Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States

To investigate whether blue-dominant spectra from end-of-day (EOD) lighting can regulate crop morphological and flowering responses, chrysanthemum (<i>Chrysanthemum × morifolium</i>; obligate short day), geranium (<i>Pelargonium × hortorum</i>; day neutral), calibrachoa (<...

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Main Authors: Yun Kong, Qingming Li, David Llewellyn, Youbin Zheng
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/7/1649
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author Yun Kong
Qingming Li
David Llewellyn
Youbin Zheng
author_facet Yun Kong
Qingming Li
David Llewellyn
Youbin Zheng
author_sort Yun Kong
collection DOAJ
description To investigate whether blue-dominant spectra from end-of-day (EOD) lighting can regulate crop morphological and flowering responses, chrysanthemum (<i>Chrysanthemum × morifolium</i>; obligate short day), geranium (<i>Pelargonium × hortorum</i>; day neutral), calibrachoa (<i>Calibrachoa × hybrida</i>; facultative long day), and gerbera (<i>Gerbera jamesonii</i>; facultative short day) plants were grown under different light-emitting diode (LED) spectrum treatments from January to April 2020, in Guelph, Canada. The spectrum treatments were (1) no EOD lighting, (2) narrowband blue from LEDs (B), (3) a combination of narrowband blue, red, and far-red LEDs with a photon flux ratio of 47:3:1 (blue:red:far-red; BRFR). The B and BRFR treatments ran daily from 0.5 h to 4.5 h after dusk. Compared to the control without EOD lighting, chrysanthemum flower initiation was completely inhibited under BRFR. Flowering time was slightly delayed, but flower bud number increased under B. Side branch number, leaf area, and main stem length and diameter increased under B and BRFR. In the geranium B and BRFR did not affect flowering, but increased side branch number and length and diameter of the main stem. Both spectrum treatments promoted earlier flowering in the calibrachoa, but BRFR produced more flower buds. The calibrachoa aerial dry biomass and main stem length increased under B and BRFR. The gerbera leaf chlorophyll index and leaf thickness increased under BRFR. Both spectrum treatments increased the gerbera flower bud size, despite having little effect on flowering time. In all species, at least one of the LED treatments increased canopy size. Therefore, low levels of B or BRFR can be potentially used for EOD lighting to regulate the flowering and morphology of potted ornamentals.
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spelling doaj-art-1af035fab35c4d82975dc3fec3cbfc822025-08-20T03:32:31ZengMDPI AGAgronomy2073-43952025-07-01157164910.3390/agronomy15071649Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary StatesYun Kong0Qingming Li1David Llewellyn2Youbin Zheng3School of Environmental Sciences, University of Guelph, Guelph, ON NIG 2W1, CanadaSchool of Environmental Sciences, University of Guelph, Guelph, ON NIG 2W1, CanadaSchool of Environmental Sciences, University of Guelph, Guelph, ON NIG 2W1, CanadaSchool of Environmental Sciences, University of Guelph, Guelph, ON NIG 2W1, CanadaTo investigate whether blue-dominant spectra from end-of-day (EOD) lighting can regulate crop morphological and flowering responses, chrysanthemum (<i>Chrysanthemum × morifolium</i>; obligate short day), geranium (<i>Pelargonium × hortorum</i>; day neutral), calibrachoa (<i>Calibrachoa × hybrida</i>; facultative long day), and gerbera (<i>Gerbera jamesonii</i>; facultative short day) plants were grown under different light-emitting diode (LED) spectrum treatments from January to April 2020, in Guelph, Canada. The spectrum treatments were (1) no EOD lighting, (2) narrowband blue from LEDs (B), (3) a combination of narrowband blue, red, and far-red LEDs with a photon flux ratio of 47:3:1 (blue:red:far-red; BRFR). The B and BRFR treatments ran daily from 0.5 h to 4.5 h after dusk. Compared to the control without EOD lighting, chrysanthemum flower initiation was completely inhibited under BRFR. Flowering time was slightly delayed, but flower bud number increased under B. Side branch number, leaf area, and main stem length and diameter increased under B and BRFR. In the geranium B and BRFR did not affect flowering, but increased side branch number and length and diameter of the main stem. Both spectrum treatments promoted earlier flowering in the calibrachoa, but BRFR produced more flower buds. The calibrachoa aerial dry biomass and main stem length increased under B and BRFR. The gerbera leaf chlorophyll index and leaf thickness increased under BRFR. Both spectrum treatments increased the gerbera flower bud size, despite having little effect on flowering time. In all species, at least one of the LED treatments increased canopy size. Therefore, low levels of B or BRFR can be potentially used for EOD lighting to regulate the flowering and morphology of potted ornamentals.https://www.mdpi.com/2073-4395/15/7/1649flower initiationflower budsleaf traitlight spectrumphotoperiod responseside branching
spellingShingle Yun Kong
Qingming Li
David Llewellyn
Youbin Zheng
Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States
Agronomy
flower initiation
flower buds
leaf trait
light spectrum
photoperiod response
side branching
title Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States
title_full Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States
title_fullStr Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States
title_full_unstemmed Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States
title_short Flowering and Morphology Responses of Greenhouse Ornamentals to End-of-Day Blue-Dominant Lighting with Different Phytochrome Photostationary States
title_sort flowering and morphology responses of greenhouse ornamentals to end of day blue dominant lighting with different phytochrome photostationary states
topic flower initiation
flower buds
leaf trait
light spectrum
photoperiod response
side branching
url https://www.mdpi.com/2073-4395/15/7/1649
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AT davidllewellyn floweringandmorphologyresponsesofgreenhouseornamentalstoendofdaybluedominantlightingwithdifferentphytochromephotostationarystates
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