Alternating Red/Blue Light Increases Leaf Thickness and Mesophyll Cell Density in the Early Growth Stage, Improving Photosynthesis and Plant Growth in Lettuce

• OHTAKE Noriko

  Green Project, Institute for Integrated Product Development, Showa Denko K. K.,

• JU Yao

  Green Project, Institute for Integrated Product Development, Showa Denko K. K.,

• ISHIKURA Masaharu

  Green Project, Institute for Integrated Product Development, Showa Denko K. K.,

• SUZUKI Hiroshi

  Green Project, Institute for Integrated Product Development, Showa Denko K. K.,

• ADACHI Shunsuke

  College of Agriculture, Ibaraki University

• YAMORI Wataru

  Institute for Sustainable Agro-Ecosystem Services, Graduate School of Agricultural and Life Sciences, The University of Tokyo

Abstract

Numerous studies in plant factories show that alternating irradiation of red and blue (R/B) light promotes growth of leafy lettuce compared with simultaneous R+B (RB) light or white (W) light, even under the same daily light integrals. Here we investigate why alternating R/B light enhances lettuce growth in terms of the anatomical and photosynthetic changes in leaves. At 16 days after sowing (DAS), plants under alternating R/B light for 12/12 hours (R12/B12) had higher leaf thickness, mesophyll cell density, and leaf mass per area than did plants under RB light for 24 hours (RB24) or W light for 24 hours (W24). At 35 DAS, these anatomical values of leaves and the daily carbon gain of leaves evaluated by gas exchange analysis were higher under R12/B12 than under W24, and were similar to RB24. The projected leaf area and maximum leaf length were highest under R12/B12 across all growth stages, which would promote light capture. Marketable fresh weight under R12/B12 at 35 DAS was highest among the treatments. These results indicate that leaf morphological changes affecting the light absorption efficiency and photosynthetic rate could be the primary factors of enhanced lettuce production under the alternating R/B light condition.

Journal

• Environment Control in Biology

  Environment Control in Biology 59 (2), 59-67, 2021-04-01

  Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists

Keywords

• lettuce
• light-emitting diodes
• mesophyll
• photosynthesis
• plant factory

Details

• CRID: 1390569324549379328
• NII Article ID: 130008031277
• NII Book ID: AA12029220
• DOI: 10.2525/ecb.59.59
• ISSN: 18830986
• ISSN: 1880554X
• NDL BIB ID: 031420125
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I031420125
• Web Site: https://www.jstage.jst.go.jp/article/ecb/59/2/59_59/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed