Studies on the Effect of the Relative Humidity of the Atmosphere on the Growth and Physiology of Rice Plants : VIII. Effect of ambient humidity on dry matter production and nitrogen absorption at various temperatures

The effect of relative humidity (RH) on the dry matter production and nitrogen absorption of rice seedlings (age in leaf mumber of 5) was investigated. Plants were grown for 4 days under 60 or 90% RH at 12-hr day/12-hr night temperatures of 24/20, 28/24, 32/28 and 36/32°C. 1. Dry matter increase of leaves and roots in the plants grown at 90% RH was higher at 24/20 and 28/24°C, but lower at 32/28 and 36/32°C than that of the plants grown in 60% RH. 2. Nitrogen absorption and content of heavy nitrogen of leaves and roots in the plants grown at 90% RH were also higher at 24/20 and 28/24°C, but lower at 32/28 and 36/32°C than those of the plants grown in 60% RH. These results indicate that dry matter increase and nitrogen absorption of rice seedlings are affected by humidity and temperature, with highly significant correlations.