Abstract:

Our objective was to study the possible function of expansin AtEXP1 in the stomatal movement of transgenic tobaccos with over-expressed AtEXP1, the differences of stomatal movement under the condition of different stimuli between the transgenic and wild plants were analyzed. Bioassays on epidermal peels showed that the stomatal opening induced by light, K⁺ and the stomatal closure induced by Ca²⁺, ABA and darkness were promoted by over-expressed AtEXP1, but the density of stomata had little difference between the transgenic and wild plants. Moreover, the transgenic plant had significantly higher photosynthesis and transpiration rates than the wild plant under favorable conditions. All the results suggested that via altering the characteristic of the guard cell wall, over-expressed AtEXP1 increased the sensitivity of stomata to different stimuli, then involved in the regulation of tobacco stomatal movement, showing that expansin AtEXP1 did play an active role in the regulation of stomatal movement.

Key words: Expansin, AtEXP1, Transgenic tobacco, Stomatal movement