Chilling stability of microtubules in root-tip cells of cucumber.

The chilling stability of microtubules was investigated in root-tip cells of cucumber (Cucumis sativus L.) using immunofluorescence labeling and a confocal laser scanning microscope. After low temperature (4 degrees C) treatment for 5 h, we found not only chilling-stable cortical microtubules under the plasma membrane of the root-tip cells, but also chilling-stable punctate microtubules in the cytoplasm, which might be the microtubules associated with organelles. 6-Dimethylaminopurine (6-DMAP), an inhibitor of protein kinase, reduced the chilling stability of the cortical microtubules in the cells. When the root-tip cells were restored to normal growth temperature (28 degrees C), the recovery of the microtubules seemed to be closely associated with the microtubules still remaining in these cells after chilling treatment.