Relationship between photosynthetic capacity, nitrogen assimilation and nodule metabolism in alfalfa (Medicago sativa) grown with sewage sludge

Rhizobium tropici exopolysaccharides as carriers improve the symbiosis of cowpea-Bradyrhizobium-Paenibacillus

“…This response reinforces the idea that the flow of photosynthetically fixed carbon was directed to support root and nodule growth (Larrainzar et al, 2009;Magori and Kawaguchi, 2009;Masson-Boivin et al, 2009;Voisin et al, 2010). During the vegetative stage, the photosynthetic rate has a greater effect on the total dry mass and decreases sharply as the pods begin to develop, which is probably related to the decreased total nitrogen content of Rubisco activity (enzyme responsible for fixing CO 2 during photosynthesis) and the integrity of the nodules (Antolín et al, 2010;Krapp et al, 2011). This affirmation is supported by the decrease in viable nodules in plants that were collected at grain filling, probably in response to the natural process of senescence.…”

“…Plant species differ in growth dynamics according to the supply of nitrogen and carbon (Rinnofner et al, 2008;Krapp et al, 2011). As observed in this study, uninoculated plants altered the root growth, probably in response to low nitrogen concentrations in the soil solution (Rinnofner et al, 2008;Antolín et al, 2010). Additionally, cowpeas co-inoculated simultaneously with Bradyrhizobium sp.…”

“…Some microbial combinations can increase the nutrient availability to plants, the quality of the plant root system, plant productivity and the BNF (Antolín et al, 2010;Rodrigues et al, 2013b). Legume-rhizobia symbiosis plays an important environmental role, reducing the use of mineral nitrogen fertilizers, which have high costs and minimize environmental risks, such as the eutrophication of water resources (Krapp et al, 2011).…”

“…Increased nodulation and plant growth promotion have been associated with the presence of PGPB in the root environment (Magori and Kawaguchi, 2009;Antolín et al, 2010). Indeed, the number of nodules, specific nodulation and nitrogen-fixation efficiency -all measured in the nodules -increased in response to the presence of PGPB, mainly in plants that were co-inoculated simultaneously with Bradyrhizobium sp.…”

Changes in alfalfa forage quality and stem carbohydrates induced by arbuscular mycorrhizal fungi and elevated atmospheric CO2

“…An enhanced photosynthetic rate may have allowed increased translocation of sugars from leaves to roots, thus favouring nodule development in NM plants under elevated CO 2 (Fig. 1A) and, vice versa, the presence of N 2 -fixing bacteria associated with roots of alfalfa could have enhanced the rate of photosynthesis as a consequence of the increased sink: source ratio due to C costs of N 2 fixation (Antolín et al, 2010). In contrast, the nodule DM per plant was similar in M plants grown at ambient CO 2 to those exposed to elevated CO 2 (Fig.…”