HSQC NMR ANALYSIS OF IMMATURE BAMBOO CELL WALLS

摘要

A 6.2 m high immature hachiku bamboo (Phyllostachys nigra Munro var. Henonis) was divided into 7 fractions from bottom to top. Milled bamboo lignin was isolated from both mature bamboo and the basal fraction of the immature bamboo by traditional Bj?rkman method. Acetylated milled bamboo lignin was characterized by ~1H~13 C correlation heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy. In addition to guaiacyl (G) and syringyl (S) lignin signals, p-coumaric acid (pCA) and ferulic acid (FA) signals can also be found in both mature and immature lignin. Furthermore, immature bamboo lignin spectrum has stronger pCA and FA signals than mature bamboo lignin spectrum. The β-aryl ether (β-O-4) structure is clearly discerned in both mature and immature bamboo lignin spectrum. But the phenylcoumaran ((β-5) and resinol (β-β) structures are relatively weak in immature bamboo lignin spectrum. The isolated immature bamboo lignin without purification was associated with arabionxylan. The mature bamboo cell wall regenerated from an ionic liquid was also characterized by HSQC NMR method. The HSQC NMR analysis of isolated lignin and cellwalls would help us better understanding the lignifications of bamboo.