Sensitivity of wild and domesticated Rhododendron chrysanthum to different light regime (UVA, UVB, and PAR)

Abstract

Effects of UV radiation on photosynthetic capacity of wild and domesticated Rhododendron chrysanthum were compared by applying PAR (P), P + UVA (PA), and P + UVA + UVB (PAB) radiation for 3 d, respectively. Results showed that photosynthetic activity of two R. chrysanthum types was not affected by UVA but inhibited by UVB, and the inhibitory effects of UVB were dose-dependent. Changes in nonphotochemical quenching suggest that the range of photosynthetic capacity is ranked as follows: 24-48 h of UVB dose < wild type < 72 h of UVB dose < domesticated type, indicating that the wild type initiated photoprotective function in response to UVB stress due to its lower photosynthetic capacity, while domesticated type did not due to its higher photosynthetic capacity. Taken all the given data together, the wild type was more sensitive to UV stress, but it showed more effective mechanisms of counteracting it.