UNICONAZOLE MITIGATES DISADVANTAGEOUS EFFECTS OF DROUGHT STRESS ON CANNABIS SATIVA L. SEEDLINGS

Uniconazole, S-(+)-uniconazole plays a primary role in plants experiencing different adverse stresses. Its role in hemp (Cannabis sativa L.) drought tolerance is unknown at this time. We assessed the physiological indices of plants under drought stress to elucidate the functions of exogenous uniconazole on the growth of industrial hemp. The results showed that, exogenous uniconazole significantly inhibited plant height, and reduced leaf area. Uniconazole supplementation increased leaf relative water content (RWC) but decreased the proline (Pro) contents. Uniconazole application reduced oxidative damage and accumulations of superoxide anion (O2 center dot-), hydrogen peroxide (H2O2) and malondialdehyde (MDA). Uniconazole increased antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)) activities and promoted the antioxidant defense system to scavenge excessive reactive oxygen species (ROS). The uniconazole-treated plants maintained leaf cell structure integrity and relieved the damage of photosynthetic system subjected to drought stress. Uniconazole enhanced chlorophyll (Chl) content and Pn. Thus, these results indicated that uniconazole had a positive effect in improving the drought tolerance of industrial hemp seedlings.