Biomaterial Database

Field concentration and temperature dependence of fluorescence polarization of magnetically oriented chloroplasts. 1982

E Papp, and G Meszéna

Chloroplasts in higher magnetic fields align with their equatorial plane perpendicular to the field. Because of the nonrandom orientation of the chromophores in the membrane the fluorescence radiation will be partially polarized. The chloroplast concentration, magnetic field, and temperature dependence of the fluorescence polarization has been investigated. The results are compared with a simplified model calculation. It is shown that the concentration dependence can be related to the linear dichroism of the fluorescence radiation and self-adsorption. Taking these effects into account results in the calculation of a higher fluorescence polarization (FP) ratio and higher inclination of chlorophyll dipoles to the membrane plane. Analyzing the magnetic field dependence of the FP ratio, we conclude that in a magnetic field not only will be chloroplasts be aligned, but the thylakoid stacks as well. A decrease in the FP ratio was observed around 20 degrees C. It is suggested that this decrease reflects a phase transition in the photosynthetic membrane.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D008280	Magnetics	The study of MAGNETIC PHENOMENA.	Magnetic
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D002736	Chloroplasts	Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.	Chloroplast,Etioplasts,Etioplast
D005453	Fluorescence	The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
D018521	Plant Physiological Phenomena	The physiological processes, properties, and states characteristic of plants.	Plant Physiological Processes,Plant Physiology,Physiology, Plant,Plant Physiologic Phenomena,Plant Physiologic Phenomenon,Plant Physiological Phenomenon,Plant Physiological Process,Phenomena, Plant Physiologic,Phenomena, Plant Physiological,Phenomenon, Plant Physiologic,Phenomenon, Plant Physiological,Phenomenons, Plant Physiological,Physiologic Phenomena, Plant,Physiologic Phenomenon, Plant,Physiological Phenomena, Plant,Physiological Phenomenon, Plant,Physiological Phenomenons, Plant,Physiological Process, Plant,Physiological Processes, Plant,Plant Physiological Phenomenons,Process, Plant Physiological,Processes, Plant Physiological