Motility in ungerminated grass pollen: Association of myosin with polysaccharide-containing wall precursor bodies (P-particles)

Grass pollens lack a dormancy period, remaining in a partly hydrated state at maturation with the contents of the vegetative cell continuing in active motion thereafter. The polysaccharide-containing wall-precursor bodies, derived mainly from previous dictyosome activity (P-particles), move randomly throughout much of the vegetative cell, but at the apertural pole of the grain many follow tracks related to actin fibrils focused on the single aperture, Isolated P-particles are shown by immunofluorescence localization using an antimyosin antibody to be associated individually with myosin. This, together with the fact that movement in the vegetative cell is arrested reversibly by cytochalasins, indicates that their motility is actomyosin based.