Effect of timing of water fall, re-irrigation and water stress on photosynthetic capacity of individual rice leaves

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15944
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 41040:Agricultural environmental engineering and agricultural information engineering-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Tatsumi Kenichi 東京農工大学, (連合)農学研究科(研究院), 准教授 (40505781)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 作物モデル / 光合成 / 落水 / 再潅水 / 水ストレス / イネ

Outline of Final Research Achievements

To evaluate the effects of timing of water fall and re-irrigation and water stress level on photosynthetic capacity of individual rice leaves, and to propose effective water management, we conducted a growth survey, gas exchange measurement, and yield survey of rice plants in four treatments of water stress and fertilizer stress at Phytotron. The results showed that: 1) the original fertilizer determines plant height, biomass growth rate, and the number of offshoots; 2) water stress suppresses photosynthetic activity, and ear emergence during water stress is dependent on the use of assimilated substances stored before the stress period; 3) the degree of effect of water stress depends on the growth period and stage, and the effect of water stress before the ear emergence stage is relatively low. 3) The degree of effect of water stress varies depending on the growth period and stage, and water stress relatively does not suppress ear emergence before the ear emergence stage.

Free Research Field

農業情報気象学

Academic Significance and Societal Importance of the Research Achievements

水ストレス下での栽培において，元肥を抑制して，分げつ数を減らし，出穂期前に間断灌漑を実施することで水利用効率，窒素利用効率を高めた資源節約型の水稲栽培が可能となる．また，イネ個葉の光合成能力を調べるにとどまらず，実際の水田圃場への適用を通じて得られる検証結果をもとに，気象・水・土壌がイネ生産性に与える複合影響の農業現場での応用が可能な高汎化型モデルの実現・確立を視野に入れている．以上，農学と情報科学の協合的発展を目指す点においても各専門分野でこれまで提示されてこなかった点で学術的意義や社会的意義がある．