ISHS Acta Horticulturae 440: International Symposium on Plant Production in Closed Ecosystems
THE INFLUENCE OF SPECTRAL COMPOSITION ON GROWTH AND DEVELOPMENT OF CHRYSANTHEMUM PLANTS |
| Authors: | V.K. Reddy, N.C. Rajapakse, R.E. Young |
| Keywords: | light quality, photon flux density, phytochrome, spectral filters |
| Abstract:
The influence of spectral composition on growth and development of 'Bright Golden Anne' chrysanthemum plants was investigated by overlaying Roscolux™ colored acetate films on CuSO4 or water (control) spectral filters. Control filters did not alter spectral composition of sunlight while CuSO4 filters removed far-red (FR) wavelengths and transmitted blue (B) and red (R) wavelengths. A blue acetate (B69) film over the control filter removed R wavelengths and transmitted B and FR wavelengths, while B69 film over the CuSO4 filter removed both R and FR wavelengths, transmitting mainly B wavelengths. A red acetate (R19) film over the control filter removed B wavelengths and transmitted R and FR wavelengths, while R19 film over the CuSO4 filter removed both B and FR wavelengths, transmitting mainly R wavelengths. In general, plants grown in the presence of FR light were taller than the plants grown in the absence of FR light. Removal of FR light by CuSO4 filters reduced plant height by ≈22%. Plants grown in the absence of R light were the tallest in either CuSO4 or control filters. The removal of R light caused ≈38% height increase under CuSO4 or control filters in fall grown plants. The effect of absence of B light on plant height varied with the presence or the absence of FR light. In the presence of FR light, removal of B light resulted in a ≈16% plant height increase in the fall and an 8% height increase in the summer. In the absence of FR light, removal of B light did not have a significant effect on plant height. The results suggest that the absence of FR and the presence of R is critical for plant height reduction and that the effect of B depend on the presence or absence of FR. | |
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