Effects of Altered Gravity Conditions on Lignin and Secondary Wall Formation in Herbaceous Dicots and Woody Plants

Abstract

A relationship between lignin formation and gravity is important in biological development of plants in space, because lignin is considered to have played one of the most important roles in the evolution of land plants. This relationship has been studied from a basic biological point of view in herbaceous plants. On the other hand, this relationship is mainly focused on formation of reaction wood in woody plants and has been studied from a practical point of view because of deleterious features of reaction wood for wood manufacture. The International Space Station (ISS) is currently in operation and unique space exp e rime nts are to b e performed using both herbaceous and woody plants. Recent advances in the study of roles of gravity on lignin and secondary wall formation are reviewed.

Involvement of auxin dynamics in hypergravity-induced promotion of lignin-related gene expression in Arabidopsis inflorescence stems

“…In addition, microarray analysis showed that hypergravity up-regulated genes responsible for the biosynthesis or modification of secondary cell wall components such as lignin ( Tamaoki et al , 2009 ). These facts indicate that regulation of lignin formation in response to hypergravity is mediated through the transcriptional regulation of genes related to lignin formation ( Karahara et al, 2009 ).…”

Role of the Cell Wall-Sustaining System in Gravity Resistance in Plants

“…Thus, xyloglucans and 1,3,1,4-β-glucans appear to act as anti-gravitational cell wall polysaccharides. In addition, cellulose and lignin play a role in gravity resistance (Hoson, 2009;Karahara et al, 2009;Wakabayashi et al, 2009a, b). Taken together, these results show that plants increase the rigidity of their cell walls via modifications to the metabolism as the final step in gravity resistance Hoson et al, 2005;Hoson, 2006).…”