Differences between Rice and Wheat in the Temperature Responses of Photosynthesis and Plant Growth

Abstract

We examined the differences in the effects of temperature on photosynthesis and plant growth between rice and wheat. The optimal temperatures of photosynthesis were 30 to 35C in rice and 25 to 30C in wheat, respectively. These were not affected by growth temperatures except rice grown at 19/16C and wheat grown at 13/10C, which showed a relatively higher rate of photosynthesis at lower temperature. Whereas NAR in rice decreased at low temperature (19/16C), NAR in wheat decreased at high temperature (37/31C). These declines in NAR led to decreases in the relative growth rates (RGR) in both species. A species-dependent correlation was found between NAR and RGR in each species. The results indicate that photosynthesis in rice is more adaptive for high temperature than in wheat and that difference in temperature responses of NAR between two species mainly leads to a difference in growth rate.