Studies on tree CH4 exchange in boreal forests regarding seasonality and role of tree canopies are rare. We aimed to quantify the contribution of boreal trees to the forest CH4 budget during spring leaf-out and to reveal the role of microbes in the CH4 exchange.
MethodsMethane fluxes of downy birch and Norway spruce (Betula pubescens and Picea abies) growing on fen and upland sites were measured together with soil CH4 flux, environmental variables and microbial abundances involved in the CH4 cycle. Tree CH4 fluxes were studied from three stem heights and from shoots.
ResultsThe trees emitted CH4 with higher stem emissions detected from birch and higher shoot emissions from spruce. The stem CH4 emissions from birches at the fen were high (mean 45\uffc2\uffa0\uffc2\uffb5g\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0h\uffe2\uff88\uff921), decreasing with stem height. Their dynamics followed soil temperature, suggesting the emitted CH4 originated from methanogenic activity, manifested in high mcrA gene copy numbers, in the peat soil. Methanogens were below the quantification limit in the tree tissues. Upscaled tree CH4 emissions accounted for 22% of the total CH4 emissions at the fen.
ConclusionsThe variation in stem CH4 flux between the trees and habitats is high, and the emissions from high-emitting birches increase as the spring proceeds. The lack of detection of methanogens or methanotrophs in the aboveground plant tissues suggests that these microbes did not have a significant role in the observed tree-derived fluxes. The stem-emitted CH4 from birches at the fen is presumably produced microbially in the soil.
", "keywords": ["0301 basic medicine", "570", "550", "Methanogens", "LIVING TREES", "Trees", "03 medical and health sciences", "Methanotrophs", "METHANE EMISSIONS", "SAP FLOW", "Boreal forest", "Waterlogging", "PRECURSOR", "0303 health sciences", "BIOMASS EQUATIONS", "NORWAY SPRUCE", "Forestry", "Methane fux", "15. Life on land", "Environmental sciences", "METHANOTROPHS", "13. Climate action", "RADIATION", "Methane flux", "VEGETATION", "COMMUNITIES"]}, "links": [{"href": "https://link.springer.com/content/pdf/10.1007/s11104-022-05447-9.pdf"}, {"href": "https://doi.org/10.1007/s11104-022-05447-9"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20and%20Soil", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11104-022-05447-9", "name": "item", "description": "10.1007/s11104-022-05447-9", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11104-022-05447-9"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-05-24T00:00:00Z"}}, {"id": "10.1093/jxb/erad014", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-01T16:18:20Z", "type": "Journal Article", "created": "2023-01-11", "title": "Responses of key root traits in the genusOryzato soil flooding mimicked by stagnant, deoxygenated nutrient solution", "description": "AbstractExcess water can induce flooding stress resulting in yield loss, even in wetland crops such as rice (Oryza). However, traits from species of wild Oryza have already been used to improve tolerance to abiotic stress in cultivated rice. This study aimed to establish root responses to sudden soil flooding among eight wild relatives of rice with different habitat preferences benchmarked against three genotypes of O. sativa. Plants were raised hydroponically, mimicking drained or flooded soils, to assess the plasticity of adventitious roots. Traits included were apparent permeance (PA) to O2 of the outer part of the roots, radial water loss, tissue porosity, apoplastic barriers in the exodermis, and root anatomical traits. These were analysed using a plasticity index and hierarchical clustering based on principal component analysis. For example, O. brachyantha, a wetland species, possessed very low tissue porosity compared with other wetland species, whereas dryland species O. latifolia and O. granulata exhibited significantly lower plasticity compared with wetland species and clustered in their own group. Most species clustered according to growing conditions based on PA, radial water loss, root porosity, and key anatomical traits, indicating strong anatomical and physiological responses to sudden soil flooding.
The root barrier to radial O2 loss (ROL) is a trait enabling waterlogging tolerance of plants. The ROL barrier restricts O2 diffusion to the anoxic soil so that O2 is retained inside root tissues.
We hypothesised that the ROL barrier can also restrict radial diffusion of other gases (H2 and water vapour) in rice roots with a barrier to ROL. We used O2 and H2 microsensors to measure ROL and permeability of rice roots, and gravimetric measurements to assess the influence of the ROL barrier on radial water loss (RWL).
The ROL barrier greatly restricted radial diffusion of O2 as well as H2. At 60\uffc2\uffa0kPa pO2, we found no radial diffusion of O2 across the barrier, and for H2 the barrier reduced radial diffusion by 73%. Similarly, RWL was reduced by 93% in roots with a ROL barrier.
Our study showed that the root barrier to ROL not only completely blocks radial O2 diffusion under steep concentration gradients but is also a diffusive barrier to H2 and to water vapour. The strong correlation between ROL and RWL presents a case in which simple measurements of RWL can be used to predict ROL in screening studies with a focus on waterlogging tolerance.
The root barrier to radial O2 loss (ROL) is a trait enabling waterlogging tolerance of plants. The ROL barrier restricts O2 diffusion to the anoxic soil so that O2 is retained inside root tissues.
We hypothesised that the ROL barrier can also restrict radial diffusion of other gases (H2 and water vapour) in rice roots with a barrier to ROL. We used O2 and H2 microsensors to measure ROL and permeability of rice roots, and gravimetric measurements to assess the influence of the ROL barrier on radial water loss (RWL).
The ROL barrier greatly restricted radial diffusion of O2 as well as H2. At 60\uffc2\uffa0kPa pO2, we found no radial diffusion of O2 across the barrier, and for H2 the barrier reduced radial diffusion by 73%. Similarly, RWL was reduced by 93% in roots with a ROL barrier.
Our study showed that the root barrier to ROL not only completely blocks radial O2 diffusion under steep concentration gradients but is also a diffusive barrier to H2 and to water vapour. The strong correlation between ROL and RWL presents a case in which simple measurements of RWL can be used to predict ROL in screening studies with a focus on waterlogging tolerance.
Excess water can induce flooding stress resulting in yield loss, even in wetland crops such as rice (Oryza). However, traits from species of wild Oryza have already been used to improve tolerance to abiotic stress in cultivated rice. This study aimed to establish root responses to sudden soil flooding among eight wild relatives of rice with different habitat preferences benchmarked against three genotypes of O. sativa. Plants were raised hydroponically, mimicking drained or flooded soils, to assess the plasticity of adventitious roots. Traits included were apparent permeance (PA) to O2 of the outer part of the roots, radial water loss, tissue porosity, apoplastic barriers in the exodermis, and root anatomical traits. These were analysed using a plasticity index and hierarchical clustering based on principal component analysis. For example, O. brachyantha, a wetland species, possessed very low tissue porosity compared with other wetland species, whereas dryland species O. latifolia and O. granulata exhibited significantly lower plasticity compared with wetland species and clustered in their own group. Most species clustered according to growing conditions based on PA, radial water loss, root porosity, and key anatomical traits, indicating strong anatomical and physiological responses to sudden soil flooding.