The experimental design was a completely randomized split plot design with two UV-B treatments (main plot) and two cultivars within each treatment as the subplot. Each treatment was replicated twice. Samples were analyzed using the mixed procedure of the Statistical Analysis System (SAS, Cary, NC), with separate models used for the ESS gel data, CPD antibody data, and for the methanol extract absorbance, as each of these used different samples, thus precluding a global multivariate analysis. The models tested for main effects of cultivar, UV-B treatment, sampling day and sampling hour, and their interactions. As several samples were measured on the gel system more than once, a nested term for gel within plant was included in the ESS data analysis. The SAS GLM procedure was used to estimate variance components for the ESS data that contained the nested term.
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