Mechanisms by which mycorrhizae and competition altered herbivory
Overall, mycorrhizae decreased plant nutritional quality by 19% (Fig 2,
F1,78=6.40 p < 0.001). Plants inoculated with
mycorrhizae and experiencing competition had 13% lower nutritional
quality (elevated C/N ratios) in response to jasmonic acid induction
(three- way interaction between competition, mycorrhizae and jasmonic
acid induction (Fig. 2, F1,78=5.35, p=0.024). In
contrast, plants grown without mycorrhizae did not respond to JA
induction by altering nutritional quality. The % carbon in the leaf
tissue remained constant across all treatments (Mycorrhizae
F1,45=0.229 p=0.634, Competition
F1,45=1.063 p=0.307, Induction F1,45=
0.017 p=0.898) so the changes in the C/N Ratio was driven by changes to
the percent Nitrogen (df=53, R2=0.930,
p>0.001).