Monitoring of lipoxygenase-related plant emission for early detection of drought stress in greenhouse

Early detection of plant stress is a key to effective plant management for crop production. Drought stress is a common abiotic stress in crop production and early detection of drought stress allows us to improve water usage effi ciency and crop quality by demandbased irrigation. This study demonstrated an early detection of drought stress by monitoring lipoxygenase-related plant emission from tomato plants in greenhouse. The drought stress was induced by stopping irrigation, and then re-irrigated. To quantify the effect of the drought stress on plant, leaf water potential and leaf photosynthetic rate were measured. During air sampling for plant emission monitoring, plants were temporarily enclosed in a plastic bag and then the concentrated volatiles inside the bag were captured by purge and trap technique. The air samples were analyzed with gas chromatography-mass spectrometry. During the drought stress treatment, leaf water potential and photosynthetic rate decreased. Furthermore, slight wilting of leaves was observed at the end of the treatment. After the re-irrigation, leaf water potential and photosynthetic rate increased and the wilting symptoms disappeared. The recoverable drought stress induced lipoxygenase-related plant emission of (Z)-3-hexenal, n-hexanal and (Z)-3-hexenol and the emission stopped after the recovery. This result suggests that early detection of drought stress by monitoring lipoxygenase-related plant emission is feasible under greenhouse conditions