Location of cellulose and callose in pollen tubes and grains of Nicotiana tabacum |
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Authors: | C Ferguson T T Teeri M Siika-aho S M Read A Bacic |
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Institution: | (1) Plant Cell Biology Research Centre, School of Botany, The University of Melbourne, Parkville, Victoria 3052, Australia, AU;(2) European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany, DE;(3) Department of Biochemistry and Biotechnology, Royal Institute of Technology, S-10044 Stockholm, Sweden, SE;(4) VTT Biotechnology and Food Research, Biologinkuja 1, PO Box 1501, FIN-02044 VTT Espoo, Finland, FI;(5) School of Forestry, The University of Melbourne, Creswick, Victoria 3363, Australia, AU |
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Abstract: | The distribution of cellulose and callose in the walls of pollen tubes and grains of Nicotiana tabacum L. was examined by electron microscopy using gold-labelled cellobiohydrolase for cellulose and a (1,3)-β-D-glucan-specific
monoclonal antibody for callose. These probes provided the first direct evidence that cellulose co-locates with callose in
the inner, electron-lucent layer of the pollen-tube wall, while both polymers are absent from the outer, fibrillar layer.
Neither cellulose nor callose are present in the wall at the pollen-tube tip or in cytoplasmic vesicles. Cellulose is first
detected approximately 5–15 μm behind the growing tube tip, just before a visible inner wall layer commences, whereas callose
is first observed in the inner wall layer approximately 30 μm behind the tip. Callose was present throughout transverse plugs,
whereas cellulose was most abundant towards the outer regions of these plugs. This same distribution of cellulose and callose
was also observed in pollen-tube walls of N. alata Link et Otto, Brassica campestris L. and Lilium longiflorum Thunb. In pollen grains of N. tabacum, cellulose is present in the intine layer of the wall throughout germination, but no callose is present. Callose appears
in grains by 4 h after germination, increasing in amount over at least the first 18 h, and is located at the interface between
the intine and the plasma membrane. This differential distribution of cellulose and callose in both pollen tubes and grains
has implications for the nature of the β-glucan biosynthetic machinery.
Received: 20 February 1988 / Accepted: 25 March 1998 |
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Keywords: | : Callose Cellobiohydrolase Cellulose Nicotiana (pollen tube) Pollen grain Pollen tube |
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