環境に対する水稲の生育反応 第5報 温度と空気湿度,光の強さの組合わせに対する反応

抄録

Norin-17 rice plants were grown in 4 growth cabinets (day-night temperatures, 30-25°, 25-20°, 20-15°, 15-10°C), combined with SL (strong light; natural daylight plus a 5000f.c. lamp), WL (weak light; covered by a vinyl blind having 1/3intensity of natural light), HH (high air-humidity, 70-80%R.H.) and LH (low humidity, 50-60%R.H.). The growth such as plant height, leaf appearance rate, leaf number, and dry weight all increased as temperature increased, with a higher leaf-blade ratio and T/R ratio. Concentrations of both nitrogen and carbohydrate increased as temperature decreased, especially so of the former at leaf-blade in protein-N, at leaf-sheath plus stem in soluble-N, and markedly so of the latter at leaf-sheath plus stem in crude starch. Growth was promoted slightly by HH with a higher T/R ratio and a greater accumulation of nitrogen. SL very much increased dry matter, nitrogen and carbohydrate accumulations especially so at higher temperatures, although with a decrease of leaf-blade ratio and T/R ratio.