Silica uptake in aquatic and wetland macrophytes: a strategic choice between silica, lignin and cellulose?

Abstract

*Although silica (Si) is not an essential element for plant growth in the classical sense, evidence points towards its functionality for a better resistance against (a)biotic stress. Recently, it was shown that wetland vegetation has a considerable impact on silica biogeochemistry. However, detailed information on Si uptake in aquatic macrophytes is lacking. *We investigated the biogenic silica (BSi), cellulose and lignin content of 16 aquatic/wetland species along the Biebrza river (Poland) in June 2006 and 2007. The BSi data were correlated with cellulose and lignin concentrations. *Our results show that macrophytes contain significant amounts of BSi: between 2 and 28 mg BSi g(-1). This is in the same order of magnitude as wetland species (especially grasses). Significant antagonistic correlations were found between lignin, cellulose and BSi content. Interestingly, observed patterns were opposite for wetland macrophytes and true aquatic macrophytes. *We conclude that macrophytes have an overlooked but potentially vast storage capacity for Si. Study of their role as temporal silica sinks along the land-ocean continuum is needed. This will further understanding of the role of ecosystems on land ocean transport of this essential nutrient.

The Effects of Silica Fertilizer as an Anti-Herbivore Defense in Cucumber

“…This idea is supported by a comparison study of multiple physical defenses of plants in natural habitats that found higher levels of silica were sometimes associated with higher levels of lignin and cellulose (Schoelynck et al 2010). However, under controlled environmental conditions we found no difference in lignin and less, not more, cellulose in Si+ than Si-plants.…”

Fluxes of water, sediments, and biogeochemical compounds in salt marshes

“…Hackney et al (2000) indicated that high diatom production in tidal marshes and the food web dependent on this production could actually be important contributors to estuarine production (as earlier suggested by Sullivan and Moncreiff 1990). Macrophytes are another factor in autochthonous production of BSi; aquatic and wetland plants can contain significant amounts of BSi (Schoelynck et al 2010). In freshwater marshes, Phragmites australis is particularly rich in BSi (Struyf et al 2007b; up to 5% of the dry biomass in dead reed culms is BSi in saltwater and mesohaline marshes, the dry biomass of Spartina alterniflora and Juncus roemerianus contains up to ±0.5% of BSi (Norris and Hackney 1999;Querné et al 2012).…”

Tracing the origin of dissolved silicon transferred from various soil-plant systems towards rivers: a review

“…The plants need to find a balance between cellulose, lignin and Si incorporation to be rigid but still flexible. Thus, it could be assumed that aquatic macrophyte Si metabolism is closely linked with cellulose and lignin metabolism (Schoelynck et al, 2010).…”