Gas Exchange Characteristics in Rice Leaves Grown under the Conditions of Physiologically Low Temperature and Irradiance

The photosynthetic rate measured at 20°C was higher in ricegrown under 20/18°C day/night temperature and 350 µmoIquanta m^–2s^–1 than in rice grown under 25/20°Cand 1,000 µmol quanta m^–2s^–1, whereas therewas no difference in the photosynthetic rate measured at 25°Cbetween rice grown in these two ways. This difference was suggestedto be caused by an enhanced ribulose-l,5-bis-phosphate-regenerationcapacity in the low-temperature/ir-radiance-grown rice. (Received July 14, 1998; Accepted September 25, 1998)