DOI: 10.5061/dryad.gf1vhhmvx
title: Nutrient conditions mediate mycorrhizal effects on biomass production and cell wall chemistry in poplar

description:  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.
description: 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. 
description: # Nutrient conditions mediate mycorrhizal effects on biomass production
 and cell wall chemistry in poplar
 [https://doi.org/10.5061/dryad.gf1vhhmvx](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 cm<sup>3</sup> wood.den = estimated wood density at the time of harvest in g cm<sup>-3</sup> 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.