EFFECT OF COLCHICINE ON STOMATAL MOVEMENTS AND ON GUARD-CELLS ULTRASTRUCTURE OF TRADESCANTIA-VIRGINIANA

In stomata of Tradescantia virginiana L., microtubules were observed in guard cells during stomatal opening, but never in open or closed stomata. These microtubules were present along the plasmalemma and in the parietal cytoplasm on the paradermal section. They were located near the wall foldings. Colchicine 1 mM and 10 mM inhibited the movement during stomatal opening. This drug inhibits the addition of tubulin molecules to microtubules, leading to microtubule depolymerization. Ultrastructural variations of guard cells produced by colchicine were examined. These results suggest that microtubules might be involved in the stomatal opening.