This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (17) Citing Articles via Google Scholar Google Scholar Articles by Bartolo, M. E. Articles by Carter, J. V. Search for Related Content PubMed PubMed Citation Articles by Bartolo, M. E. Articles by Carter, J. V. Agricola Articles by Bartolo, M. E. Articles by Carter, J. V.

Environmental and Stress Physiology

Effect of Microtubule Stabilization on the Freezing Tolerance of Mesophyll Cells of Spinach ¹

Department of Horticultural Science, University of Minnesota, St. Paul, Minnesota 55108, Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108

Freezing, dehydration, and supercooling cause microtubules in mesophyll cells of spinach (Spinacia oleracea L. cv Bloomsdale) to depolymerize (ME Bartolo, JV Carter, Plant Physiol [1991] 97: 175-181). The objective of this study was to determine whether the LT₅₀ (lethal temperature: the freezing temperature at which 50% of the tissue is killed) of spinach leaf tissue can be changed by diminishing the extent of microtubule depolymerization in response to freezing. Also examined was how tolerance to the components of extracellular freezing, low temperature and dehydration, is affected by microtubule stabilization. Leaf sections of nonacclimated and cold-acclimated spinach were treated with 20 micromolar taxol, a microtubule-stabilizing compound, prior to freezing, supercooling, or dehydration. Taxol stabilized microtubules against depolymerization in cells subjected to these stresses. When pretreated with taxol both nonacclimated and cold-acclimated cells exhibited increased injury during freezing and dehydration. In contrast, supercooling did not injure cells with taxol-stabilized microtubules. Electrolyte leakage, visual appearance of the cells, or a microtubule repolymerization assay were used to assess injury. As leaves were cold-acclimated beyond the normal period of 2 weeks taxol had less of an effect on cell survival during freezing. In leaves acclimated for up to 2 weeks, stabilizing microtubules with taxol resulted in death at a higher freezing temperature. At certain stages of cold acclimation, it appears that if microtubule depolymerization does not occur during a freeze-thaw cycle the plant cell will be killed at a higher temperature than if microtubule depolymerization proceeds normally. An alternative explanation of these results is that taxol may generate abnormal microtubules, and connections between microtubules and the plasma membrane, such that normal cellular responses to freeze-induced dehydration and subsequent rehydration are blocked, with resultant enhanced freezing injury.

¹ Supported by the U.S. Department of Agriculture grant 85-CRCR-1-1666. This paper is a contribution from the Minnesota Agricultural Experiment Station, Journal Article No. 18754.

This article has been cited by other articles:

				A. Abdrakhamanova, Q. Y. Wang, L. Khokhlova, and P. Nick Is Microtubule Disassembly a Trigger for Cold Acclimation? Plant Cell Physiol., July 15, 2003; 44(7): 676 - 686. [Abstract] [Full Text] [PDF]

				Q. Y. Wang and P. Nick Cold Acclimation Can Induce Microtubular Cold Stability in a Manner Distinct from Abscisic Acid Plant Cell Physiol., September 1, 2001; 42(9): 999 - 1005. [Abstract] [Full Text] [PDF]

				R. D. de Castro, A. A.M. van Lammeren, S. P.C. Groot, R. J. Bino, and H. W.M. Hilhorst Cell Division and Subsequent Radicle Protrusion in Tomato Seeds Are Inhibited by Osmotic Stress But DNA Synthesis and Formation of Microtubular Cytoskeleton Are Not Plant Physiology, February 1, 2000; 122(2): 327 - 336. [Abstract] [Full Text]