Amino acid-mediated impacts of elevated carbon dioxide and simulated root herbivory on aphids are neutralized by increased air temperatures.
Bottom Line: Root damage reduced aboveground biomass, height, and root %N, and increased root %C and C:N, most probably via decreased biological nitrogen fixation.Total foliar amino acid concentrations and aphid colonization success were higher in plants with roots cut early (before aphid arrival) than those with roots cut late (after aphid arrival); however, this effect was counteracted by eT.These results demonstrate the importance of amino acid concentrations for aphids and identify individual amino acids as being potential factors underpinning aphid responses to eT, eCO2, and root damage in lucerne.
Affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia J.Ryalls@uws.edu.au.Show MeSH
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Mentions: Plant-damage treatment also significantly affected total amino acids (F1,287=3.042; P=0.011). but had no effect on essential amino acids. On plants without aphids present, total amino acid concentrations were greater in roots that were cut early compared with those cut late, although neither early- or late-cut plants were significantly different from uncut controls, which contained intermediate concentrations. When aphids were present, amino acid concentrations were generally higher, but no significant root-damage effects were detected. However, late-cut plants with aphids contained significantly higher concentrations of amino acids than late-cut plants without aphids (Fig. 5). Similar to individual models (Table 1), glutamic acid and group 2 amino acids were significantly affected by plant-damage treatment (Supplementary Table S2 at JXB online). Group 2 amino acids showed dramatic increases in late-cut plants when aphids were present (Supplementary Fig. S2D).
Affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia J.Ryalls@uws.edu.au.