Abstract:
To investigate the roles of the xanthophyll cycle and D1 protein turnover in photoprotection of bamboo, we applied chlorophyll fluorescence techniques to measure the characteristics of photoinhibition in moso bamboo (
Phyllostachys edulis (Carr.) Lehaie) leaves under strong light and xanthophyll cycle inhibitor-dithiothreitol (DTT) and D1 protein synthesis inhibitor-streptomycin sulfate (SM) treatment, respectively. Results showed that the maximum photochemical efficiency (
Fv/
Fm) decreased significantly in leaves of
Ph.
edulis exposed to strong artificial light or strong natural noon light in summer. However, the
Fv/
Fm value could be restored under darkness or in the afternoon under decreased intensity of sunlight. Non-photochemical quenching (NPQ) in
Ph. edulis leaves was inhibited by the DTT and SM treatments, with the inhibition effect of DTT significantly better than that of SM. In addition, the DTT and SM treatments increased the declining degree of chlorophyll fluorescence parameters in
Ph.
edulis leaves under strong light, including
Fv/
Fm, actual photochemical efficiency Y(Ⅱ), and photochemical quenching
qP. These results suggest that
Ph.
edulis leaves possess a complete photoprotection defense mechanism. NPQ is closely associated with the xanthophyll cycle and D1 protein turnover, which plays an important role in
Ph.
edulis photoprotection.