FIGURE 2.

Below and aboveground induced volatile signals released by plants after: A, pathogen attack; B, insect attack; C, mechanical damage; D, touch stress; E, temperature stress; F, air pollutants, G, drought stress; H, salt stress or J, soil microorganisms. Biotic and abiotic stress encountered by plants make them switch to a unique volatile profile and induce the release of specific signals, guiding the receiver to respond in a timely manner to cope with upcoming threat/stress. Simultaneous exposure to the combination of different volatile signals adds to the complexity of plant–plant interactions [Colour figure can be viewed at wileyonlinelibrary.com]