Volatile Signalling Between Plants

In my last post I discussed the underlying theory to plant communication. In this blog I hope to outline a possible signalling mechanisms used in plant communication. It is possible that there are many signalling mechanisms used and all so possible that different plant species use different mechanisms dependent on the situation and environment. The topic has such a vast array of possibilities that makes it difficult to pinpoint one possible mechanism that works in all situations and with all plant.

In their article Baldwin, Kessler and Halitschke (2002) discussed volatile signalling. In which plants are assumed to release volatiles after herbivores attack and it is thought to be done so in a highly regulated fashion. These VOCs (volatile organic compounds) that are release attract herbivorous predators and so act as indirect defences for the plants.

Plants are highly evolved for gas exchange, and have the capacity to release complex arrangements of VOCs into the air. This ability is what fuels the idea that plants communicate though volatiles. Plants compete for resources, and this gives rise to the idea that plants providing information to competitors are unlikely to be selected for in an environment. This therefore suggests that instead of being dubbed plant 'communication' it should rightly be named 'Eavesdropping elms'. Wounding plants releases volatiles; one reason for this is because the vascular tissue of the plant has been damaged in which VOCs are stored. But it has all so been shown that it is a result of de novo synthesis which is the synthesis of complex molecules from simple molecules such as sugars or amino acids.

Balwin, Kessler and Halitschke's (2002) article goes on to then talk about how the testing for this experiment needs be improved, highly regulated and more similar to the natural environmental conditions that the plants endure in order for it to be seen as a viable mechanism for communication between plants.

I hope to have given a brief overview of how is it possible for plants to communicate, or eves drop via volatiles to increase their environmental fitness.

If you wish to read more on this topic, the reference in given below.

Baldwin, I, Kessler, A, Halitschke, R 2002, 'Volatile signaling in plant–plant–herbivore interactions:
what is real?' Current Opinion in Plant Biology, vol. 5, no.2, pp. 351-354