Fig. 2

Comparison of low-temperature swelling and subsequent gelatinization behavior of transgenic variants of poplar with and without catalytic delignification. a Cotton linter cellulose (control) and milled wood particles from WT poplar (Populus tremula × P. alba cv. INRA 717-1B4) and three transgenic variants representing high S-lignin (pAtC4H:AtF5H1-35), high G-lignin (pAtC4H:PtF5H2 RNAi) and high OH-G-lignin (p35S:PtCOMTa RNAi) compositions were swollen in two volumes of ice-cold TFA and incubated at –20°C for 15 h. Some samples were subsequently heated to 55°C for 5 h to gelatinize the swollen cellulose. Absolute ethanol was added to 80% (v/v), and insoluble material pelleted by centrifugation. Upper panels: Color of the TFA-soluble extract in 80% ethanol (v/v). Lower panels: After washing in 80% (v/v) ethanol in water, and water alone, the insoluble materials were homogenized and settled in the bottom of 15-ml conical tubes. b Weight % of Xyl and Glu recovered in the soluble fractions from TFA-swollen and gelatinized materials. Values are the means ± S.D. of three determinations