Figure 1.
Total VOC emissions (mean ±1SE) from naturally endophyte free (E-; circles) vs infected (E+; triangles) tall fescue (a) and meadow fescue (b) in response to aphid or mechanical damage.
C: untreated control; W: mechanical wounding; A: aphid infestation. For comparison, manipulatively endophyte free tall fescue (ME-; squares) was included. All damage treatments were initiated at the same time, then VOC collections conducted at 1 day after mechanical wounding, or at 6 and 12 days after aphid addition. Statistical details are shown in tables 1 and 2.
Figure 2.
Individual VOCs of tall fescue whose release changed significantly in response to endophyte infection and 12 days of aphid feeding.
E-: naturally endophyte free; E+: naturally endophyte infected; ME-: manipulatively endophyte free; C: untreated control; A: aphid damage. Statistical details are shown table S1.
Table 1.
Summary of LMM results showing the level of significance for the effect of endophyte (E), aphid (A) and sampling time (T) on VOC emissions of tall fescue.
Figure 3.
Individual VOCs of meadow fescue which changed significantly in response to endophyte infection and 12 days of aphid feeding.
E-: naturally endophyte free; E+: naturally endophyte infected; C: untreated control; A: aphid damage. Statistical details are shown table S5.
Table 2.
Summary of LMM results showing the level of significance for the effect of endophyte (E), aphid (A) and sampling time (T) on VOC emissions of meadow fescue.
Figure 4.
PLS-DA plots based on comparisons among VOC blends emitted by differently treated plants at 12 days after aphid addition.
E-: naturally endophyte free; E+: naturally endophyte infected; ME-: manipulatively endophyte free; C: control; A: aphid feeding. For tall fescue (upper panel), a clear separation was seen between control and infested plants, which clustered mainly on the right and left side of the plot, respectively, whereas plants of different endophyte status within each damage treatment largely overlapped. For meadow fescue (lower panel), E- and E+ plants grouped separately while overlapping somewhat, with the strongest separation occurring between infested E- plants and any other treatment. Statistical details concerning compounds responsible for the clustering are given in tables S1 and S5.