Fig. 5.

Box plots showing emission of acetic acid, acetone, ethanol and methanol during ageing of control seeds of Agrostemma githago (a), Lolium perenne (b), Pisum sativum (c). White boxes represent seeds with > 85% total germination (> 70% for Lolium perenne), and grey boxes represent seeds with < 85% total germination (< 70% for Lolium perenne). The boxes span the 25^th to 75^th percentiles, with the median and mean represented by a line and square, respectively. Whiskers show the minimum and maximum values. Asterisks indicate significant differences (*, P < 0.05; **, P < 0.01; ***, P < 0.001) in the emission of individual volatiles from seeds with high (> 85% or 70%) and low (< 85% or 70%) germination determined using a two-sample, two-tailed t-test