Abstract:Polyethylene glycol (PEG) induced osmotic stress increased the contents of putrescine (Put), spermidine (Spd) and spermine (Spm) in seedlings of drought-resistant wheat strains Zhou and the content of Put in seedlings of drought-sensitive wheat Wen 6. Exogenous Spd (1 mmol/L) obviously increased the content of Spd in seedlings of Wen 6 and its resistance to water stress increased to some extent. Methylglyoxyl-bis (guanylhydrazone) (MGBG,1 mmol/L), an inhibitor of biosynthesis of Spd and Spm, increased the increased the content ofPut in wheat seedlings of Zhou 12 under water stress，but decreased the contents ofSpd and Spm as well as its drought resistance.