Abstract: A method for measuring leaf area was developed using digital camera and Photoshop software.The measured data from digital camera was compared with the values from paper-cut and instrumental scanning methods and etc.The results showed that there was highly significant correlation between the results of digital image processing method and other traditional methods.The resolution,pixel number of leaf picture and camera angle had no significant influence on the results of the method.Relative low variation,accuracy,no-destructive and low price are the main advantages of the method,which is applicable and reliable in plant physiological ecology research.

Key words: Poplar, Water stress, Nitric oxide, Oxidation damage, Protection