Photoprotection Strategies in Young Leaves of Dominant Species in Mid- and Late-Successional Stages of Low Subtropical Forest in Winter

Abstract:

In order to understand the mechanism of photoprotection strategies of dominant species at different successional stages under different light environments in winter, the physiological and biochemical responsethree dominant species at mid-successional stage, i.e. Schima superba, Castanopsis chinensis and Castanopsis fissa and three dominant species at late-successional stage, i.e. Machilus chinensis, Cryptocarya coninna, Cryptocarya chinensis grown on full light (100% natural light) and low light (30% natural light) were studied. The results showed that, compared with full light, the non-photochemical quenching (NPQ), ratio of carotenoid to chlorophyll (Car/Chl) and anthocyanin content in young leaves of dominant species at mid-successional stage under low light decreased, and the relative cytoplasmic membrane leakage increased. On the contrary, the anthocyanin content in young leaves of dominant species in the late-successional stage increased, the relative cytoplasmic membrane leakage decreased, and the degree of light inhibition was low (high F_v/F_m). In addition, the anthocyanin content, NPQ and Car/Chl in young leaves of mid-successional species were significantly lower than those of late- successional species except of total antioxidant capacity. So, the dominant species at late-successional stage could improve their adaptability to high light environments in winter through their flexible light protection strategies. However, the diversity of light protection strategies and light protection ability of dominant species at mid- successional stage were weaker than those at late-successional stage.