implique des modifications dans l'architecture des racines nodulées, l'acidification de la rhizosphère et l'induction de gènes impliqués dans l'efficacité d'utilisation du P, tels que les transporteurs de Pi à haute affinité et les enzymes phosphatases. Les réponses moléculaires, biochimiques, physiologiques et morphologiques sont déclenchées pour stimuler l'absorption de Pi dans le sol ou pour optimiser son efficacité d'utilisation et sa répartition intracellulaire sur tous les organes végétaux. Une compréhension holistique des mécanismes de la tolérance des légumineuses aux contraintes abiotiques sera précieuse pour les stratégies visant à améliorer l’agriculture durable dans un monde où la population augmente et les ressources renouvelables en déclin. Mots-clés : Légumineuses, poils racinaires, anions organiques, enzymes, déficience en phosphoreLegumes are well recognized for their impact in the sustainability of agricultural systems as well as for their nutritional and health benefits. Low availability of soil phosphorus (P) is one of the factors limiting the production of legumes, particularly in the Mediterranean and tropical areas. P-deficiency limits N2 fixation, since it has been described to have a strong impact on the growth and survival of both rhizobia and host plant. This review describes the different processes (root changes, role of pH, organic anions, and enzymes) that affect the availability of P in the soils. In response to P-deficiency, plants use various adaptive strategies to improve soil P availability and their uptake efficiency, which involves modifications in nodulated-root architecture, rhizosphere acidification, and induction of genes involved in P use efficiency such as high-affinity P transporters and P-hydrolyzing phosphatases enzymes. Molecular, biochemical, physiological and morphological responses are triggered to stimulate soil Pi uptake or to optimize its intracellular use efficiency and allocation over all plant organs. A holistic understanding of the key mechanisms underlying legume tolerance to abiotic constraints will be valuable for strategies to improve sustainable agriculture in a world of increasing population and declining renewable resources. Keywords: Legumes, root hairs, carboxylate, enzymes, phosphorus deficienc

Intercropping Promotes the Ability of Legume and Cereal to Facilitate Phosphorus and Nitrogen Acquisition through Root- Induced Processes

Intercropping of cereal and legume can improve the use of resources for crop growth compared to cropping system. An increase in soil phosphorus (P) and nitrogen (N) acquisition by root-induced biochemical changes of intercropped species has been reported as key processes of facilitation and complementarily between both intercropping legumes and cereals. Indeed, the functional facilitation prevails over interspecific competition under nutrients limiting for crop growth. Results showed that P availability significantly increased in the rhizosphere of both species, especially in intercropping under the P-deficient soil conditions. This increase was associated with high efficiency efficiency in use of rhizobial, plant growth and resource use efficiency as indicated by higher land equivalent ratio (LER) and N nutrition index. In addition, the rhizosphere P availability and nodule biomass were positively correlated (r2 = 0.71**, and r2 = 0.62**) in the intercropped common bean grown at P-deficient soil. The increased P availability presumably improved biomass and yield in intercropping, although it mainly enhanced intercropped maize grain yield. Exploiting belowground parameters in a legume-cereal intercropping is likely necessary to maximize rhizosphere-interspecific interactions as a strategy to improve the symbiotic rhizobial efficiency and microbial activities, as a result of root-induced pH and N availability changes under low P soils

Manifestations du script de cohésion Dans la Communauté Mohammed Eid Al-Khalifa

This study tagged: manifestations of cohesion script in Community " Mohammed Eid Al Khalifa," tried to investment criterion of cohesion manifestations (mechanisms) to prove or deny the social cohesion of the poems assigned to the study and analysis. The research was divided into the entrance of the two as follows: Entrance: marked: linguistics sentence to the text, which dealt with a view of a light sentence and types when the old and modern at. Then moved on to speak about the text and text linguistics in terms of concept; text: What goes up or appear in the form of verbal event represented by voice or written in the form of production represents and show writing, with reference to the differences between text linguistics and linguistics of the sentence. Chapter I: separation of theoretical Marked: coherence script concept and manifestations, as is the casting or consistency when most researchers online structure of the surface form of the text; that regard relations grammatical or lexical different in the text, it is this respect means to be achieved whereby the continuity (semantic) in the apparent meaning of the text. The knitting or harmony is related to the deep structure of the text at the level of the underlying perceptions and concepts that shape the world of the text. Chapter II: separation applied, Marked By: manifestations of cohesion script in the Community Mohammed Eid Al-Khalifa, which dealt with the nine poems from these meetings, namely: the poem "ship of death", and the poem "Hey France", and the poem "on the people," and the poem " Be strong, "and the poem" Do not forget, "and the poem" agitated and serious, "and the poem" The risk to human science "and the poem" O my people endowed, "and the poem" the words of the people. " The conclusion of this research included reviewing the most important findings, including: - the proportion of variation and the manifestations of a script in the Community Cohesion poet Algeria Mohamed Eid Al-Khalifa, it features Alazakip found in grabbing the attention of: * The assignment of various kinds, especially the referral of conscience, which we found in the Code refer to either search the Algerian people, or to French colonialism. This kind of assignment contributes to the formation of the overall meaning of the text through the relocated inside, and also by reference. Not to mention the deletion of the poet, who took care of him much attention as other aspects. * Repetition of most forms of private frequency, which dominated the overall blog search, Repetition is a tributary Atsakie draw the meanings of the poet and confirmed. * Accretion forms and relations on the level of one house, and at the level of betaine, and the level of the poem (text) as a whole. It is these relationships that have emerged clearly in the Code of The Relation of contrast, does not hide what this relationship is of importance in the disclosure of the meanings and clarified, a canter identify things. * Connectivity with his tools, different, special tools according to which an absolute plus, and tools that benefit the branching, leading to a consistency of part with part (part with the part), and consistency and harmony of the house with the home, harmony and coherence of the poem (text) as a whole. * All types of parallelism: parallelism fully horizontal, vertical and parallel full, partial and parallel horizontal, vertical and parallel partial. This element Alazaki appeared in the Search Blog at the level of nominal sentences branches (especially the nominal sentence installed), and at the level of branches as well as verbs (especially related to the actual installed). This evidence reflects the psychological poet optimistic for tomorrow for Algeria to enjoy the freedom, security and stability, and also reflects the distinctive feature of the reform of the poet, emerging from the sincerity of his faith and piety. - when we talked about in the times of the text and found that the time mostly on the Community Mohammed Eid Al-Khalifa is the last time the right as we have to list the events and the report of the facts, the poet is sincere in all of the facts conveyed to us, especially those depicting the suffering of the Algerian people during the French colonialism, that the poet actually lived and lived through all the bitterness. - The study confirmed that the texts in the Community Mohammed Eid Al-Khalifa, can not be understood isolated from the social context, mostly poetry Mohammed Eid was felt appropriate. From all this we can God knows these poems Social studied as a coherent text to a large extent, comes to us thanks to the availability of this provision aspects of the formal coherence of the text surface (consistency), and also the availability of the manifestations of the deep semantic coherence script (harmony)

Des transferts de rupture

On analyse ce qui se met en jeu dans l’accueil d’adolescents placés/déplacés d’un lieu d’accueil à l’autre, sous couvert des réorientations en réponse à leurs agirs incessants. Comment entendre ce moment où l’adolescent s’anime par son corps en empruntant la scène institutionnelle ? Quels sont les effets cliniques de la mise au-dehors – par l’éjection – du transfert de l’adolescent sur l’institution ? On dépliera ces différentes questions qui tissent la pratique clinique avec des adolescents accueillis par des équipes éducatives pour repérer ce qui ne cesse de revenir à la même place, alors qu’il s’agit de positions asymétriques. Les questions centrales sont : Pour qui l’éjection/réorientation de l’adolescent fait-elle rupture ? Comment une institution accueillant des adolescents peut-elle travailler contre son projet et prolonger la malveillance parentale ayant conduit aux placements des enfants ? Cette dernière question vise la place accordée au transfert adolescent en institution et l’insupportable création d’altérité qu’il véhicule

Nodular diagnosis of contrasting genotypes for rhizospheric phosphorus in [i]Phaseolus vulgaris[/i]

Legumes have the capacity to fix large amounts of atmospheric N2 into the biosphere through their symbiosis with soil rhizobia. However this legume contribution to the N bio-geochemical cycle varies with the nodulated-root rhizospheric environment, in particular phosphorus availability. In order to assess the environmental constrains that might limit this symbiosis, a nodular diagnosis was performed in field-sites chosen with farmers of the Mediterranean basin, with common bean as a model grain-legume, and a major source of plant proteins for world human nutrition. The engineering of the legume symbiosis is addressed by participatory assessment of bean recombinant inbred lines contrasting for their efficiency in use of phosphorus for symbiotic nitrogen fixation. Withthis methodology, a large spatial and temporal variation in nodulation and in the efficiency in use of the rhizobial symbiosis for plant growth, with a positive effect of the later on soil P-bioavailability. Soil P availability was a major limiting factor of the rhizobial symbiosis. It is concluded that by increasing the phosphorous use efficiency for symbiotic nitrogen fixation, a virtuous cycle of fertility is activated within legume rhizosphere, which can contribute to the sustainability of agricultures through the use of appropriate legumes and cultural systems

Role of acid phosphatase in the tolerance of the rhizobial symbiosis with legumes to phosphorus deficiency

International audiencePhosphorus (P) deficiency initiates a myriad of transcriptional, biochemical and physiological responses stimulating either the root’s extracellular abilities to acquire soil P in the rhizosphere or optimize its intracellular use efficiency and allocation through all plant organs. Enhancing activity of acid phosphatase (APase) to acquire and remobilize Pi from organic P compounds is one important strategy for improving plant P nutrition. The release of APase to the rhizosphere is a typical and almost universal P-starvation response in higher plants. However, relatively little is known about the functions of intracellular APase in legume nodules. The aim of this review was to track the enzyme activity along with the intra-nodular localization of APase, and its contribution in the rhizobial symbiosis tolerance to P-deficiency. Our findings have revealed that expression of APase and phytases genes and activities of the corresponding enzymes were positively correlated with increases both of the P use efficiency for N2 fixation and nodule O2 permeability in the rhizobial symbiosis with legumes. The induced enzyme activity and the marked transcripts localization of APase and phytase in nodule cortex would control nodule respiration and contribute to adaptation of nodulated legumes to low-P availability. Thus, the increase of APase and phytase activities in legume nodules supports a physiological role of these enzymes in the regulation of nitrogenase activity in connection with the nodule-P status, and opens up a new scenario for a better understanding of the regulation of N2 fixation in legumes

Phosphorus deficiency affected permeability to O2 and phytase gene expression in nodules of Phaseolus vulgaris-rhizobia symbiosis

Under phosphorus (P) deficiency, sensitivity of the N2-fixing legumes increases since the large amount of P-dependent carbon and energy turnover required during N2fixation are not satisfied. However, despites the fact that these crops have been widely characterized under P-deficiency and a number of tolerance traits have been identified, abilities of the nodules to cope with this environmental constraint have still to be further investigated. Increases both of activity and gene expression of acid phosphatases (APases) are among mechanisms that lead to increase both of N2fixation and nodule respiration under P-deficiency. Our findings have revealed that activities and differential expression of phytase transcripts were positively correlated with increases both of the rhizobial symbiosis efficiency (EURS) and nodule O2 permeability. Under P-deficiency, this positive correlation was more significant for the P-efficient RIL115 than for the P-inefficient RIL147. It is concluded that the induced enzyme activity and the marked transcript localization of this phytase in nodule cortex would control nodule respiration and contribute to adaption of nodulated legumes to low P availability

High yields in a low-P tolerant recombinant inbred line of common bean under field conditions

International audienceLow phosphorus (P) availability is a primary factor that limits the production of common bean (Phaseolus vulgaris L.) in many parts of the world, especially when plant growth depends on N2 fixation. In order to understand how common bean copes with this nutritional constraint, two recombinant inbred lines (RILs) of common bean namely RILs 115 and 147 were studied in the field conditions during three growing seasons from 2012 to 2014. At flowering stage, plants were harvested and analyzed for their nodulation, growth, P content and yield. Results showed that for RIL115, the nodulation (43%), shoot (28%) and root growth (32%) was higher than for RIL147 in a low-P availability soil whatever the growing season. In addition, RIL115 had better growth and efficiency in use of P for the rhizobial symbiosis (7.29 mg nodule dry weight mg−1 nodule P) about twice higher may be involved in tolerance to low-P, and to be a useful marker for field data. At harvest, the RIL115 showed higher grain yield (1146 kg ha−1) than the RIL147 (1045 kg ha−1). It is concluded that the genotype of RIL 115 had a higher yield and could best adapt to low-P availability under field condition