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 s tate at maturation with the contents of the vegetative cell continuing in active motion thereafter. The polysaccharide-containing wall-precu rsor bodies, derived mainly from previous dictyosome activity (P-parti cles), move randomly throughout much of the vegetative cell, but at th e apertural pole of the grain many follow tracks related to actin fibr ils focused on the single aperture, Isolated P-particles are shown by immunofluorescence localization using an antimyosin antibody to be ass ociated individually with myosin. This, together with the fact that mo vement in the vegetative cell is arrested reversibly by cytochalasins, indicates that their motility is actomyosin based.