I have talked in previous blogs about how plants use chemical
signals or VOCs volatile organic compounds in order to communicate messages to
each other through the air. But one of the newer and less researched forms or
plant communication are those types in which happen under the ground. Within
the rhizosphere which is the densely populated area in the soil in which plant
root systems must compete with other organisms for access to nutrients (Bais et al 2004).
So how exactly do plants communicate through this densely
populated network? We know that mycorrhizal fungi have an impact on plant
communication but other research suggest that root exudates also play are large
role in the function of plant communication. Root exudates are the chemicals
secreted by root systems into the soil and they are known to perform a
multitude of functions. One reason why plants release these exudates is as a
defence mechanism against pathogens. Most root secreted compounds belong to the
chemical class of phenolics, and it is the terpenoids that have antibacterial
and antifungal properties. It has been founds that not only do plant roots release
exudates into the rhizosphere but they also they release VOCs when defending
themselves against predators, it was previously thought that VOCs where only
released above ground by plants (Baetz 2014)
This is just another example of how plants communicate. By
releasing these chemicals into the soil from their roots systems they are able
to ward off any pathogens and defend themselves. Some exudate chemicals even
provide benefit by luring certain microbes to them that they may get an
advantage from such as mycorrizae.
References
Baetz U. & Martinoia E. (2014) Root exudates: the hidden
part of plant defence, Trends in Plant
Science 2. 90-98.
Bais P.H., Park S. W., Weir L. T., Callaway M. R and Vivanco
M. J. (2004) How plants communicate using the underground information
superhighway. Trends in Plant Science 1. 26-32
I find the various chemicals produced and/or secreted by plants to be very interesting. Do you know if any of these pathogen-fighting exudates are being investigated for medical uses?
ReplyDeletePlants have been used in medicine for 100s of year. I don't know the exact exudates components that are used in medicine. They definitely use them for there sterilizing features in medicine on injuries. Of all the plants species used in medicine 48 of them are used for there excretions and exudates.
ReplyDeleteThis link will take you to a book that describes alot of plants and there uses in medicine.
http://www.tandfonline.com/doi/abs/10.1300/J044v04n01_07#.U4QH5ChWmik
That’s interesting. What types of exudates can be released? Does release of specific exudates result in all plants showing the same response? Over what scale would we be expecting exudates to function?
ReplyDeleteExudates of all different types are released to perform different functions for plants. The chemical compositions of exudates for different plants species could different but these secretion are generally made up of amino acids, organic acids, sugars, phenolics and sometimes proteins and polysaccharides. All plants have two types of exudates that they release, the first types of exudates are waste materials from the plants and the effects of these are unknown. The second type of exudates are compounds that have known functions such as lubrication or defense.
ReplyDeletehttp://www.annualreviews.org/doi/full/10.1146/annurev.arplant.57.032905.105159