Distribution of microtubules during the growth of tobacco pollen tubes

Abstract

The distribution of microtubules was investigated in Nicotiana tabacum pollen tubes at different stages of tube growth by immunofluorescence microscopy. Using specific antibodies, the presence of microtubules consisting of different tubulin isoforms was tested, a-,/3-and tyrosinated ~t-tubulin were present within the tube, whereas the acetylated form was lacking. The presence of tubulin subunits in pollen tube extracts was al~o investigated by immunobiotting analyses. The use of a confocal laser scanning microscope integrated with computer-assisted imaging, allowed a detailed visualization of the microtubule distribution and organization. Cytoplasmic microtubules organized as short bundles with various orientations were detected at the apex of long tubes. Nicotiana tabacum I pollen tube growth / microtubules / tyrosinated ~-tubulin / acetylated ct-tubulin / confocal laser scanning microscope

Dynein heavy chain-related polypeptides are associated with organelles in pollen tubes of Nicotiana tabacum

“…Interestingly, particle distribution is reminiscent of the microtubule pattern during tube elongation, since most particles observed were concentrated in the area behind the apex, within relatively short tubes and extending to the tip in pollen tubes longer than 200 µm (see Del . Previous immunofluorescence experiments showed microtubules in pollen tubes distributed mainly in the cortical region of the cytoplasm, although they were also seen in the central region of the pollen tubes (Pierson and Cresti 1992;Del Casino et al 1993). A partial overlapping can be hypothesized in this case between microtubules and dynein-related polypeptides since in cross sections of Dy-l-stained tubes there was no difference in the distribution of spots between cortical and cytoplasmic zones.…”

The cytoskeleton in plant and fungal cell tip growth

“…Clear helical configuration of the MT arrays can be distinguished along the tubes (Fig. 10c; pollen tubes, Pierson et al ., 1986, 1989; Lancelle et al ., 1987; Tiezzi et al ., 1987; Tiwari & Polito, 1988a; Del Casino et al ., 1993: reviews by Steer & Steer, 1989; Pierson & Cresti, 1992; Mascarenhas, 1993; Cai et al ., 1997: root hairs, Lloyd, 1983; Lloyd & Wells, 1985; van Amstel & Derksen, 1985). In pollen tubes of Lilium longiflorum the axially orientated MTs were observed to be interlinked by bridge or zigzag‐like structures, indicating that they might have a scaffold function (Pierson & Cresti, 1992 and references therein).…”

“…A quantitative analysis on transmission electron microscope level performed on hyphae of Saprolegnia ferax corroborated these results (Heath & Kaminskyj, 1989). Interestingly, the abundance of MTs has been observed to vary within one species according to the growth medium (Roos & Turian, 1977) and the developmental stage (Del Casino et al ., 1993).…”

Regulation of pollen tube growth

“…In these preparations MT easily break, giving rise to interrupted lines of fluorescence. Tyrosinated and acetylated tubulins have been reported to occur in pollen tubes (Astrom 1992;Del Casino et al 1993).…”