Abstract
Tension wood is formed in the upper side of inclined stem of dicotyledonous woody plants in reaction to a gravitrophic stimulus. G layer, cellulose-rich and non-lignified, occurs in fibers in typical tension wood. We reported that the poplar G layer containinig xyloglucan could incorporate xyloglucan polymer into wall xyloglucans enzymatically. This suggests that specific proteins are expressed to generate tension wood and its stress for upholding the plant. To identify proteins involved in the tension wood production, cell wall proteins were obtained from mature and differentiating xylem of tension and normal wood. They were sequentially extracted with Tris-HCl, 1M NaCl, and detergent/urea solution. Each protein fraction was analyzed with SDS-PAGE and two-dimensional electrophoresis. Proteins increased in the tension wood were further analyzed.
