Extraction of allelochemicals from germinated wheat seeds and their inhibitory effects on cucumber

AbstractMicrowave‐assisted extraction (MAE) of allelochemicals from germinated wheat (Triticum aestivum L.) seeds was optimized by using response surface methodology. Under the optimal conditions (temperature 70 °C, power 283 W, liquid/solid ratio 17 L kg–1 and time 20.0 min), the inhibitory rate of allelochemicals on cucumber (Cucumis sativus L.) seeds germination was 64.21±1.99%. Three main allelochemicals including p‐Hydroxybenzoic acid, 3‐methoxy‐4‐hydroxycinnamic acid, and 3,5‐dimethoxy‐4‐hydroxybenzoic acid were identified by liquid chromatography–tandem mass spectrometry (LC‐MS/MS) analysis. These allelochemicals significantly inhibited the growth of cucumber seeding and root. Furthermore, malondialdehyde (MDA) content increased and root vitality and amylase activity decreased after the treatment of allelochemicals. Glutathione (GSH) content, glutathione peroxidase (GSH‐Px), and glutathione transferase activities rose first and then fell with the allelochemicals concentration increased. These results suggested that the extract from germinated wheat seeds could inhibit the growth of cucumber by affecting the physiological and biochemical processes in cucumber.