Role of the plant cell wall in gravity resistance

Abstract

Gravity resistance, mechanical resistance to the gravitational force, is a principal graviresponse in plants, comparable to gravitropism. The cell wall is responsible for the final step of gravity resistance. The gravity signal increases the rigidity of the cell wall via the accumulation of its constituents, polymerization of certain matrix polysaccharides due to the suppression of breakdown, stimulation of cross-link formation, and modifications to the wall environment, in a wide range of situations from microgravity in space to hypergravity. Plants thus develop a tough body to resist the gravitational force via an increase in cell wall rigidity and the modification of growth anisotropy. The development of gravity resistance mechanisms has played an important role in the acquisition of responses to various mechanical stresses and the evolution of land plants.

A hypergravity environment increases chloroplast size, photosynthesis, and plant growth in the moss Physcomitrella patens

“…Among these environmental changes, the effects of gravity on land may undoubtedly have induced alterations in the physiology, anatomy, and growth of bryophytes, extrapolated from previous findings obtained from vascular plants. Gravity influences the physiological processes of vascular plants including long-distance water transport (Lambers et al 2008), leaf gas exchange (Hirai and Kitaya 2009), cell proliferation (Matía et al 2010), and cell wall rigidity (Hoson and Wakabayashi 2015) and, thus, plant growth (Hangarter 1997). Nevertheless, few studies have investigated the gravitational responses of bryophytes even though gravitropism has been extensively examined (Banbury 1962; Cove and Quatrano 2006; Martin et al 2009; Repp et al 2004; Schwuchow et al 2002); only one study showed the significant effect of microgravity on the growth pattern of the dark-grown protonemata of the moss Ceratodon purpureus (Kern et al 2005).…”

Enhancement of biologically active compounds in germinated brown rice and the effect of sun-drying

“…These outcomes evidence the accumulation of γoryzanol derivatives during drying under solar exposition that can be attributed to the sunlight effect on ferulic acid metabolism and further synthesis of individual γ-oryzanol components. It has been reported that sunlight has a profound effect on the biosynthesis of ferulic acid esters by affecting the metabolic activation of enzymes involved in the defence mechanism to radiation (Wang et al, 2014), and also in the development of new plant structural tissues (Hoson and Wakabayashi, 2015). To our knowledge, this is the first report describing the effect of sun-drying on γ-oryzanol content and composition evidencing GBR as a rich source of γ-oryzanol.…”

The effect of lunisolar tidal acceleration on stem elongation growth, nutations and leaf movements in peppermint (Mentha × piperita L.)

“…10 3 Gal is the Earthly gravitational acceleration (Zharkov ), are, in practice, of no significance for living process, including those of plants. However, this view hardly takes account of anything other than the superficial appearance of biological organisms, all of which are constructed in such a way that they actually resist physical forces such as gravity (Hoson & Wakabayashi ), as well as exposure to varying atmospheric and hydrostatic pressures.…”