ENERGY STORAGE STATES OF PHOTOSYNTHETIC MEMBRANES: ACTIVATION ENERGIES AND LIFETIMES OF ELECTRONS IN THE TRAP STATES BY THERMOLUMINESCENCE METHOD |
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| Authors: | V. G. Tatake T. S. Desai Govindjee P. V. Sane |
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| Affiliation: | Biology and Agriculture Division, Bhabha Atomic Research Centre, Trombay, Bombay 400 085, India;Departments of Physiology and Biophysics and Botany, University of Illinois, Urbana, IL 61801, USA |
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| Abstract: | Abstract Several methods discussed by R. Chen (1969) were used for the calculation of the activation energies ( E ), frequency factors ( s ) and mean lifetimes of electrons in trap states at glow peak temperatures ( T m) and at room temperature ( T r) from thermoluminescence glow peaks in spinach chloroplasts and Euglena cells. Results are presented for E calculated independently, i.e. without any assumptions regarding the frequency factors which were determined subsequently using the activation energy values thus calculated. The most reliable values for E , s, r( T m) and ( T r) for the well-resolved glow peaks Z(118 K), I(236 K), II(261 K), III(283 K), IV(298 K) and V(321 K) are as follows:
The present comprehensive study has been compared with the earlier ones and the significance of the observed high frequency factors is discussed. It is concluded that only peaks I and II, related to photosystem II, follow the Randall–Wilkins (RW) theory, whereas peaks IV and V, related to photosystem I, do not. |
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