Tissue culture plantlets of Saintpaulia ionantha and Peperomia grisco-argenta were grown for 120 days in growth boxes placed in a greenhouse. The filtercovered tops of the boxes were sloped facing south, the direction of the sun, while the walls were constructed of white styrofoam board Four types of light filters covered the frames. Two blue celluloid sheets were used to alter the sunlight spectrum: one filtered out the red (B + FR), and the other removed most of the red and far-red, FR (B - FR). Two polyethylene films were formulated as light filters and diffusers: one scattered all the transmitted light and decreased the R: FR ratio (W), while the other was neutral in respect to the sunlight spectrum and did not cause light scattering (A). Vegetative growth of Saintpaulia plants was enhanced under the light-diffusing filters, resulting in higher fresh weight and larger leaves. Saintpaulia plants flowered first under the W filter, then the A filter, and last under the B + FR filter; no flowering occurred in the absence of FR light (B - RR). There was no significant difference in the development of Peperomia plants grown under the different filters. The results are discussed in relation to plant adaptation to various environments.
Tissue culture plantlets of Saintpaulia ionantha and Peperomia grisco-argenta were grown for 120 days in growth boxes placed in a greenhouse. The filtercovered tops of the boxes were sloped facing south, the direction of the sun, while the walls were constructed of white styrofoam board Four types of light filters covered the frames. Two blue celluloid sheets were used to alter the sunlight spectrum: one filtered out the red (B + FR), and the other removed most of the red and far-red, FR (B - FR). Two polyethylene films were formulated as light filters and diffusers: one scattered all the transmitted light and decreased the R: FR ratio (W), while the other was neutral in respect to the sunlight spectrum and did not cause light scattering (A). Vegetative growth of Saintpaulia plants was enhanced under the light-diffusing filters, resulting in higher fresh weight and larger leaves. Saintpaulia plants flowered first under the W filter, then the A filter, and last under the B + FR filter; no flowering occurred in the absence of FR light (B - RR). There was no significant difference in the development of Peperomia plants grown under the different filters. The results are discussed in relation to plant adaptation to various environments.