Effects of opening vessel lid on stomatal traits of tissue-cultured plantlets of rhubarb during acclimatization.

Tissue-cultured plantlets were exposured to the air to study the effects of opening vellel lid on the stomatal traits of rhubarb during acclimatization.During the 0-14 days acclimatization,the stomatal size,it's length and width decrease,then tend to stabilize with the time prolonged.Stomatal closure rate substantially increases,reaching 76.5%.After 14 days' expe-rience,leaf epidermis cells density increased significantly,stomatal density and stomatal index slightly increase.Vessel lid closing 7d and vessel lid opening 7d could recover the stomatal function rapidly as soon as possible.Microscopic observation demonstrated that there are great diffe-rences in stomatal structure among leaves from the plantlets with different opening-time treatments,while there are no significant difference for exercising plantlets under light condition or under dark.