Cell wall adaptations to multiple environmental stresses in maize roots

Abstract

A municipal solid-waste bottom slag was used to grow maize plants under various abiotic stresses (high pH, high salt and high heavy metal content) and to analyse the structural and chemical adaptations of the cell walls of various root tissues. When compared with roots of control plants, more intensive wall thickenings were detected in the inner tangential wall of the endodermis. In addition, phi thickenings in the rhizodermis in the oldest part of the seminal root were induced when plants were grown in the slag. The role of the phi thickenings may not be a barrier for solutes as an apoplastic dye could freely diffuse through them. The chemical composition of cell walls from endodermis and hypodermis was analysed. Slag-grown plants had higher amounts of lignin in endodermal cell walls when compared to control plants and a higher proportion of H-type lignin in the cell walls of the hypodermis. Finally, the amount of aliphatic suberin in both endo- and hypodermal cell walls was not affected by growing the plants on slag. The role of these changes in relation to the increase in mechanical strengthening of the root is discussed.

Chromium immobilization by extra- and intraradical fungal structures of arbuscular mycorrhizal symbioses

“…This indicates that the fungal structures together with cell walls in mycorrhizal roots could accumulate Cr, and restrain Cr translocation to plant cytoplasm. The restrain of heavy metals by plant cell walls is a common way plant relieve metal toxicity, which has also been reported in many previous studies [56][57][58][59]. The highly accumulated Cr in the intraradical fungal structures may result from Cr uptake and transport to mycorrhizal roots by the extraradical mycelium [20,21,60], or from Cr transport to the intraradical fungal structures from plant cells that take up Cr directly from the environment.…”

Efeitos dos rejeitos da indústria de zinco na anatomia e crescimento de plantas jovens de Salix humboldtiana Willd: (salgueiro)

“…No caso de estresse por metais pesados no solo, o sistema radicular é particularmente afetado por ser a parte da planta em contato direto com o contaminante (Degenhardt & Gimmler 2000). Alguns estudos têm mostrado alterações na arquitetura e estrutura de raiz induzida por uma variedade de condições estressantes, tais como salinidade e metais pesados (Reinhardt & Roswt 1995, Lux et al 2004), e também alterações nas barreiras apoplásticas (Perumalla & Peterson 1986, North & Nobel 1995.…”

Progressive Inhibition by Water Deficit of Cell Wall Extensibility and Growth along the Elongation Zone of Maize Roots Is Related to Increased Lignin Metabolism and Progressive Stelar Accumulation of Wall Phenolics

“…Several reports suggest that cell wall binding of phenolic substances, for example as oxidatively linked Tyr bridges between wall structural proteins, di or tri ferulic ester bridges between wall arabinoxylan polymers, or as more complex lignin polymer deposits, may be associated with wall stiffening during cell maturation (e.g. Fry, 1979Fry, , 1986Kamisaka et al, 1990;Ralph et al, 1995;Carpita, 1996;Degenhardt and Gimmler, 2000;Schopfer et al, 2001;MacAdam and Grabber, 2002;Boerjan et al, 2003;Jung, 2003;Fry, 2004). However, the hypothesis that progressive inhibition by water deficit of wall extensibility and segmental growth rates in the root elongation zone may be related to spatially localized and progressive alterations in patterns of wall-phenolic accumulation, does not appear to have been previously investigated.…”