Effects of Exogenous Cannabidiol on Tobacco Seed Germination under Cd and Cr Stress

PurposeTo explore the effect of exogenous cannabidiol (CBD) on tobacco seed germination and seedling growth under heavy metal stress.

MethodsK326 and burley tobacco Eyan No.1 seeds were used to study the effects of different mass concentrations of CBD (0, 1, 5, 25 mg/L) on the indexes of tobacco seed germination and seedling growth under Cr (8 mg/L) and Cd (30 mg/L) stress.

ResultsThe addition of CBD could slightly inhibit the germination of K326 seeds, reduced the germination rate by 2.78% at most, but improve the quality of seedlings in the absence of heavy metals. The germination rate and vigor index of Eyan No.1 seeds added with 25 mg/L CBD were significantly increased by 5.79% and 47.32%, respectively. Under heavy metal stress, 5 and 25 mg/L CBD had the best alleviation on the seed germination of K326 and Eyan No.1 under Cr stress. The seed vigor index of K326 and Eyan No.1 was significantly increased by 49.18% and 30.87% compared with Cr treatment alone, and the mortality was reduced by 67.73% and 76.04%, respectively. 5 mg/L CBD had the best alleviation on Cd stress. The germination index and dry weight of tobacco seeds were increased by 8.11% and 79.24% (K326), 25.81% and 82.15% (Eyan No.1), respectively compared with Cd treatment alone.

ConclusionCBD could effectively alleviate the toxic effects of Cr and Cd on tobacco seed germination, and promote seedling growth. However, the appropriate mass concentration of CBD should be selected according to the type of heavy metals, stress degree and plant varieties.