Cell wall lignin content in leaves. The lignin content of untransformed control (WT) and transgenic Vvpgip1 line 37 and 45 is expressed as the percentage contained in the alcohol-insoluble residue (AIR). Lignin content was determined with the acetyl bromide lignin method, as described in . Statistical analyses (two-tailed Student's t-test) could separate the WT from the Vvpgip1 line 37 (p = 0.035) but not Vvpgip1 line 45, for which a similar trend was seen (p = 0.20). Standard deviation is given as error bars. N represents the number of biological repeats.