SYMBIOSIS

Author: ALGUACIL GARCIA M. MAR.
Year: 2003.
University: MIGUEL HERNÁNDEZ DE ELCHE [www.umh.es].
Place of defense: ESCUELA POLITÉCNICA SUPERIOR.
Place of preparation: ESCUELA POLITÉCNICA SUPERIOR DE ORIHUELA.

Summary: We conducted a field experiment in revegetation for a period of 18 months, with the aim of checking the influence of alóctono inoculation with a fungus, Glomus claroideum and with a mixture of endófitos native isolated from the experimental area (Sierra Pcarcho, Cieza, Murcia), on some physiological parameters of the plants (photosynthetic rate, stomatal conductance, efficient use of water, nitrate reductase enzymes and antioxidants isotopes of C13 and N15), growth parameters (aboveground biomass and root, basal diameter and height), foliar nutrients (N, P, K) and percentage of micorrización. The plants used in the trial were native shrubs of the Mediterranean basin: Olea europaea, Pistacia lentiscus, Retama sphaerocarpa and Rhammus lycioides. It was also established that took effect two types of inoculum used biochemical parameters on the ground (enzymatic activities: urease, protease, acid phosphatase, glucosidasa and dehydrogenase and glomalina easily removable), physical parameters (stability of aggregates and bulk density), chemical parameters (Ntotal, Pasimilable, Pextraíble, CS, CHS; CHT), physical and chemical parameters (electrical conductivity and pH), and also identified the potential micorrícico soil. This study concluded that treatment of inoculation with the mixture of endófitos native was the most effective for establishing the four shrub species native studied in a semiarid area degraded. But for improving soil quality and the physiological parameters of plants, the effectiveness of native fungi depends largely on the host species.

Author: MARÍA DE LAS HERAS NURIA DE.
Year: 2003.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLOGÍCAS.
Place of preparation: CIENCIAS MEDIOAMBIENTALES (CSIC).

Summary: In this thesis is carrying out a esnid ~ ointegra ~ or symbiosis Lupinus albus-Bradyrhizobium sp. (Lupinus) y.el effect quesóbre this symbiosis produces the herbicide glyphosate in the microsimbionte,. Rhizobium species, as in the macrosibionte, the legume. This herbicide f ~ cta.drástisamente the fixing desimbiótica nitrogen lupine plants. The decline in aCtividad niti9genasa is due to the inhibition of physiological processes in the cytosol of the node rather than a direct effect on the enzyme. The application of glyphosate produced changes in elmetabolismo carbon. The decline in the starch content alongside the activity Sucrose Sintasa explain the involvement of the enzyme in the synthesis of starch. Both reductions in addition to the increase in sucrose, relate to the altered route of aminomidos aromatic biosynthesis by the glifosató .. Moreover, the Glyphosate inhibits the growth in free life Bradyrhizobilfm'sp. (Lupinus), with increased tolerance to treatment by the plant 'by the miCrosimbionte. There were changes in the ultrastructure of the nodule and the photosynthetic apparatus, progressive and differentials. The ultrastructural alterations observed in the node points out, the breakdown of the membrane bacteroidal from the concentration 2.5 mM glyphosate, and the high density of electronic cytoplasm by intense activity lithic. The 'concentrations of acid shikímico and protocatéquico increase in the nodules and leaves Lupinus albus quickly after the application of glyphosate. Treatment with glyphosate has shown a direct correlation between the accumulation of phenolic compounds, and the decline in activity nitrogenasa. The detection of a new polypeptide cle44 kDa protein in the pattern of sitosol bacteroidal was altered. Outstanding prodúcida by glyphosate in the metabolism of proteins. This protein, called BLpp is encoded by. A single gene in the bacterial genome and studies of gene expression of this protein indiCan that levels of expression of the gene blpp increase in nodules with increasing concentration of glyphosate, suggesting a transcriptional regulation of the gene. However, in free-living bacteria was detected RNA accumulation was only when grown in the absence of glyphosate, indicating differences in their pattern of expression in free life and symbiosis. Also, the structure of the protein BLpp have identified two reasons: a partnership membrane and another characteristic of the family of porinas, suggesting that the protein BLpp is a "possible" porina. This would be the first porina described in lá bacterium Bradyrhizobium sp. (Lupinus)