Analyze of rooting process of vegetable transplants based on relation between plant water loss and its water potential decreasing

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06327
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 41040:Agricultural environmental engineering and agricultural information engineering-related
• Research Institution: Meiji University
• Principal Investigator: Ozawa Kiyoshi 明治大学, 研究・知財戦略機構(生田), 研究推進員(客員研究員) (40360391)
• Co-Investigator(Kenkyū-buntansha): 蜷木 朋子 明治大学, 農場, 特任講師 (20759724)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: キャベツ / 生育・収量 / トマト / 水ほう症 / 葉水分保持能 / プレッシャーチャンバー / 気孔コンダクタンス / P-V Curve

Outline of Final Research Achievements

The concept of soil water and pressure curve had introduced in the leaves of cabbages grown in an open field. Their growth and yield of eight cultivars were analyzed focusing leaf water holding ratio (LWHR) which is the exuded water ratio of plant upper fresh weight when the plant outer pressure increase from 6 bars to 8 bars in the pressure chamber.
The wilting on 4 DAT was in the positive relation with LWHR. However, the growth after that day was in the negative relation with LWHR, and stomatal conductance (Cs). Head weight could be estimated by the equation "Head weight = Days until harvest / (LWHR X Cs)". The result was reverse relation with the normal understandings,

Free Research Field

作物環境制御

Academic Significance and Societal Importance of the Research Achievements

葉が保持する水の量と大気が水を引出す圧力との関係は、P-V Curveとして知られている。これまで水ストレスを受ける圧力範囲での葉水分保持率が高いことが耐乾性の向上に有利なことが森林生態学で解明されている。この概念を高温期に定植するキャベツに適用したところ、定植7日後の萎凋は予想通りに葉水分保持率の高い品種で少なかった。しかし、その後の生育は、葉水分保持率だけでなく気孔コンダクタンスも、低い品種ほど生育が優れるという従来と逆の知見が得られた。これらの品種では、午前に比べて午後に蒸散が少なかった一方で、曇天が多かった期間の生育は劣った。P-V Curveの重要性を今後の研究で訴え続けたい。