The impacts of phosphorus deficiency on the photosynthetic electron transport chain (Plant Physiol)

Phosphorus deficiency is widespread and can severely limit plant growth.  Carstensen et al. investigated how P deficiency affects photosynthesis in barley. They compared chlorophyll a fluorescence transients (OJIP transients) between P-deficient, sufficient and resupplied plants. They observed depletion in the I-step associated with P deficiency, which is consistent with an inhibition of electron transport to PSI. Interestingly, infiltration of these leaves with a solution containing P_i led to a recovery of the I-step within an hour. Further, they showed that Pi deficiency led to a decrease in ATP production, leading to acidification of the thylakoid lumen, leading to energy dissipation via non-photochemical quenching and restricted PQH₂ oxidation due to the proton backlog caused by lumen acidification. (Summary by Mary Williams) Plant Physiol. 10.1104/pp.17.01624