Abstract: The effects of different agents on seed germination and growth characteristics of tobacco varieties with different drought tolerance were studied in this paper Seeds of two tobacco varieties with different drought tolerance were primed in different concentration solutions of paclobutrazol， calcium chloride， proline and salicylic acid Then， the germination， seedling growth and physiological changes under drought stress (simulating with 15% polyethylene glycol 6000) were measured The results showed that the germination and seedling growth were inhibited， however， the activities of ascorbate peroxidase (APX)， catalase (CAT)， peroxidase (POD) and superoxide dismutase (SOD) in tobacco seedlings were enhanced and the malondialdehyde (MDA) concentration were decreased after treated with paclobutrazol (PP333) The germination parameters， root length， seedling length， seedling fresh and dry weight were improved， the activities of APX， CAT， POD and SOD were enhanced and the MDA concentration were decreased in two tobacco varieties after treated with calcium chloride， proline and salicylic acid The treatment of 80 mg·L-1 salicylic acid had the best effects among all treatments， suggesting that this treatment can be used to improve drought tolerance of tobacco seeds and seedlings.

Key words: tobacco, seed germination, drought tolerance, seed priming