Pollen-stigma interaction in grasses: a brief review

Abstract

The grasses are unusual among flowering plants in having rapid pollen germination on the stigma and a subsequent rapid rate of tube growth. This, and the structural simplicity of the stigma tissues, makes them apt subjects for the investigation of pollen-pistil interactions. Several aspects of these interactions are reviewed, including (a) the hydrodynamics of pollen in the period immediately preceding germination; (b) the responses of stigma cells to pollen contact; (c) the function of intine-held proteins during germination and the organisation of the pollen tube tip; (d) cuticle penetration; (e) tube growth, wall synthesis, and enzyme emission; and (0 the cytology and cytochemistry of the transmitting tract. Some features of the physiology of incompatibility systems in wild and cultivated grasses are discussed.