EN
In Lupinus luteus L., infection occurred via the curled root hair. Bradyrhizobia penetrated its cell wall, probably by localized digestion, and then multiplied into the interior of the root hair. Some rhizobia escaped the penetration site before the host cell built a new wall around it. Escaped bacteria passed the distance to the root hair cell base, probably in the space between the cell wall and plasma membrane. At the root hair cell base, cell wall penetration and matrix escape occurred again. After escaping the matrix, rhizobia were endocytotically directed to the interior of the dedifferentiated cortex cell, and during subsequent mitosis were segregated to the proximal derivative. Thus the cell became the bacteroid tissue initial. The bacteria that remained within the penetration site were immobilized here due to the production of cell wall around them. Internalized bacteria were initially associated with large numbers of vesicles bearing cell-wall-like matrix. In abortive primordia the bacteria penetrated the cell walls of competent cells, and associations of bacteria and cell-wall-like matrix surrounded with a membrane were produced. At this stage, symbiosis was arrested and the symbiosomes were degraded. Necrosis or lysis of some primordium cells was observed.