Among the most prominent benefits of PTR-MS are real-time capability and direct injection without any sample preparation. These are of utmost importance when VOCs released upon plant damage have to be analyzed and monitored. In a lab environment scientists usually put leaves or whole plants in cuvettes in order to monitor released trace gases. However, also many large scale experiments involving grassland, crops, woodland or ploughed soil have been performed with great success.
Plant damage can occur due to many reasons: mechanical wounding, weather damage, harvesting and mowing, herbivore attacks, and also various types of stress (drought, extreme temperatures, high ozone levels, etc.). As the VOC release upon plant damage typically is a rapid and highly dynamic process, conventional off-line technologies are not suitable because they are only capable of analyzing snapshots, but not the actual process as a whole. With PTR-MS the released VOCs can be directly analyzed, with high sensitivity, selectivity and at time resolutions of up to 10 Hz.
One early example of a typical plant study was published in 2011 by Brilli et al. where biogenic VOCs released upon leaf wounding and light / dark changing were investigated in detail. The authors state that "PTR-TOF measurements unambiguously captured the kinetic of the large emissions of green leaf volatiles (GLVs) and acetaldehyde after wounding and darkening" and they even discovered a new class of C5 compounds in wounding induced biogenic VOC emission.
T. Turlings and M. Held (Université de Neuchâtel) showed that plants under attack from caterpillars release specific VOCs. Volicitin in the saliva of caterpillars induces defense genes leading to the formation of indole and further VOCs which attract wasps. The wasps use the caterpillars in their reproduction cycle and by that "do a favor" to the plants.
Utilizing an IONICON PTR-TOFMS instrument Schausperger et al. investigated the effects of an mycorrhizal fungus on the chemical composition of herbivore-induced plant volatiles (HIPVs) emitted by bean plants attacked by spider mites and attraction of the spider mites’ natural enemy to these HIPVs. "Our study provides a key example of an adaptive indirect HIPV‐mediated interaction of a below‐ground micro‐organism with an above‐ground carnivore."
These are just some examples from the hundreds of high-class plant studies which have been made possible with the unique IONICON PTR-MS technology. We are happy to provide you with a personal showcase tailored to your specific plant study application! This will also answer the question which IONICON PTR-MS instrument combined with which add-ons will make the perfect pairing for your specific needs.