Effects of Fluoride Stress on Chlorophyll Fluorescence in Leaves of Tea Seedlings

Abstract:

The objective was to understand the effect of fluoride (F) stress on chlorophyll fluorescence in tea [Camellia sinensis (L.) O. Kuntze ‘Ruixiang’] leaves. Tea seedlings at 10-month-old grown in pots were fertilized with NaF three times weekly for 6 weeks. The results showed that O phase in OJIP curve rose a little treated with 600 mg L^-1 NaF, and P phase and IP phase decreased obviously, L-step at about 150 μs and K-step at about 300 μs appeared. Under F stress, the fluorescence parameters, such as RC/CS_o, ET_o/ABS, RE_o/ET_o, RE_o/ABS, PI_abs and PI_cs decreased in tea leaves, while V_J, V_I, DI_o/RC, DI_o/CS_o, DI_o/ABS and dissipated energy increased. There were negative correlations between F content in tea leaves and ET_o/TR_o, RE_o/ABS and PI_CS, but a positive correlation with DI_o/RC. Therefore, the ability of photosynthetic electron transfer in tea leaves was weakened under F stress, the whole electron transport chain from PSII to PSI was affected, meanwhile, leaves could prevent light suppression and light damage by increasing heat dissipation itself.