Abstract
Plants have mechanisms to alleviate its photoinhibition, for examples, heat-dissipation system as observed in NPQ and electron sinks such as photorespiration and WWC. We found a new system to contribute to the protection of PSII from its inhibition.
Low-light grown tobacco plants (LL-plants) were exposed to high-light conditions. The acclimated plants (LH-plants) were back to low-light conditions (LHL-plants)
Both LH- and LHL-plants showed higher values of NPQ and qP against photosynthetic linear electron flow, compared to LL-plants. The increase in qP, PQ oxidation, did not depend on electron sink activity. The increase in only 15% of qP was due to the increase in NPQ. Thylakoid membranes from LH-plants had a tolerance against photoinhibition of PSII, compared to LL-plants, suggesting a new system, PQ-Oxidation System (POS), which contributes to the alleviation of photodamage and differs from both NPQ and alternative electron sinks, in the acclimation to high light stress.
