Abstract
Individual microtubules dynamically alternate between two states, growth by polymerization and shrinkage by depolymerization, the property termed "dynamic instability." In plant interphase cells microtubules organize into cortical arrays that oriented perpendicular to the direction of cell elongation in rapidly elongating cells. To study how microtubule dynamic instability affects cortical microtubule orientations during cell elongation ( and thereby the direction of cell elongation ), the transgenic Arabidopsis plants in which β-tubulin fused with GFP were expressed to visualize individual microtubules were analized in vivo by confocal laser scanning microscopy and microtubule dynamic instability parameters were quantified. Next the dynamic instability parameters were compared between plants grown on agar media containing the microtubule-interacting drugs and control plants. At the drug concentrations used, seedling roots showed left-handed helical growth. We also plan to analyze the dynamics parameters of helical growth mutants.
