FLUORESCENCE STUDIES ON PHOTOSYNTHETIC PIGMENT DEVELOPMENT IN RHODOPSEUDOMONAS SPHEROIDES * , †

When bleached, aerobically grown cells of Rhodopseudomonas spheroides are transferred to semi-aerobic conditions to induce bacteriochlorophyll synthesis, a new fluorescence band, with a maximum at 790 nm, is observed in addition to the 885 nm emission maximum normally seen in pigmented cells. The 790 nm fluorescence may be due to bacterio-chlorophyll which has not been bound into the chromatophore membrane. The quantum yield of the 885 nm fluorescence is at first relatively high and then, about 1 hour after transfer, drops to the level found in pigmented photosynthetic cells. The coupling to the rest of the photo-synthetic apparatus, as indicated by the effect of dithionite on the fluorescence, also seems to occur during the first hour of pigment development, which suggests that the onset of fluorescence quenching is due at least in part to the synthesis of photochemical reaction centers. Continuation of these studies should provide new information on the formation, structure and molecular interactions of the pigments and the photosynthetic membranes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73322/1/j.1751-1097.1968.tb08021.x.pd

ARS Workshop on Improving the Photosynthetic Capability and Biological Conversion of Solar Energy by Crops : January 21-23, 1975, Urbana, Illinois.

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Vortex Particle-Mesh Simulations of Atmospheric Turbulence Effects on Wind Turbine Blade Loading and Wake Dynamics

We develop a Vortex Particle-Mesh (VPM) method for the Large Eddy Simulation of wind turbine wakes and coarse scale aerodynamics. Based on the vorticity formulation of the Navier-Stokes equations, the approach combines the advantages of two discretizations. The particles handle the advection of vorticity, and exploit its compact support. The mesh is used for the evaluation of the differential operators and inside efficient Fourier-based Poisson solvers. The blades are modeled by means of lifting lines. This treatment is similar to a vortex lattice method, although it is here immersed in the mesh and allows the evolution of shed vorticity into a fully turbulent flow. We apply this tool to the investigation of atmospheric turbulence effects on the blade aerodynamics and on the wake behavior. To this end, the inflow boundary is feeding our VPM calculations with a turbulent vorticity field that has been computed in a preliminary LES of atmospheric turbulence