The Distribution and Morphology Alterations of Microfilaments and Microtubules in Mesophyll Cells and Root-Tip Cells of Wheat Seedlings under Enhanced Ultraviolet-B Radiation

摘要

The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-1), were examined through the confocal laser scanning microscope (Model FV1000, Olympus, Japan). Microtubule was labeled with an indirect immunofluorescence staining method, and microfilament was labeled with fluorescein isothiocyanate-phalloidin (FITC-Ph) as probes. The results indicated that microtubules in mesophyll cells, compared with the controls, would be depolymerized significantly, and dispersed randomly showing some spots or short rods in the cytoplasm, under the enhanced UV-B radiation condition. The microtubule bundles tended to be diffused, and the fluorescence intensity of that significantly decreased. The distribution pattern of microfilaments, which usually arranged parallelly in control cells, was broken up by enhanced UV-B radiation. We further investigated the distribution and morphology of microtubules in root-tip cells during every stage of cell division, and found that these aberrant phenomena of microtubules were often associated with abnormal cell division. Our findings suggested that the distribution, morphology and structure of cytoskeleton in mesophyll cells and root-tip cells of wheat seedlings would be affected by enhanced UV-B radiation, which might be related to abnormal cell division caused by enhanced UV-B radiation as an extracellular signal.