Abstract
Dyestuffs, which have the particular characteristics of being able to intercept the red (R) or far-red (FR) region, were added to clear PMMA (poly-methyl methacrylate) covering materials. Adjusting the R/FR photon flux ratio of natural radiation, these covering materials, to control the elongation of plant growth, were trial-produced. Increasing the concentration of dyestuffs, the R or FR areas are gradually largely intercepted. When a photosynthetic photon flux transmittance of 75% was decided on, R/FR ratios adjusted by these dyestuffs were calculated at 0.55 and 2.1 while that of CIE standard illuminant D65 is 1.08. Two kinds of colored plastic panes of PMMA materials were produced by mixing dyestuffs into clear PMMA of 93% transmittance. The PPF transmittance of produced PMMA named R-interceptor and FR-interceptor was 69% and 70%, respectively. The R/FR ratio of R-interceptor and FR-interceptor was 0.55 and 1.57, respectively. These materials, which are able to control plant photomorphogenesis by adjusting R/FR ratio under natural radiation could be used effectively as special covering materials for horticultural plant production.
