It was investigated that the effects of guaiacol on the growth index of radish seedlings( root length, shoot length, dry weight) from different action methods, guaiacol dissolved in water, attached to filter paper and the form of steam respectively. The results showed that guaiacol dissolved in water, attached to filter paper and the form of steam could all influence the growth of radish seedlings. The effects of guaiacol dissolved in water on radish depend on the concentration, guaiacol of higher concentra...