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  • Author or Editor: Nihal C. Rajapakse x
  • HortTechnology x
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The role of light quality on growth, flowering, and postharvest characteristics of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) was evaluated in two growing seasons using 4% CuSO4 and water (control) as spectral filters. The CuSO4 filter significantly reduced plant height and internode length. However, the height reduction was smaller in the 1994-95 season (9%) than in the 1995-96 growing season (32%). The number of days to flower bud appearance and flower opening, and the number and diameter of flowers were not significantly affected by the spectral filters in either season. The CuSO4 filters reduced flower longevity by 3 days in nonstored plants, and by 5 days when plants were subjected to 1 week storage at 4 °C prior to placing in the postharvest room. Results suggest that spectral filters are effective in controlling height and producing compact Easter lily plants without causing a delay in flowering or reducing number of flowers per plant but flower longevity can be adversely affected.

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The role of light quality on growth, flowering, and postharvest characteristics of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) was evaluated in two growing seasons using 4% CuSO4 and water (control) as spectral filters. The CuSO4 filter significantly reduced plant height and internode length. However, the height reduction was smaller in the 1994-95 season (9%) than in the 1995-96 growing season (32%). The number of days to flower bud appearance and flower opening, and the number and diameter of flowers were not significantly affected by the spectral filters in either season. The CuSO4 filters reduced flower longevity by 3 days in nonstored plants, and by 5 days when plants were subjected to 1 week storage at 4 °C prior to placing in the postharvest room. Results suggest that spectral filters are effective in controlling height and producing compact Easter lily plants without causing a delay in flowering or reducing number of flowers per plant but flower longevity can be adversely affected.

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Plant response to photoselective plastic films with varying spectral transmission properties was tested using lisianthus (Eustoma grandiflorum) `Florida Pink', `Florida Blue', and `Florida Sky Blue'. Films were designated YXE-10 (far-red light-absorbing film) and SXE-4 (red light absorbing film). Light transmitted through YXE-10 films reduced plant height compared to control plants by 10% (`Florida Blue'), and stem dry weight by 19% to 40%, but the response varied by cultivar. Internode length was reduced by 10% to 19% when `Florida Pink' and `Florida Sky Blue' plants were grown under YXE-10 films. Leaf and root dry weights were not affected by YXE-10 films, with the exception that `Florida Sky Blue' plants had a lower leaf dry weight than the control plants. Light transmitted through SXE-4 films increased plant height of `Florida Pink' plants by 15% but not of `Florida Blue' or `Florida Sky Blue.' Regardless of cultivar, dry weight of leaf, stem and root tissue was not affected by SXE-4 films as compared to control films. The average number of days to flower and bud number were not affected by YXE-10 or SXE-4 films, regardless of cultivar. The results suggest that selective reduction of far-red wavelengths from sunlight may be an alternative technique for greenhouse production of compact plants, but the magnitude of the response is cultivar specific.

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The interest in using nonchemical alternatives for growth control of horticultural crops has recently increased due to public concerns for food safety and environmental pollution. Several research teams around the world are investigating alternative growth control measures, such as genetic manipulation, temperature, water and nutrient management, mechanical conditioning, and light quality manipulation. This review discusses the recent developments in light quality manipulation as a nonchemical alternative for greenhouse plant height control.

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