Fig. 3. Length, dry weight, and dry weight/length ratio of the seventh internode of sunflower plants as affected by sunlight [control, red light/far-red light (R/FR) = 1.1] or low R/FR ratios (0.3) reaching the stem, and normal or reduced (40%) PAR reaching the whole shoot. The internode was harvested after reaching its maximum length. Bars indicate standard errors and the results of two-way ANOVA are shown (NS, not significant at the 0.05 level).