THE ELECTROPHOTOLUMINESCENCE OF CHLOROPLASTS |
| |
Authors: | James L Ellenson Kenneth Sauer |
| |
Institution: | Chemistry Department and Laboratory of Chemical Biodynamics, University of California, Berkeley. CA 94720, U.S.A. |
| |
Abstract: | Abstract— Delayed light emission emanating from preilluminated chloroplasts can be perturbed with pulsed DC electric fields (200–4000 V cm-1), The perturbation produces a strong stimulation of chlorophyll luminescence. During the field perturbation the stimulated emission rises to a maximum, typically within 100μs. and then decays. Two kinetic components, R (rapid) and S (slow)†, are distinguished on the basis of their rise and decay times and their field-dependence. The R component increases exponentially at high fields, decays within 100–300μs during the field pulse and collapses with t 1/2= 15 μs at the end of the field pulse. The S component occurs at low fields, exhibits near saturation at 500 V cm-1, decays with t 1/2 about 3 ms during the field pulse, and collapses with t 1/2= 38μs at the end of the field pulse. Studies using inhibitors, ionophores, electron donors and electron acceptors associate the R component with ion transport processes. The relation to electron transport associated with Photosystem II is discussed. |
| |
Keywords: | |
|
|