| Abstract: | The objective of this study was to determine the regulation effects of He-Ne laser on protein metabolism, photosynthesis of Isatis indigotica seedlings exposed to enhanced ultraviolet-B (UV-B) lesions. The Isatis indigotica seedlings were subjected to UV-B radiation (10.08kJ·m-2) for 8h·day-1 for 8 days under photosynthetically active radiation (220μ mol·m-2·s-1) and then exposed to laser radiation (633nm; 5.23mW.mm-2; beam diameter: 1.5mm) for 5min each day without ambient light radiation. Changes in a number of protein metabolism parameters, photosynthesis parameters and biomass were measured and used as indicators of the regulation capacity of laser radiation on UV-B lesions. The results revealed that laser has up-regulation effects on the protein metabolism, photosynthesis and biomass of seedlings exposed to elevated UV-B lesions by enhancing the activities of proteinase, alanine aninotransferase (ALT), aspartate aninotransferase (AST), the concentrations of soluble protein, dissociative amino acid, the CPD concentration and chlorophyll, the net photosynthesis (Pn), the stomatal conductance (Gs) and the biomass accumulation. These results suggested that laser radiation could retard leaf senescence induced by UV-B and up-regulate the seedling growth of UV-B-induced lesions. |
