Phenotypic analysis of 35S:MIR857 plants. A, Six-week-old plants of the wild type (WT) and 35S:MIR857. B and C, 3D-μCT image of stem cross sections of wild-type and 35S:MIR857 plants. ixf, Interfascicular xylem fibers; xv, xylem. Scale bar = 100 μm. D,) Relative AtLAC7 mRNA levels in wild-type and 35S:MIR857 plants as measured by qRT-PCR. E, Quantification of laccase activity in partially purified protein extracts, with 2,2′-azinobis-3-ethylbenzthiazolinesulfonic acid (ABTS) as the substrate. Data represent means ± sd (n = 6). F to I, Quantitative analysis of plant height, tensile strength of the stem, stem fresh biomass, and average stem diameter in 6-week-old wild type and 35S:MIR857. Data represent means ± sd (n = 17). *, 0.01 < P < 0.05.