水稲の乾物生産に及ぼす土壌温度の影響(第1報) : 生育前期の乾物生産の特性について

The rice plants(c. v. Norin 29) grown under three different soil temperature(33℃, 28℃, and 23℃) were periodically sampled to examine the dry weight of the top and root, and the leaf area per plant, for the growth duration from transplanting to heading stage.
Reults obtained were as follows ;
1. The larger growth of the top and root was recognized in 33℃ and 28℃ plants, in the tillering stage, but after that the growth of 33℃ plants was depressed.
2. The ratio of top to root dry weight was higher in plants under 28℃ in this growth duration.
3. The leaf area per plant was larger in plants under higher soil temperature. And in the tillering stage a positive correlation between soil temperature and leaf area per plant was seen, but not such correlation was seen after the tillering stage.