RED/FAR-RED PHOTON FLUX RATIO USED AS AN INDEX NUMBER FOR MORPHOLOGICAL CONTROL OF PLANT GROWTH UNDER ARTIFICIAL LIGHTING CONDITIONS

The red/far-red (R/FR) photon flux ratio is an important index of morphological control of plant growth.

Both 600–700/700–800nm and 655–665/725–735nm have been used as definitions for R/FR. In our research, these two definitions were tested comparing the growth of sunflowers using 3-band+FR fluorescent lamps and metal halide lamps at the same of R/FR and photosynthetic photon flux density.
The ratio, 600–700/700–800nm, was a better index for morphological characteristics.
Plant shape and morphological characteristics were surprisingly similar in spite of the different spectral distributions.

III International Symposium on Artificial Lighting in Horticulture

K. Murakami, I. Aiga, K. Horaguchi, M. Morita

phytochrome photoequilibrium, wave band, sunflower, metal halide lamp, fluorescent lamp

https://doi.org/10.17660/ActaHortic.1997.418.18