New opportunities for plant water economy through the interaction of CO2 environment and nutrient status

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02328
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 41050:Environmental agriculture-related
• Research Institution: Nagoya University
• Principal Investigator: Yano Katsuya 名古屋大学, 生命農学研究科, 准教授 (00283424)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 高CO2環境 / 水利用効率 / 蒸散 / 窒素 / リン / カリウム

Outline of Final Research Achievements

The study demonstrated that under doubled CO2 concentrations, CO2 uptake is possible even at low stomatal aperture, and that biomass production capacity can be doubled without an increase in transpiration. However, it is more important than ever to control the nutritional status of plants in order to achieve this, and it was clarified that the supply of nitrogen, phosphorus, and potassium, whose demand is increasing, without excess or deficiency, leads to an increase in water use efficiency, which is directly related to biomass production capacity. The study also suggested that a high CO2 environment suppresses daytime transpiration but not nighttime transpiration, and that nighttime transpiration without photosynthesis includes wasteful water consumption that is not directly related to biomass production, and that suppression of such transpiration may reduce water consumption without reducing biomass production.

Free Research Field

環境農学

Academic Significance and Societal Importance of the Research Achievements

植物のバイオマス生産能は蒸散量と水利用効率の積で表現でき、蒸散量・水利用効率あるいはその両方の増加がバイオマス生産能を向上させる。ただし、バイオマス生産能と水利用効率の間には負の相関関係が成立する場合が多いため、蒸散量の増加が重要とされてきた。これに対して本研究では、この従来の考え方が現在の相対的に低いCO2濃度では成立しても、CO2濃度が上昇する将来では必ずしも成立しない可能性を示した。高CO2環境下では水利用効率が増加しやすくなるが、この水利用効率増加が栄養状態（リン・カリウム・窒素）に強く依存すること、そして利用効率の増加が植物のバイオマス生産能をに直結しやすいことを明らかにできた。