Multiple stress factors and the emission of plant VOCs.

Individual biotic and abiotic stresses, such as high temperature, high light and herbivore attack, are well known to increase the emission of volatile organic compounds from plants. Much less is known about the effect of multiple, co-occurring stress factors, despite the fact that multiple stresses are probably the rule under natural conditions. Here, after briefly summarizing the basic effects of single stress factors on the volatile emission of plants, we survey the influence of multiple stresses. When two or more stresses co-occur their effects are sometimes additive, while in other cases the influence of one stress has priority. Further investigations on the effects of multiple stress factors will improve our understanding of the patterns and functions of plant volatile emission.