Abstract: Drip-irrigation pot experiment was used to study the response relationship between ABA content and stomatal conductance of cotton plant at bud stage under nitrogen application and drip irrigation. The results showed that,at the bud stage,there was a positive correlation between ABA content and stomatal conductance of potted cotton plant under drip irrigation and different N treatments,i.e. the 2 g ,4 g and 6 g·pot^-1; the correlation coefficients (r) were 0.905,0.942 and 0.958,and the T-test significance levels were 0.034,0.016 and 0.010,respectively. The models with 2 g·pot^-1,4 g·pot^-1 and 6 g·pot^-1 were quadratic,exponential and exponential functions respectively,and the determination coefficients (R²) in model fitting were 0.975,0.894 and 0.946 respectively. The F-test significance levels were 0.025,0.015 and 0.005 respectively,reaching the significant level and extremely significant level. Therefore,the regression model studied in this paper was used to well describe the correlation between the ABA cotton and the stomatal conductance of cotton plant under drip irrigation and also the model characteristics at different N-fertilization levels.

Key words: drip irrigation, nitrogen, cotton plant, stomatal conductance, ABA, bud stage