Effects of enhanced UV-B radiation on plant physiology and growth on the Tibetan Plateau: a meta-analysis

Uncertainties about the response of plant physiology and growth to enhanced UV-B radiation cause uncertainty to predict how plant production will vary under future radiation change on the Tibetan Plateau. Here, we used a meta-analysis approach to test the influence of UV-B radiation on plant physiology and growth. This hypothesis was tested by investigating the response of plants, which was expressed by some measurable variables. Enhanced UV-B radiation decreased plant biomass, plant height, basal diameter, leaf area index, maximal PSII efficiency, and Chl a+b, but increased intercellular CO2 concentration, malondialdehyde (MDA), hydrogen peroxide, superoxide anion radical, peroxidase, ascorbate peroxidase, proline and UV-B absorbing compounds. The effect of enhanced UV-B radiation on net photosynthesis rate (P-n) increased with mean annual precipitation and experimental duration. The effect of enhanced UV-B radiation on MDA decreased with experimental duration. The effect of enhanced UV-B radiation on superoxide dismutase (SOD) increased with the magnitude of enhanced UV-B radiation. Forests rather than grasslands exhibited a positive response of SOD and a negative response of P-n to enhanced UV-B radiation. Therefore, the effect of enhanced UV-B radiation on alpine plants varied with ecosystem types. Local climate conditions may regulate effects of enhanced UV-B radiation on alpine plants.