【Abstract】 With highly infective activity, and the production and role of reactive oxygen species (ROS) in Laminaria japonica Aresch against infection by five strains of alginic acid decomposing bacteria were investigated. The results were as follows: 1. The production of reactive oxygen species in L. japonica during infection of alginic acid decomposing bacteria was an universal response. 2. The massive production of reactive oxygen species occurred only at early stage of infection and decreased gradually accompaning with the decrease of photosynthesis. 3. The notable decline of ROS production occurred earlier than that of photosynthesis. 4. The rate of production of ROS at early infective stage was related to the resistance of L. japonica against infection.更多还原