Abstract
Generally, the origin of the root nodule of peanut plant develops in the cortex at the base of the lateral root. According to this investigation, it was found that there was no connection between the location of root nodules and the radiating direction of the protoxylem in the central cylinder of the lateral root. The process of the infection of root nodule bacteria may be divided as follows. (1) Infection through epidermis {root hairs. other epidermal cells.} (2) Infection through broken epidermis {broken epidermis caused by the lateral root. other broken epidermis.}
