Invasion of plant tissue in the rumen by the flagellate Neocallimastix frontalis.

The flagellate stage of the rumen phycomycete Neocallimastix frontalis invades and germinates on plant material in the rumen and in vitro, preferentially invading the lemmas, paleas, awns and flower bracts in members of the plant family Gramineae, and flower bracts in certain of the Papilionaceae. The principal sites of invasion were the stomata and damaged tissue, through which penetration of the plant tissue by the rhizoid of the germinating cell occurred. Subsequent growth of the vegetative stage occurred with the uptake of 14C from 14C-labelled plant tissue. Host diets rich in seed-head material normally supported higher population densities of N. frontalis in the rumen even though the dry matter digestibilities of these diets were lower.