Pollen Tube Growth in Culture. I. Control of Morphology and Generative Nucleus Division in Cultured Pollen Tubes of Nicotiana

Abstract

Pollen tubes are undoubtedly interesting cells. They are unusual in growing by tip-extension, with an ordered zonation of organelles, and are one of the few types of differentiated higher-plant cell that can be grown successfully in single-cell culture. Cultured pollen tubes thus form excellent material for studying the fundamental mechanism of tip-growth (Vasil 1987; Steer áSteer, 1989), the metabolic pathways of individual cells, and cell wall deposition and maturation. The pollen tube is unusual in containing the (1«3)$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{}$linked glucan, callose, in its walls and septa (plugs) without being wounded, and we are thus using pollen-tube membranes to study the control of callose biosynthesis. Lastly, the pollen tube is the male gametophyte, and in many species bears the receptor for the pistil self-incompatibility (SI) product (Haring et al., 1990); pollen tubes can therefore be used in bioassays for SI (Jackson áLinskens, 1990).