Reaction Wood Anatomy in a Vessel-Less Angiosperm Sarcandra Glabra

Abstract

Anatomy and lignin distribution in artificially inclined stems of Sarcandra glabra were investigated to clarify the characteristics of reaction wood (RW) in a vessel-less angiosperm species. Of the five coppiced stems studied from a single tree, two stems were fixed straight and classified as normal wood (NW) and the remaining three stems were inclined at 50 degrees from the vertical to induce the formation of the RW. Compared with NW, the lower side of the inclined samples had a relatively high compressive surface-released strain and an increase in the microfibril angle of the S2 layer of tracheids. However, no significant change was observed in the length or cell wall thickness of the tracheids. The results of Wiesner and Mäule colour reactions indicated that the amount of guaiacyl lignin in the cell walls of tracheids was increased in RW. It appears that RW in Sarcandra is formed on the lower side of inclined stems, and its anatomical characteristics and chemical composition are similar to those of the compression wood (CW) found in gymnosperm species (the so-called “CW-like RW” type).