Graphite oxide as a support for palladium and rhodium complexes, assessed as catalysts for the partial hydrogenation of 1-heptyne

Graphite oxide (GO) was used to anchor [PdCl2(TDA)2] and [RhCl(TDA)3] (TDA =NH2(CH2)12CH3) with 2wt % of metal load. Elemental analysis (EA), FTIR, XPS, XRD and atomic absorption spectroscopy (AA) were the techniques employed for characterization. FTIR and XRD revealed that both complexes were mainly immobilized on the GO surface. The partial hydrogenation of 1-heptyne was the test reaction to evaluate the catalytic behavior of these heterogenized complexes under mild conditions of temperature and pressure in a semi continuous process. The results were compared with those obtained with the Wilkinson catalyst under the same operational conditions. AA analysis revealed that there is no leaching of the complexes during the heterogeneous catalytic evaluations. [RhCl(TDA)3]/GO was the best catalyst due to electronic and steric effects as well as the influence of the support

Trading direct for indirect defense? Phytochrome B inactivation in tomato attenuates direct anti-herbivore defenses whilst enhancing volatile-mediated attraction of predators

Under conditions of competition for light, which lead to the inactivation of the photoreceptor phytochrome B (phyB), the growth of shade-intolerant plants is promoted and the accumulation of direct anti-herbivore defenses is down-regulated. Little is known about the effects of phyB on emissions of volatile organic compounds (VOCs), which play a major role as informational cues in indirect defense. We investigated the effects of phyB on direct and indirect defenses in tomato (Solanum lycopersicum) using two complementary approaches to inactivate phyB: illumination with a low red to far-red ratio, simulating competition, and mutation of the two PHYB genes present in the tomato genome. Inactivation of phyB resulted in low levels of constitutive defenses and down-regulation of direct defenses induced by methyl jasmonate (MeJA). Interestingly, phyB inactivation also had large effects on the blends of VOCs induced by MeJA. Moreover, in two-choice bioassays using MeJA-induced plants, the predatory mirid bug Macrolophus pygmaeus preferred VOCs from plants in which phyB was inactivated over VOCs from control plants. These results suggest that, in addition to repressing direct defense, phyB inactivation has consequences for VOC-mediated tritrophic interactions in canopies, presumably attracting predators to less defended plants, where they are likely to find more abundant prey.Fil: Cortés, Leandro Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Weldegergis, Berhane T.. Wageningen University; Países BajosFil: Boccalandro, Hernan Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Dicke, Marcel. Wageningen University; Países BajosFil: Ballare, Carlos Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentin