Tuittila, E.-S. | bioRxiv Science

bioRxiv2023

CH4 transport in wetland plants under controlled environmental conditions: untangling the impacts of phenology

O_LIMethane (CH4) fluxes at plant surfaces are the net result of transport of soil-produced CH4 and within-plant CH4 production and consumption, yet factors and processes controlling these fluxes remain unclear. C_LIO_LIWe conducted high-frequency automated CH4 flux measurements from shoots of Carex rostrata (sedge), Menyanthes trifoliata (forb) and shrubs (Betula nana, Salix lapponum) during early, high and late summer in a climate-controlled environment to assess the effects of environmental variables, seasonality and CH4 cycling microbes in the CH4 flux. Measurements were conducted from intact plant-soil samples collected throughout growing seasons 2020 and 2021 from Lompolojankkafen, northern Finland. C_LIO_LIAll studied species showed seasonal variability in CH4 fluxes. The CH4 fluxes were not impacted by light level, while out of the studied species, porewater CH4 concentration increased fluxes from all but B. nana. Air temperature only and negatively affected CH4 flux from C. rostrata. Both methanogens and methanotrophs were detected in aboveground parts of S. lapponum and M. trifoliata, methanotrophs in B. nana, while neither were detected in C. rostrata. C_LIO_LIOur study demonstrates that the seasonal phase of the plants regulates CH4 flux they mediate across species, which was not observed in the field. The detection of methanogens and methanotrophs in herbs and shrubs suggests that microbial processes may contribute to their CH4 flux. C_LI

ecology↗

bioRxiv2020

Morphological and biochemical responses of Sphagnum mosses to environmental changes

* Background and AimsSphagnum mosses are vital for peatland carbon (C) sequestration, although vulnerable to environmental changes. For averting environmental stresses such as hydrological changes, Sphagnum mosses developed an array of morphological and anatomical peculiarities maximizing their water holding capacity. They also produce plethora of biochemicals that could prevent stresses-induced cell-damages but these chemicals remain poorly studied. We aimed to study how various anatomical, metabolites, and antioxidant enzymes vary according to Sphagnum taxonomy, phylogeny and environmental conditions. * MethodsWe conducted our study in five Sphagnum-dominated peatlands distributed along a latitudinal gradient in Europe, representing a range of local environmental and climate conditions. We examined the direct and indirect effects of latitudinal changes in climate and vegetation species turnover on Sphagnum anatomical (cellular and morphological characteristics) and biochemical (spectroscopical identification of primary and specialized metabolites, pigments and enzymatic activities) traits. * Key resultsWe show that Sphagnum traits were not driven by phylogeny, suggesting that taxonomy and/or environmental conditions prevail on phylogeny in driving Sphagnum traits variability. We found that moisture conditions were important determinants of Sphagnum anatomical traits, especially those related to water holding capacity. However, the species with the highest water holding capacity also exhibited the highest antioxidant capacity, as showed by the high flavonoid and enzymatic activities in their tissues. Our study further highlighted the importance of vascular plants in driving Sphagnum biochemical traits. More particularly, we found that Sphagnum mosses raises the production of specific compounds such as tannins and polyphenols known to reduce vascular plant capacity when herbaceous cover increases. * ConclusionsOur findings show that Sphagnum anatomical and biochemical traits underpin Sphagnum niche differentiation through their role in specialization towards biotic stressors, such as plant competitors, and abiotic stressors, such as hydrological changes, which are important factors governing Sphagnum growth.

ecology↗