Root-secreted VOCs

Steeghs et at. have described the use of PTR-MS, in conjunction with GC-MS, to explore VOCs in the rhizosphere and their generation resulting from biotic stresses [230]. This area of research is important because plant roots are believed to release between 5% and 20% of all photosynthetically fixed carbon and therefore these roots create and maintain a carbon-rich environment for rhizosphere organisms, such as plant pathogens and symbiotic microbes from which VOCs can also be emitted. The research team focused on root-secreted VOCs from Arabidopsis. Simple volatile metabolites were mainly observed, such as ethanol, acetaldehyde, acetic acid, ethyl acetate, 2-butanone, 2,3,-butanedione and acetone, together with the monoterpene 1,8-cineole. Some VOCs were produced regardless of how the plants were treated (e.g. with compatible or incompatible bacteria), whereas other VOCs were induced specifically as a resull of differenf compatible and incompatible interactions between microbes and insects and Arabidopsis roots. 

This is defined to be the region of soii that surrounds a piant root and is directiy influenced by root secretions and soii microorganisms. 

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Steeghs, M.M.L., Pal Bais, H., de Gouw, X, Goldan, P, Kuster, W., Northway, M., Fall, R., Vivanco, XM. (2004) Proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted VOCs inArabidopsis. Plant Physiology, 135,47-58. 

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