Innovative Bvoc Technologies to Directly Fine Tune Crop Stress While Building System Resilience.

Plant based sensor systems, because they monitor the plant itself, have the potential to solve many of the issues associated with sensors that infer plant water status from environmental characteristics. Direct measurement of stress level in the crop would allow for more accurate assessments of water requirements and reduce the lag time between crop and sensor response. In this work we identified Biogenic Volatile Organic Compounds (BVOCs) that correlate with quantifiable measures of plant water deficit stress of various levels. These compounds represent a sub-set group of secondary metabolites that are not emitted from anthropogenic systems, but from the crop as it experiences stress. Experiments were conducted involving well-watered peanut (Arachis hypogaea L.) plants (control) vs. reduced water (drought) conditions. BVOC emissions were characterized at various time points during the day: dusk, pre-dawn, and midday; as well as dates that differed in soil water conditions. Midday BVOC collections were coupled with measures of gas exchange to correlate BVOC signatures with transpiration and photosynthesis. Overall BVOC signature differed among water treatments and time of day. Two particular BVOCs were identified as most sensitive to soil water conditions: cis-Hexen-1-ol and cyclohexene. The effect of time of day was seen as greatly reduced levels of BVOCs at the pre-dawn collection time point in comparison to the signatures at the mid-morning collection. Important information for refinement of collection techniques was also elucidated – the plastic, aluminized bags utilized in the field collection in 2016 were effective at providing a very easy, inexpensive method of collection, while pre-treating in the oven could virtually eliminate the background VOCs emitted from the plastic, allowing for more accurate collections. This work indicates the promise of utilizing BVOCs for direct sensing of plant stress, possibly leading to site-specific management of irrigation for reducing crop drought impacts.