Abstract
In this study, we evaluated how cadmium inhibitory effect on photosystem II and I electron transport may affect light energy conversion into electron transport by photosystem II. To induce cadmium effect on the photosynthetic apparatus, we exposed Chlamydomonas reinhardtii 24 h to 0-4.62 μM Cd 2+. By evaluating the half time of fluorescence transients O-J-I-P at different temperatures (20-30°C), we were able to determine the photosystem II apparent activation energies for different reduction steps of photosystem II, indicated by the O-J-I-P fluorescence transients. The decrease of the apparent activation energies for PSII electron transport was found to be strongly related to the cadmium-induced inhibition of photosynthetic electron transport. We found a strong correlation between the photosystem II apparent activation energies and photosystem II oxygen evolution rate and photosystem I activity. Different levels of cadmium inhibition at photosystem II water-splitting system and photosystem I activity showed that photosystem II apparent activation energies are strongly dependent to photosystem II donor and acceptor sides. Therefore, the oxido-reduction state of whole photosystem II and I electron transport chain affects the conversion of light energy from antenna complex to photosystem II electron transport.
Original language | English (US) |
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Pages (from-to) | 151-157 |
Number of pages | 7 |
Journal | Photosynthesis research |
Volume | 107 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2011 |
Externally published | Yes |
Keywords
- Activation energy
- Cadmium
- Chlamydomonas reinhardtii
- Oxygen-evolving complex
- Photosystem I
- Photosystem II
ASJC Scopus subject areas
- Biochemistry
- Plant Science
- Cell Biology