The chemiluminescence (CL) of rice (Oryza sativa L.) seeds at different temperatures and the CL spectra of rice seed, caryopses and seed coat were studied during early imbibition. Compared with the CL of barley (Hordeum vulgare L.) and soybean (Glycine max L. Merr.) seeds, the CL of rice seeds had a non-linear, logarithmic-like increase of intensity in the temperature range 30-50 degrees C. The Van't Hoff coefficient Q(10) = I(T+10)/I(T) was equal to 2. The emission spectrum of whole rice seed, rice and coat had a greater proportion of red light during early imbibition, which led to the conclusion that the CL of rice seed during early imbibition arises partially from enzyme-catalysed reactions.