Nitrogen-fixing stem nodules on Aeschynomene afraspera

Présentation d'#Aeschynomene Afraspera qui est une légumineuse tropicale qui se caractérise par de nombreuses nodulations sur la tige, fixateur d'azote. Grâce à ce potentiel de fixateur d'azote, #Aeschynomene Afraspera pourrait être utilisé en tant qu'engrais vert pour la rizicultur

Diversity of stem nodulation sites in Aeschynomene spp.

Présentation et analyse de 14 espèces de la légumineuse tropicale #Aeschynomene$ qui développe des nodules fixateur d'azote à la fois sur la tige et les racine

Nitrogen fixation in pure culture by rhzobia isolated from stem nodules of tropical Aeschynomene species

SUMMARY Asymbiotic nitrogenase activity was investigated in rhizobia strains isolated from stem and root nodules of several Aeschynomene species. All isolates from stem-nodulating species were able to develop nitrogenase activity ex planta in the presence or in the absence of combined nitrogen, whereas root isolates from Aeschynomene species related to the cowpea group of plants showed little or no activity. Nitrogenase activity in soft-agar and in liquid cultures displayed by strains ORS310 and ORS322, isolated from stem nodules of A. indica and A. afraspera respectively, was of the same order of magnitude as that found for Azorhizobium caulinodans ORS571 and ten times higher than for Bradyrhizobium strain CB756. Furthermore, like A. caulinodans ORS571, strains ORS310 and ORS322 were able to use atmospheric nitrogen as sole nitrogen source for growth. . None of these strains was able to grow at the expense of molecular nitrogen, except R. trifolii 0403, which was shown after a treatment involving succinate to behave physiologically similar as nodule-derived bacteroids. In free-living cultures of bradyrhizobia, nitrogen fixation always requires the presence of combined nitrogen and the fixed nitrogen is excreted into the culture medium [16]. Thus, in the free-living state as in the symbiotic conditions A notable exception among rhizobia isolates are the unusual strains from Sesbania rostrata stem nodules, now classified as a new genus. Azorhizobium caulinodan

Lyapunov functions, Identities and the Cauchy problem for the Hele-Shaw equation

This article is devoted to the study of the Hele-Shaw equation. We introduce an approach inspired by the water-wave theory. Starting from a reduction to the boundary, introducing the Dirichlet to Neumann operator and exploiting various cancellations, we exhibit parabolic evolution equations for the horizontal and vertical traces of the velocity on the free surface. This allows to quasi-linearize the equations in a very simple way. By combining these exact identities with convexity inequalities, we prove the existence of hidden Lyapunov functions of different natures. We also deduce from these identities and previous works on the water wave problem a simple proof of the well-posedness of the Cauchy problem. The analysis contains two side results of independent interest. Firstly, we give a principle to derive estimates for the modulus of continuity of a PDE under general assumptions on the flow. Secondly we prove a convexity inequality for the Dirichlet to Neumann operator.Comment: We have added some reference