Abstract
The dynamics of the microtubule (MT) were studied by α-tubulin immunofluorescence methods during the polleng rain ontogeny inTradescantia paludosa. Before the microspore division, interphase nuclei of themicrospore cells were twice displaced from the center to one side (NM-1) and from the side to the center near the inner wall (NM-2). During NM-1, a few MTs appeared around the nucleus, but the movement was not interrupted by colchicine treatment. In NM-2, however, which was essential to the unequal division of microspores, many MTs and MT bundles became organized and shifted in a manner corresponding to the nuclear movement. This movement was inhibited by the colchicine treatment. It was concluded that NM-2 was dependent on the MT cytoskeleton, but NM-1 was independent.
Througthout the microspore division, mitotic spindles were organized asymmetrically. From prophase to prometaphase, the spindle began to construct itself in the vegetative pole preceding the generative pole. The half-spindles were asymmetric at the metaphase and the phragmoplast developed curving toward the generative pole at the telophase. No pre-prophase band of MTs was observed throughout the cell cycle.
The relationship between the characteristic MT dynamics and the nuclear movement, or unequal cell division, was revealed and is discussed here.
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Bassel, A.R., C.C. Kuehnert andJ.H. Miller. 1981. Nuclear migration and asymmetric cell division inOnoclea sensibilis spores: An ultrastructural and cytochemical study. Amer. J. Bot.68: 350–360.
Burgess, J. 1970a. Microtubules and cell division in the microspore ofDactylorchis fuschii. Protoplasma69: 253–264.
— 1970b. Cell shape and mitotic spindle formation in the generative cell ofEndymion non-sriptus. Planta95: 72–85.
Doonan, J.H. 1986. Microtubules connect the migrating nucleus to the prospective division site during side branch formation in the moss,Phycomitrella patens. Eur. J. Cell Biol.41: 157–164.
Hagerup, O. 1938. A peculiar asymmetrical mitosis in the microspore ofOrchis. Hereditas24: 94–96.
Heslop-Harrison, J.D. andD.H. Northcote. 1966a. Organization of microtubules and endoplasmic reticulum during mitosis and cytokinesis in wheat meristems. J. Cell Sci.1: 109–120.
— and —. 1966b. Cell division in the formation of the stomatal complex of the young leaves of wheat. J. Cell Sci.1: 121–128.
Heslop-Harrison, J. 1968. Synchronous pollen mitosis and the formation of the generative cell in massulate orchids. J. Cell Sci.3: 457–466.
Kakimoto, T. andH. Shibaoka. 1987. Actin filaments and microtubules in the preprophase band and phragmoplast of tobacco cells. Protoplasma140: 151–156.
Katsuta, J. andH. Shibaoka. 1988. Role of the cytoskeleton and the cell wall in nuclear positioning in tobacco BY-2 cells. Plant Cell Physiol.29: 403–413.
Lloyd, C.W. andJ.A. Traas. 1988. The role of F-actin in determining the division plance of carrot suspension cells. Drug studies. Development102: 211–221.
Sax, K. 1935. The effect of temperature on nuclear differentiation in microspore development. J. Arnold Arboretum16: 301–310.
Sheldon, J.M. andH.G. Dickinson. 1986. Pollen wall formation inLilium: The effect of chaotropic agents, and the organization of the microtubular cytoskeleton during pattern development. Planta168: 11–23.
Tanaka, I. andM. Ito. 1981. Control of division patterns in explanted microspores ofTulipa gesneriana. Protoplasma108: 329–340.
Tanaka, I., C. Kitazume andM. Ito. 1987. The isolation and culture of lily pollen protoplasts. Plant Sci.50: 205–211.
Terasaka, O. 1982. Nuclear differentiation of male gametophytes in gymnosperms. Cytologia47: 27–46.
Terasaka, O. andT. Niitsu. 1987. Unequal cell division and chromatin differentiation in pollen grain cells. I. Centrifugal, cold and caffeine treatments. Bot. Mag. Tokyo100: 205–216.
— and —. 1989. Pecliar spindle configuration in the pollen tube revealed by anti-tubulin immunofluorescence method. Bot. Mag. Tokyo102: 143–147.
Terasaka, O. andR. Tanaka. 1974. Cytological studies on the nuclear differentiation in microspore division of some angiosperms. Bot. Mag. Tokyo87: 209–217.
Van Lammeren, A.A.M., C.J. Keijzer, M.T.M. Willemse andH. Kieft. 1985. Structure and function of the microtubular cytoskeleton during pollen development inGasteria verrucosa (Mill.) H. Duval. Planta165: 1–11.
Vogelmann, Th. C., A.R. Bassel andJ.H. Miller. 1981. Effects of microtubule-inhibitors on nuclear migration and rhizoid differentiation in germinating fern spores (Onoclea sensibilis). Protoplasma109: 295–316.
Wick, S.M., R.W. Seagull, M. Osborn, K. Weber andB.E.S. Gunning. 1981. Immunofluorescence microscopy of organized microtubule arrays in structurally stabilized meristematic plant cells. J. Cell Biol.89: 685–690.
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Terasaka, O., Niitsu, T. Unequal cell division and chromatin diffrentiation in pollen grain cells. Bot Mag Tokyo 103, 133–142 (1990). https://doi.org/10.1007/BF02489621
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DOI: https://doi.org/10.1007/BF02489621