水稲の乾物生産に及ぽす土壌温度の影響(第2報) : 光合成特性について

The changes of photosynthetic rate and dry matter production in rice plants (c. v. Norin 29) grown under different soil temperature (23℃ and 33℃) for the growth duration from maximum tiller number stage to heading stage have been investigated.
The following results were obtained ;
1. Both photosynthetic rate per plant and per unit leaf area were higher in plants under higher soil temperature.
2. RGR is determined by NAR and LAR. RGR of 33℃ plants was lower and parallel to NAR. NAR in this duration is said to be associated with photosynthetic rate of a rice community. It seemed that 33℃ plants had low photosynthetic rate of a rice community.
3. 33℃ plants had larger leaf area per plant and narrow, thin leaves. They seemed to have low light-receiving coefficient.
4. Higher soil temperature made photosynthetic rate per plant and per unit leaf area higher, but in the other hand, light-receiving coefficient lower. Then photosynthetic rate of a rice community may be lower and dry matter production may be depressed in plants under higher soil temperature, in this experiment duratron.