“Talking” Plants: Airborne Chemical Signals (Part 3)

How a parasitic plant may “sniff out” its victims.

As on the internet, once information is broadcast, even if only among ‘friends’, it becomes available for other unintended and unexpected uses.

Dodder (genus Cuscuta) is a parasitic plant on other plants. But how does this plant find its host?

Apparently, dodder seedlings locate potential hosts by using volatile compounds emitted by plants. These compounds may serve as chemo-attractants.

A dodder seedling can presumably sense these chemicals and adjust its development in order to grow toward its host.

Listen to report on NPR about this subject

View Quicktime movie of dodder in action

More recent news about dodder suggests that this parasitic plant may also tap into chemical signals traveling in the host’s vascular system.

And, interestingly, when tomato plants are parasitized by dodder, the tomatoes apparently use both jasmonic acid and salicylic acid to elicit systemic defense reponses throughout the host plant. (see ref. 2 below)


1. Runyon, J. B., M. C. Mescher, and C. M. De Moraes (2006) “Volatile chemical cues guide host location and host selection by parasitic plants.” Science, Vol. 313, pp.1964-1967. (PDF)

2. Runyon, J. B., M. C. Mescher, G. W. Felton and C. M. De Moraes (2010) “Parasitism by Cuscuta pentagona sequentially induces JA and SA defence pathways in tomato.” Plant, Cell & Environment, Vol. 33, pp. 290-303. (PDF)

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