Multiple effects of inhibition of mitochondrial alternative oxidase pathway on photosynthetic apparatus in Rumex K-1 leaves

The effects of inhibition of mitochondrial alternative oxidase (AOX) respiratory pathway on photosynthetic apparatus in Rumex K-1 leaves were studied. Under high irradiance, the inhibition of AOX pathway caused over-reduction of photosystem (PS) 2 acceptor side, a decrease in the energy transfer in the PS 2 units, damage of donor side of PS 2 and decrease in pool size of electron acceptors. The inhibition of AOX pathway also decreased photosynthetic performance index (PI_ABS), actual photochemical efficiency (Φ_PS2), photochemical quenching (qP) and photosynthetic O₂ evolution rate. The results demonstrate that mitochondrial AOX pathway plays a vital role in photoprotection of photosynthetic apparatus.