Organization of the cytoskeleton in pollen tubes ofPyrus communis: a study employing conventional and freeze-substitution electron microscopy, immunofluorescence, and rhodamine-phalloidin

Microtubules and microfilaments are both responsible for pollen tube elongation in the coniferPicea abies (Norway spruce)

“…In angiosperms, there is also evidence that microtubules and microfilaments colocalize in the tube (Franke et al 1972, Lancelle et al 1987, Raudaskoski et al 1987, Tiwari and Polito 1988, Lancelle and Hepler 1991. However, comparative studies evaluating whether microtubule disruptors affect microfilaments, and vice versa, have not been reported.…”

Pollen and Stigma Structure and Function: The Role of Diversity in Pollination

“…Whether tubes emerge on a dry stigma surface, from a grain submerged in stigma exudates, or from pollen germinated in vitro, the grain organizes its cytoplasm and cytoskeleton to support the extension of a single tube. These changes occur within minutes after hydration and include the formation of filamentous cytoskeletal structures that wrap around the nuclei, actin cytoskeleton polarization toward the site of tube emergence (Tiwari and Polito, 1988;Heslop-Harrison and Heslop-Harrison, 1992), reorientation of the large vegetative nucleus so that it enters the extending tube before the generative cells (Heslop-Harrison et al, 1986a;Heslop-Harrison and Heslop-Harrison, 1989;Lalanne and Twell, 2002), assembly of mitochondria and polysaccharide particles at the site of the elongating tube tip (Cresti et al, 1977(Cresti et al, , 1985Mazina et al, 2002), and selection of the pollen plasma membrane for secretory vesicle targeting and deposition of callose (b-1!3 glycan) at the site of tube emergence (Johnson and McCormick, 2001).…”

The Cotton ACTIN1 Gene Is Functionally Expressed in Fibers and Participates in Fiber Elongation

“…It has been reported that F-actin plays an important role in pollen tube growth (Mascarenhas, 1993;Chen et al, 2002), in trichome morphogenesis (Mathur et al, 1999), in root hair tip growth (Miller et al, 1999), and in cell elongation of other cell types (Baluska et al, 2000;Waller et al, 2002;Yamamoto and Kiss, 2002). In the tip-growing pollen tube, F-actin arrays are very dynamic, changing from large spherical bodies to F-actin bundles oriented predominantly parallel to the growth axis (Tiwari and Polito, 1988). Similar F-actin arrays were also found for root hair growth (Miller et al, 1999) as well as root tip growth (Blancaflor and Hasenstein, 1997).…”