Plant Research

In laboratory settings, scientists typically place leaves or whole plants in cuvettes to monitor the release of trace gases. Building on this research, the method has been successfully scaled up to large-scale experiments involving grasslands, crops, woodlands or ploughed soil.

Plant damage

There are many causes of plant damage: mechanical injury, weather damage, harvesting and mowing, herbivore attacks, and various stresses (drought, extreme temperatures, high ozone levels, etc.). As the release of VOCs following plant damage is typically a rapid and highly dynamic process, traditional off-line techniques are unsuitable, as they can only analyse a snapshot rather than the entire actual process. Using ProC-TOF-MS, the released VOCs can be analysed directly, offering high sensitivity, high selectivity, and rapid response times and resolution.

When it is necessary to analyse and monitor VOCs released as a result of plant damage, the ProC-TOF-MS offers real-time capability and direct injection without the need for any sample preparation.

Studies have been conducted on the biological VOCs released during leaf wounding and light/dark transitions. The kinetics of substantial emissions of green leaf volatiles (GLVs) and acetaldehyde following wounding and browning have been captured.

Plants attacked by caterpillars release specific VOCs. Volicitin in caterpillar saliva induces defence genes, leading to the formation of indoles and further VOCs, which in turn attract wasps. Wasps utilise the caterpillars in their reproductive cycle, thereby ‘helping’ the plants.

Research could investigate the influence of mycorrhizal fungi on the chemical composition of herbivore-induced plant volatiles (HIPVs) released by leguminous plants attacked by leaf mites, as well as the attractiveness of these HIPVs to natural enemies of the leaf mites.

The plant’s stress response involves the release of a range of VOCs, some of which may serve as warning signals between plants. Interestingly, these VOCs also exhibit markedly different kinetic parameters.

After 30 minutes, plants begin to release indole as an alarm signal, simultaneously triggering defence mechanisms in neighbouring plants. At a later stage, terpenes are also released by the plants as a signal to attract insect predators.

To address this, the ProC-TOF, coupled with an autosampler, enables high-throughput measurement of plant-emitted VOCs.

Conventional analytical methods generally require the use of a concentrator to collect trace amounts of VOCs emitted by plants, followed by a prescribed pre-treatment procedure before injection into a chromatographic-mass spectrometry system.

The collection, pre-treatment and instrumental analysis of a single sample generally take more than 30 minutes, making this approach unsuitable for high-throughput analysis of multiple samples.

The company has independently developed an automated sampling system that enables the ProC-TOF mass spectrometer to rapidly determine trace VOCs online; as the products generally appear in the form of protonated molecular ions, this eliminates the need for pre-treatment steps such as sample collection, enrichment and separation.

These advantages make the ProC-TOF the ideal choice for detecting VOCs emitted by plants under stress. It enables both high-frequency VOC monitoring of individual plants and high-throughput phenotyping studies involving multiple plants, thanks to the instrument’s high sensitivity and efficient data acquisition. 

The automated sampling system then moves to the next plant according to the preset programme for subsequent sampling and analysis.

In less than thirty minutes, this automated sampler can analyse a total of over 100 plants.

The experiment simulated the presence of leaf-feeding Spodoptera litura caterpillars on the plants.

The ProC-TOF-MS offers numerous advantages that are particularly beneficial for agricultural and livestock research, ranging from emissions from farmland to VOCs originating from cattle, pigs, chickens or sheep.