Effects of potassium deficiency on chlorophyll fluorescence in leaves of tea seedlings

The objective was to determine the mechanism of the alteration of photosynthetic electron transport, light energy transformation and utilization of tea tree leaves under K deficiency. Vegetative propagated 10-month-old tea Camellia sinensis (L.) O. Kuntze cv. Ruixiang seedlings grown in pots were fertilized three times weekly for 24 weeks with different nutrient solution contents, 0, 100, 200, 600 and 2000 mol/L potassium. The results show that OJIP transients from the K-deficiency leaves display the decreased P-step and the increased O-step, and as well as two new steps at about 150 s (L-step) and 300 s (K-step) in the different spectra compared with the control. The RC/CSo, TRo/ABS (or Fv/Fm), ETo/ABS, REo/ABS, PIabs and PIcs are decreased in the K-deficiency leaves, while VJ, VI and dissipated energy are increased. In conclusion, The K deficiency decreases photosynthetic electron transport capacity by impairing the whole electron transport chain from PSII donor side up to the PSI. Enhanced energy dissipation protects the leaves of K-deficiency plants from photo-oxidative damage in high light.