Alleviation of high light stress in shade-treated tea leaves by acclimation to light before shade removal.

Shade cultivation of tea plants (Camellia sinensis L.) is employed for the production of high-quality green tea which increases the content of chlorophylls and free amino acids, including theanine. However, shaded tea plants suffer from photooxidative stress caused by sudden exposure to high light (HL) when the shade is removed. In this study, we tried to acclimatize shaded tea plants to light prior to shade removal to alleviate HL-induced stress. Acclimated tea plants showed milder photoinhibition in response to HL exposure than the shaded plants without acclimation. Moreover, there were no large differences in the total chlorophylls and free amino acids (including theanine) content between acclimated and non-acclimated plants. These results indicate that acclimation of shaded tea plants can alleviate subsequent HL stress without causing large changes in the content of chemical components associated with tea quality.