Photoinduced Electron Paramagnetic Resonance Research Articles

Electron Paramagnetic Resonance in Spinach Chloroplasts at Low Temperature

PHOTO-induced electron paramagnetic resonance signals in green plant material have been investigated for many years1–4. The description of the parts played by these unpaired electrons in the energy conversion processes of photosynthesis still remains a challenge. This communication describes the initial results of an approach based on the examination of the electron paramagnetic resonance signals at low temperature. It is hoped that the interpretation of the results is simplified in frozen systems by the possibility of excluding mechanisms that proceed with negligible rate in this state, for example, enzymatically catalysed reactions. Thus the observed changes in electron paramagnetic resonance signal intensity are expected to occur near the beginning of the energy conversion sequence in photosynthesis.

Photo-induced electron paramagnetic resonance in mutant photosynthetic species lacking carotenoids or chlorophyll.

Abstract The association of the photo-induced electron paramagnetic resonance signal in photosynthetic tissue with the necessity for the presence of chlorophyll is demonstrated with a variety of mutant organisms. This is taken as additional evidence of the direct electron-transfer reaction from and/or to chlorophyll as the primary quantum conversion step.

Photo-Induced Electron Spin Resonance in Solutions of Some Electron-Donor-Acceptor Complexes.

Photo-Induced Electron Spin Resonance in Solutions of Some Electron-Donor-Acceptor Complexes.

Primary Quantum Conversion Process in Photosynthesis: Electron Spin Resonance

Photoinduced electron spin resonance signals have been observed in isolated chloroplasts and other green materials with a growth time not affected by reducing the temperature to -140 deg. This is interpreted in terms of conduction-band and trapped-electron theory.