STABILIZING MICROTUBULES WITH TAXOL INCREASES MICROFILAMENT STABILITYDURING FREEZING OF RYE ROOT-TIPS

We have used double fluorescence labelling to investigate the effect o f freezing on microtubules and microfilaments in root-tip cells of rye (Secale cereale L. cv Rymin). Freezing to -5-degrees-C (which does no t kill these cells) caused partial depolymerization of both, but micro filaments were more resistant than microtubules. When microtubules wer e stabilized against freeze-induced depolymerization by pretreating se edlings with taxol, microfilaments exhibited enhanced stability as wel l. Almost all the frozen cells containing taxol-stabilized microtubule s also contained microfilaments. When seedlings were treated with the microtubule-destabilizing drug APM prior to freezing, microfilaments b ecame more susceptible to freeze-induced depolymerization than in cont rols. These data suggest a physical interaction between microtubules a nd microfilaments in these cells.