Cold acclimation can induce microtubular cold stability in a manner distinct from abscisic acid

The response of cortical microtubules to low temperature was investigated for the Chinese winter wheat (Triticum aestivum L.) cultivar Jing Nong 934. Microtubules in the cortex of the root elongation zone disassembled rapidly in response to a cold shock of -7 degrees C and reassembled upon rewarming to 25 degrees C. The microtubules acquired resistance against this cold shock in response to cold acclimation in chilling, but non-freezing, temperature or after a treatment with abscisic acid (ABA). Cold acclimation and ABA differed with respect to the appearance of microtubules: fine, transverse strands were observed after cold acclimation, whereas ABA produced steeply oblique microtubule bundles. The findings are discussed in terms of an ABA-independent pathway for acquired cold stability of microtubules.