Test for Photosystem II protection from UV radiation
To test the hypothesis that UV filtering would increase vulnerability to UV damage at PSII, desiccated samples were also subjected to a laboratory UV treatment, and Fv/Fm and ΦPSII were measured during simulated winter recovery conditions. There were no significant differences inF v/F m within each treatment group (UV-filtered, UV-transmitted, and site reference) at T0 and T192 after the laboratory UV treatment (Figure S2). At T24, UV-transmitted field plants that received a laboratory UV treatment had significantly higherF v/F m than UV-transmitted that did not. Similarly, ΦPSII of each treatment group was not significantly different after the laboratory UV treatment at T0 and T192, but at T24was significantly higher in laboratory UV-treated UV-transmitted samples than UV-transmitted with no laboratory UV treatment (Figure S3).