Abstract: Some researchers suggested that the microtubule has an important effect on stomatal movement. The K⁺ channel activity of cytoplasmic membrane of guard cell was dependent on polymerization and depolymerization mobile changed of microtubule. Microtubule system may control stomatal movement induced by regulating the K⁺ channel of guard cell. Microtubule dispolymeric leads to the K⁺ channel closed. Guard cell could not absorb water so that it will inhibit stomata open. Some scholars regarded that Camptothecin(CPT) and its analogue could associate with microtubule, reduce the structure stability of microtubule. The mechanism maybe inhibit high molecule weight microtubule associated protein to associate with microtubule. But we were short of the deep proofs of studying the ecological biochemistry function of CPT; we were spraying 0.011 5 mmol·L^-1 CPT solution on leaves and used 10% PEG₈₀₀₀ solution to stimulate drought stress. The research results indicated that sprayed 0.011 5 mmol·L^-1 CPT solution and 10% PEG₈₀₀₀ could induce Camptotheca acuminata and Nicotiana tabacum seedlings stomatal to close. We suggested that CPT could associate with microtubule, induce stomatal movement.

Key words: Camptothecin, Camptotheca acuminata, Nicotiana tabacum, stomatal movement