Abstract:Roles of microtubules (MT) in regutlating stomatal movements of Vicia faba L. were investigated. The results indicated that apertures of open or closed stomata were not significantly influenced by pretreatment with amiprophos-methyl (APM) 50 mg/L, a specific inhibitor of plant MT polymerization, for 60 min. However, the induction of stomatal movements was inhibited by pretreatment with APM. The inhibition was reversible after APM was removed for 4 h. The induction of stomatal closure by ABA, Ca2 + , or darlmess was inhibited by pretreatment with APM 50 mg/L for 60 min in the light, suggesting that MT might play roles in stomatal closure. The stimulation of stomatal opening by fight was inhibited by pretreatment with APM in the dark, suggesting that MT might regulate stomatal opening as wen.