Author(s)

Atsushi Motogaito^1,2,3, Naoki Hashimoto¹, Kazumasa Hiramatsu^1,2, Katsusuke Murakami⁴

¹Graduate School of Engineering, Mie University, Tsu, Japan.
²The Center of Ultimate Technology on Nano-Electronics, Mie University, Tsu, Japan.
³Iga Regional Satellite Campus, Mie University, Iga, Japan.
⁴Graduate School of Bioresources, Mie University, Tsu, Japan.

In plant cultivation, the number of photons is more important than the light energy from the chemical reactions that occur during photosynthesis. In addition, the blue and red photon flux (B/R) ratio is an important parameter for plant cultivation. Here we discuss the effect of the spectral irradiance distribution and the B/R ratio on plant cultivation. We cultivated lettuce seedlings, Lactuca sativa L. Cv. Okayama, using a light-emitting diode illumination system that can precisely control the spectral irradiance distribution and B/R ratio. The B/R ratio varied from 0.36 to 2.06 according to the intensity of the blue light when the photosynthetic photon flux density values were sufficient to ensure the 150 - 200 μmol⋅m⁻²⋅s⁻¹. High photon flux densities of blue light result in reduced plant length, plant height, and leaf area, thereby suggesting its role in the suppression of leaf growth. Therefore, we conclude that a lower photon flux of blue light (B/R Ratio) is optimal for lettuce cultivation.

Plant Cultivation, LED Lighting, Blue and Red Photon Flux (B/R) Ratio

Motogaito, A. , Hashimoto, N. , Hiramatsu, K. and Murakami, K. (2017) Study of Plant Cultivation Using a Light-Emitting Diode Illumination System to Control the Spectral Irradiance Distribution. Optics and Photonics Journal, 7, 101-108. doi: 10.4236/opj.2017.76010.