Effects of Atmospheric CO2 Concentration, Phosphorus Nutrition and Night Temperature on Growth and Yield of Rice.

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Rice plants were grown in artificially illuminated growth cabinets under conditions of ambient CO2 concentration, 28/23°C, 12-hr day/12-hr night temperatures, and 3 or 300μM phosphorus in a standard nutrient solution with soil. At the 10-leaf stage, atmospheric CO2 (350 or 700μmol mol-1) and temperature (28/23 or 28/28°C) were controlled and maintained until the harvest at 40 days after heading. At 28/23°C, the high phosphorus accelerated heading by 2-3 days while the high CO2 accelerated heading only by one day. Culm and panicle lengths were not affected by high CO2, but they increased under high phosphorus. Panicle numbers were greater in both high CO2 and high phosphorus. Panicle weight increased 20 and 40% at low and high phosphorus, respectively, in the high CO2 treatments without amelioration of the harvest index (ca. 0.5) . In 28/28°C-high CO2 plot, the heading was accelerated 3-4 days and the plant weight was similar to 28/23°C-high CO2 plot, but the harvest index was lower (<0.4) than for the 28/23°C-low CO2 plot, because the dry matter was preferentially partitioned to vegetative parts, especially to roots. At elevated atmospheric CO2, the phosphorus nutrition is important to increase rice yield. Thus, under the expected climate change due to increased green-house gases, appropriate plant nutrition to control photoassimilate partitioning will be an important practice.
日本生物環境工学会の論文