Nutrient conditions mediate mycorrhizal effects on biomass production and cell wall chemistry in poplar
Data files
Oct 19, 2023 version files 24.47 KB
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PoplarGrowth.csv
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PoplarSCW.csv
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README.md
Abstract
Large-scale biofuel production from lignocellulosic feedstock is limited by the financial and environmental costs associated with growing and processing lignocellulosic material and the resilience of these plants to environmental stress. Symbiotic associations with arbuscular (AM) and ectomycorrhizal (EM) fungi represent a potential strategy for expanding feedstock production while reducing nutrient inputs. Comparing AM and EM effects on wood production and chemical composition is a necessary step in developing biofuel feedstocks. Here, we assessed the productivity, biomass allocation and secondary cell wall (SCW) composition of greenhouse-grown Populus tremuloidesMichx. inoculated with either AM or EM fungi. Given the long-term goal of reducing nutrient inputs for biofuel production, we further tested the effects of nutrient availability and nitrogen: phosphorus stoichiometry on mycorrhizal responses. Associations with both AM and EM fungi increased plant biomass by 14–74% depending on the nutrient conditions but had minimal effects on SCW composition. Mycorrhizal plants, especially those inoculated with EM fungi, also allocated a greater portion of their biomass to roots, which could be beneficial in the field where plants are likely to experience both water and nutrient stress. Leaf nutrient content was weakly but positively correlated with wood production in mycorrhizal plants. Surprisingly, phosphorus played a larger role in EM plants compared with AM plants. Relative nitrogen and phosphorus availability were correlated with shifts in SCW composition. For AM associations, the benefit of increased wood biomass may be partially offset by increased lignin content, a trait that affects downstream processing of lignocellulosic tissue for biofuels. By comparing AM and EM effects on the productivity and chemical composition of lignocellulosic tissue, this work links broad functional diversity in mycorrhizal associations to key biofuel traits and highlights the importance of considering both biotic and abiotic factors when developing strategies for sustainable biofuel production.
README: Nutrient conditions mediate mycorrhizal effects on biomass production and cell wall chemistry in poplar
https://doi.org/10.5061/dryad.gf1vhhmvx
Two .csv files contain raw and calculated data each row is a replicate plant from a mycorrhizal by nutrient treatment.
Description of the data and file structure
Headers in the "PoplarGrowth.csv" file are as follows:
fert.trt = categorical nutrient treatment coded as 1-4
fert.strength = strength of fertilizer application coded as 100% (high) or 15% (low)
fertN = nitrogen content of the fertilizer in ppm
fertP = phosphorus content of the fertilizer in ppm
fertNP = nitrogen to phosophorus ratio of the nutrient treatment
myc = categorical mycorrhizal treatment coded as A = arbuscular, E = ectomycorrhizal and C = nonmycorrhizal control
rep = plant replicate ID
ht.cm = plant height at the time of harvest in cm
dia.cm = basal stem diameter at the time of harvest in cm
stem.vol.cm3 = estimated stem volume at the time of harvest in cm3
wood.den = estimated wood density at the time of harvest in g cm-3
totalbio.g = total plant biomass at the time of harvest in g
rootbio.g = root biomass at the time of harvest in g
leafbio.g = leaf biomass at the time of harvest in g
stembio.g = stem biomass at the time of harvest in g
RMF = root mass fraction calculated as root biomass / total biomass
LMF = leaf mass fraction calculated as leaf biomass / total biomass
SMF = stem mass fraction calculated as stem biomass / total biomass
leafN = leaf nitrogen content at the time of harvest in %
leafP = leaf phosphorus content at the time of harvest in %
AMcol = proportion of root length colonized by arbuscular mycorrhizal fungi at the time of harvest in %
EMcol = proportion of root tips colonized by ectomycorrhizal fungi at the time of harvest in %
Headers in the "PoplarSCW.csv" file are as follows:
fert.trt = categorical nutrient treatment coded as 1-4
fert.strength = strength of fertilizer application coded as 100% (high) or 15% (low)
fertN = nitrogen content of the fertilizer in ppm
fertP = phosphorus content of the fertilizer in ppm
fertNP = nitrogen to phosophorus ratio of the nutrient treatment
myc = categorical mycorrhizal treatment coded as A = arbuscular, E = ectomycorrhizal and C = nonmycorrhizal control
rep = plant replicate ID
total.lig = total lignin content at the time of harvest in %
klas.lig = total insoluble (klas) lignin content at the time of harvest in %
sol.lig = total soluble lignin content at the time of harvest in %
total.sugar = total sugar content at the time of harvest in %
total.hemi = total hemicellulose content at the time of harvest in %
ara = arabinose content at the time of harvest in %
gal = galactose content at the time of harvest in %
glu = glucose content at the time of harvest in % (used as proxy for cellulose content)
xyl = xylose content at the time of harvest in %
man = mannose content at the time of harvest in %
lig.cel.ratio = ratio of ligin to cellulose content at the time of harvest
hemi.cel.ratio = ratio of hemicellulose to cellulose content at the time of harvest
Please note that "NA" indicates that data were not observed for that replicate.
Methods
To test the effects of mycorrhizal fungi on poplar traits, we inoculated Populus tremuloides with multi-species consortiums of arbuscular and ectomycorrhizal fungi. Nonmycorrhizal plants were included as a control. Plants were grown in a greenhouse under varying nutrient conditions by applying 100% (high) and 15% (low) strength Hoaglands solution modified to a 3:1 or 9:1 nitrogen to phosphorus ratio. Plants were harvested nine weeks after the start of the nutrient treatments and separated into leaf, stem, and root tissue to determine biomass. Allocation to different plant tissues was calculated as the ratio of tissue-specific biomass relative to total plant biomass (leaf mass fraction, LMF = dry leaf biomass / total dry biomass; stem mass fraction, SMF = dry stem biomass / total dry biomass; root mass fraction, RMF = dry root biomass / total dry biomass). Stem height and basal diameter were to estimate total stem volume and wood density (density = stem biomass/stem volume). Leaf nitrogen content was analyzed by flash combustion on a NC Elemental Analyzer. Leaf phosphorus content was analyzed by colorimetric analysis. A subset of plants from each mycorrhizal and nutrient treatment were used to analyze secondary cell wall composition. After removing the bark, stem sections were depithed, ground, and processed as follows. Nonstructural compounds were removed by acetone extraction and treatment with sulfuric acid. Insoluble lignin fractions were determined gravimetrically. Acid-soluble lignin was determined by reading the absorbance of the hydrolysate. Structural carbohydrate composition was determined through ion-exchange chromatography.