Seed treatment with the antioxidant Ambiol enhances membrane protection in seedlings exposed to drought and low temperatures

Because of the harsh environments in boreal clearcuts, it is necessary to plant only stress-tolerant seedlings. To test the use of antioxidants to enhance stress tolerance, Ambiol (2-methyI-4-dimethylamino-methyl-5-hydrohybenzimidazole dihydrochloride) was applied to jack pine (Pinus banksiana Lamb.) and black spruce [Picea mariana (Mill.) BSP], using a 24-h seed soak. For seedlings treated with Ambiol (0, 0.1, and 10 mg 1(-1)), membrane leakage and visible damage were compared following the application of drought (by withholding water), and frost (-10 degreesC for 1.5 h). Although black spruce was more responsive to treatment than jack pine, the effectiveness of Ambiol varied depending on the type of stress, species and the concentration. Ambiol reduced membrane leakage under both drought and frost. The lower (0.1 mg 1(-1)) concentration of Ambiol reduced membrane leakage in black spruce needles under severe drought, while a higher concentration (10 mg 1(-1)) provided more protection when jack pine was exposed to low temperatures. The antioxidant Ambiol enhanced membrane protection and reduced visible damage symptoms in seedlings following the application of stress. The seed-soak method provided a simple, cost-effective, method of conditioning seedlings.