Selection of Cut Flower Species Affected Promotion of Flowering And

Horticultural Science (Prague), 47, 2020 (3): 169–179 Original Paper https://doi.org/10.17221/174/2018-HORTSCI

Selection of cut flower species affected promotion of flowering and stem elongation by far-red lighting or heating treatments on end of day under limited sunshine from autumn to winter

Yoshihiro Takemura1*, Masayuki Kishimoto2, Fumio Tamura1

1Faculty of Agriculture, Tottori University, Koyama, Tottori, Japan 2Tottori Prefectural Agriculture and forest Research Institute, Horticultural Experiment Center, Hokuei, Tottori, Japan *Corresponding author: [email protected]

Citation: Takemura Y., Kishimoto M., Tamura F. (2020): Selection of cut flower species affected promotion of flowering and stem elongation by far-red lighting or heating treatments on end of day under limited sunshine from autumn to winter. Hort. Sci. (Prague), 47: 169–179.

Abstract: The effect of a brief exposure to treatments of end-of-day (EOD) far-red (FR) light and EOD-heating on -flo wering and stem elongation in certain species cultivated in areas with limited sunshine from autumn to winter has been investigated. Thirteen EOD-FR treated cultivars among all 24 cultivars tested in experiment 1, showed earlier flowering than control plants. Additionally, Kanzaki No.21, F1 Winter cherry and Gypsy deep rose were earlier to flower under the all night-FR treatment than under the EOD-FR treatment. Further, 13 cultivars among all cultivars tested in experiment 1 showed greater stem length, whereas 16 cultivars of them showed greater mean internode length than controls when treated with EOD-FR. The days to flowering in 13 cultivars treated by EOD-Heating, flowering was earlier than in controls. Also, stem length and mean internode length were also promoted by the same treatment in 7 cultivars. Additionally, flowering and stem elongation of Stella rose, Arizona sun, Suzuhime and Extra carmine rose were promoted by a combination of both treatments, and productivity and quality were improved. These results suggest that the treatments tested can help the production of cut-flowers in areas with limited sunshine from autumn to winter, although the method of application of the treatments must be optimized for each species.

Keywords: EOD; FR; flowering days; stem length

Field production of cut flowers depends on natu- used for promoting flowering and stem elongation ral conditions of light and temperature that pro- of plants. However, many cultivars do not respond mote flowering and stem elongation. Thus, low consistently to plant growth regulator application light intensity and low temperature in areas with and, in many cases, species response may be highly limited sunshine from autumn to winter is a major regulator-specific. Therefore, the promotion of flow- issue when it comes to the production of photope- ering and stem elongation by environmental control riod sensitive cut flower species. In such places, a is very important for the production of cut flowers large variety of plant growth regulators are widely when many different cultivars are involved.

Supported by grants from the Project of the NARO Bio-oriented Technology Research Advancement Institution (The Special Scheme to Create Dynamism in Agriculture, Forestry and Fisheries through Deploying Highly Advanced Technology).

169 Original Paper Horticultural Science (Prague), 47, 2020 (3): 169–179

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Recently, the use of far-red (FR) light for illumina- MATERIAL AND METHODS tion treatment has received a great deal of attention as an effective means to force flowering. The most Effect of EOD- or all night- FR treatments on well-known of light receptors present in leaves are growth (Experiment 1). Twenty-four cut flower phytochromes, which are soluble pigmented pro- cultivars from 11 families as recommended culti- teins that can exist in two spectrally distinct forms var during winter in Tottori prefecture (Tables 1 (phytochromes A [phyA] and B [phyB]) and can and 2) (ESM Table S1) were grown in the Tottori sense ambient light conditions by photo intercon- Horticultural Experiment Station (35.5°N, 133.7°E) version between red (R) and FR light-absorbing for this experiment (ESM Table S2). Seeds of all forms (Furuya 1993). Additionally, the R/FR ratio cultivars were sown on August 25th, 2014 in plas- has been shown to effectively control short elon- tic germination trays with 288 cells (21 mL/cell) gation in a number species during the entire light filled with Metromix 350 (Sun Gro Horticulture phase or over a short period at EOD, with FR and Distribution Inc., USA). The seeded trays were R enhancing and reducing elongation, respectively kept in a dark cool-room at 18 °C. When seedlings (Kasperbauer, Peaslee 1973; Gilbert et al. 1995). reached leaf overlapping stage within cultivars they In addition, the acceleration of flowering by illumi- were transplanted into polyethylene pots (9 cm di- nation with a low R/FR ratio has recently been de- ameter, 7.6 cm deep) filled with chaff, Kanuma scribed in a wide range of long-day plants, including and Akadama soil mixture, peat moss, and perlite Arabidopsis (Hori et al. 2011), Eustoma grandiflo- at a ratio of 1 : 1 : 1 : 1 (v/v). Afterwards, the pots rum R. (Sato et al. 2009), and Gypsophila panicu- were transferred to a greenhouse to grow under lata (Hori et al. 2011). a constant temperature of 25 °C during the day Additionally, a new night temperature regime (08:00–17:00) and 11 °C at night (17:00–08:00). known as EOD-heating has been used on grow- Subsequently, the seedlings were treated with EOD ing flowers (Douzono et al. 2012a, b). Treatment or with all night FR light during sunset to after by EOD-heating is effective to promote flowering 3 hours, or sunrise, using emits pure far-red light under an energy-saving night temperature condi- fluorescent lamp with a peak at 740 nm (0.14 W/m2) tion. In the spray-type chrysanthemum ‘Sei-Ro- (Fuji Electric Co., Tottori, Japan) (ESM Figure S1). za’ grown under a temperature regime of 16/8 °C Control plants were grown under ambient light (light/dark period), it was shown that EOD-heating without FR treatment. treatment accelerated flower initiation and early The date of flowering was recorded in 10 plants flower bud development (Douzono et al. 2012a). from each treatment; days to flowering were defined Additionally, in the African marigold, it was report- as the number of days from planting to flowering ed that early growth and flower bud development in each cultivar. Based on the definition of flow- after flower budding were accelerated by EOD- ering in each cultivar, flowering time was defined heat treatment (Douzono et al. 2012b). On the other visually as day observed open flower of fist flower hand, little is known about the promotion of flow- in inflorescences or a single flower. At flowering, ering or stem elongation by this treatment in other each plant was collected, and the following char- cut flower plant species. Additionally, it is assumed acteristics of the cut flowers were recorded: node that cut flower species have many different culti- number of flower bud differentiation, stem length, vars that may vary widely in their response to these nude number, and plant width. Additionally, chlo- treatments. Therefore, it is important to evaluate rophyll content of five randomly selected expanded days to flowering and stem elongation in field plants leaves were measured using a chlorophyll meter to gain knowledge of the effect of these treatments. (SPAD-502 plus; Konica Minolta, Inc., Tokyo, Ja- In this study, we investigated the effect of brief pan). Statistical analysis was performed by Tukey– exposure to EOD-FR and EOD-heating treatments Kramer HSD tests using SPSS software (SPSS Sta- on flowering and stem elongation in certain pho- tistics 23.0, Chicago, USA). toperiod sensitive cut flower species grown in are- Effect of EOD- heating or -FR treatments on as with limited sunshine from autumn to winter. We growth (Experiment 2). Eighteen cut flower culti- focused on the Brassicaceae and Asteraceae, within vars from 11 families as recommended cultivar dur- which a large number of member species are culti- ing winter in Tottori prefecture (Tables 3 and 4, ESM vated as cut flowers. Table S1) were grown in the Tottori Horticultural

170 Horticultural Science (Prague), 47, 2020 (3): 169–179 Original Paper https://doi.org/10.17221/174/2018-HORTSCI

Table 1. Effect of EOD- or all night- FR treatments on the growth of long-day plants

Family Node number Mean Days to Stem length Plant width Leaf colour Genus Treatment of flower bud internode flowering (cm) (cm) (SPAD value) Cultivar differentiation length (mm) Brassicaceae Control 22a 6.0c 0.27c 26.2a 27.6a Brassica rapa EOD-FR 88b 16b 41.0b 2.56b 26.5a 31.6a Kanzaki No.21 All night-FR 84c 16b 54.7a 3.42a 23.0b 29.2a Brassicaceae Control 112a 51a 17.2b 0.34b 22.5a 60.5a Brassica oleracea EOD-FR 92b 48b 18.6b 0.39ab 23.0a 46.4a c b a a b a F1 Winter cherry All night-FR 82 48 27.0 0.56 19.5 60.3 Brassicaceae Control 107a 20a 19.2b 0.96b 24.0a 53.3a Matthiola incana EOD-FR 95b 20a 29.0a 1.45a 17.0b 48.6c Baby white All night-FR 95b 20a 30.2a 1.51a 18.5b 50.9b Brassicaceae Control 64a 13c 5.2b 0.40a 9.3b 47.6a Lobularia maritima EOD-FR 61ab 15b 5.6b 0.37a 10.4ab 49.3a Easter bonnet white All night-FR 59b 17a 6.7a 0.39a 11.8a 41.8a Asteraceae Control 115a 28a 9.8a 0.35b 34.2a 46.8a Calendula officinalis EOD-FR 115a 25b 9.9a 0.40a 33.9a 45.0a Orange gem All night-FR 115a 24b 10.5a 0.44a 34.0a 45.8a Asteraceae Control 121a 17a 9.4b 0.55b 20.0a 46.6a Bellis perennis EOD-FR 123a 13b 13.1a 1.01a 20.5a 47.0a Early pomponette red All night-FR 121a 13b 13.6a 1.05a 21.5a 46.9a Plantaginaceae Control 158a 10a 17.9a 1.79b 21.5a 40.7a Antirrhinum majus EOD-FR 151b 9b 19.6a 2.18a 20.5a 42.3a Snapshot yellow All night-FR 149b 9b 19.5a 2.17a 20.5a 44.4a Scrophulariaceae Control 124a 10a 13.3b 1.33b 26.0b 25.1a Nemesia caerulea EOD-FR 121a 9b 16.3a 1.81a 32.0a 26.4a Rapin yellow All night-FR 121a 9b 17.7a 1.97a 34.5a 31.6a

Violaceae Viola Control 115a 16a 2.2c 0.14b 13.7b 73.2a Viola tricolor EOD-FR 109b 16a 2.4b 0.15b 16.7a 62.1b Delta premium pure- b a a a a c goldenyellow All night-FR 109 16 3.2 0.20 16.1 58.1 Solanaceae Control 106a 23a 11.4b 0.50b 29.2a 46.6a Petunia hybrida EOD-FR 109a 23a 11.7b 0.51b 26.6a 45.5a Baccarat rose morne All night-FR 106a 23a 15.1a 0.66a 29.4a 55.9a Caryophyllaceae Control 146a 12a 9.4b 0.78b 20.8b – Gypsophila muralis EOD-FR 132b 11b 10.8ab 0.98a 24.5a – Gypsy deep rose All night-FR 122c 11b 11.4a 1.04a 25.0a – Caryophyllaceae Control 148a 13a 22.7c 1.75c 29.5a 41.2a Dianthus chinensis EOD-FR 127b 12b 26.0b 2.17b 26.5b 51.6a Supra purple All night-FR 127b 12b 27.6a 2.30a 26.5b 40.1a Dipsacaceae Control 162a 7a 1.3b 0.19b 12.0b 59.9a Scabiosa japonica EOD-FR 149b 6b 2.5a 0.42a 22.0a 57.1a Ritz blue imp All night-FR 146b 6b 2.3a 0.38a 21.0a 51.1a zDifferent letters indicate significant differences T among species at P < 0.05 by Tukey-Kramer’s HSD test (n = 5)

Experiment Station for this experiment. Seeds of all stant temperature of 25 °C during the day (sunrise cultivars were sown on August 25, 2014, kept in the to sunset), at 20 °C at EOD (for 3 h starting from dark cool-room and then transplanted into the same sunset) and at 11 °C at night (from the time at which pots as previously described in Experiment 1. EOD treatment ended to sunrise). Control plants The pots were transferred to a greenhouse and were grown under a constant temperature of 25 °C grown under EOD-heating treatment under a con- during the day (sunrise to sunset) and 11 °C at night 171 Original Paper Horticultural Science (Prague), 47, 2020 (3): 169–179

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Table 2. Effect of EOD- or all night- FR treatments on the growth of day-neutral or short-day plants

Family Node numb. Mean inter- Days to Stem length Plant width Leaf color Genus Treatment of flower bud node flowering (cm) (cm) (SPAD value) Cultivar differentiation length (mm)

az a a a b a Asteraceae Control 162 17 4.9 0.29 24.0 62.2 Gazania rigens EOD-FR 149b 16b 1.5b 0.09b 31.5a 56.3a F1 New day clear orange All night-FR 145b 16b 1.1c 0.07b 30.0a 60.7a a a c b b a Asteraceae Control 135 23 5.4 0.23 21.5 54.4 senecio bicolor EOD-FR 135a 22a 10.3b 0.47a 24.5a 62.2a Silver dust All night-FR 135a 22a 11.1a 0.50a 24.0a 56.3a a a b b a a Asteraceae Control 75 5 12.5 2.50 18.0 43.7 Cosmos bipinnatus EOD-FR 72b 5a 14.0ab 2.80ab 13.0b 43.0a Road orange All night-FR 71b 5a 16.2a 3.24a 12.5b 42.1a b b a a a a Asteraceae Control 115 9 19.6 2.18 41.0 35.6 Dahlia hybrida EOD-FR 133a 12a 19.2a 1.60b 30.5b 40.0a Early bird All night-FR 135a 11a 19.5a 1.77b 26.5c 32.6a a b b a a a Asteraceae Control 121 20 21.5 1.08 28.0 41.3 Helianthus annus EOD-FR 123a 23a 22.5ab 0.98a 27.5a 39.3a F1 Ballade All night-FR 123a 24a 26.6a 1.11a 25.0b 38.1a a b b b c b Asteraceae Control 88 5 14.6 2.92 13.2 30.0 Zinnia elegans EOD-FR 88a 6a 24.2a 4.03a 16.7b 39.5a Zinnita scarlet All night-FR 88a 6a 25.0a 4.17a 18.4a 37.6a a a b c b b Asteraceae Control 150 9 33.7 3.74 25.0 45.0 Ageratum houstonianum EOD-FR 130b 8b 38.6ab 4.83b 25.5b 51.6a Top blue All night-FR 127b 8b 40.3a 5.04a 27.5a 48.8a a a b a a a Balsaminaceae Control 92 16 5.2 0.33 12.0 49.5 Impatiens walleriana EOD-FR 92a 16a 6.3a 0.39a 10.5b 53.8a F1 Impureza red All night-FR 92a 16a 6.2a 0.39a 10.8b 55.9a a a c c a a Lamiaceae Control 102 8 10.2 1.28 13.0 45.1 Salvia splendens EOD-FR 88b 7b 12.0b 1.71b 14.2a 47.3a Red alert All night-FR 88b 7b 14.5a 2.07a 14.4a 43.3a Lamiaceae Control – 9a 6.0c 0.67c 14.4b 20.3a Solenostemon scutellari- EOD-FR 121a 9a 6.8b 0.76b 16.0a 22.5a oides a a a a a a Gorilla Jr. Watermelon All night-FR 121 9 7.4 0.82 17.0 21.9 a a b c a a Amaranthaceae Control 68 6 5.8 0.97 11.1 35.0 Celosia argentea EOD-FR 65b 6a 7.7a 1.28b 11.6a 34.6a Kimono scarlet All night-FR 65b 6a 8.4a 1.40a 12.2a 32.8a zDifferent letters indicate significant differences among species at P < 0.05 by Tukey-Kramer’s HSD test (n = 5)

(sunset to sunrise). Seedlings under EOD-FR width was recorded on plants from each treat- treatments during sunset to after 3 hours or sunrise ment as previously described in Experiment 1. were treated using a far-red light fluorescent lamp. Statistical analysis was performed by Tukey– The date of flowering, characteristics of the cut Kramer HSD tests and two-way analysis of vari- flowers, the node number of flower bud differ- ance (ANOVA) using SPSS software (SPSS Statis- entiation, stem length, nude number, and plant tics 23.0, Chicago, USA).

172 Horticultural Science (Prague), 47, 2020 (3): 169–179 Original Paper https://doi.org/10.17221/174/2018-HORTSCI

Table 3. Effect of EOD-heating or -FR treatments on the growth of long-day plants

Family Node numb. Mean inter- Treatment Days to Stem length Plant width Genus of flower bud node flowering (cm) (cm) Cultivar EOD-heating EOD-FR differentiation length (mm) Control 228az 46a 13.4b 0.3b 17.5a Control EOD-FR 197b 36b 31.4a 0.9a 18.5a

Control 212a 45a 15.7b 0.3b 19.0a Asteraceae EOD-heating Callistephus chinensis EOD-FR 186b 36b 35.9a 1.0a 17.0a Stella rose Heating NSy NS NS NS NS Two-way FR ** ** ** * NS ANOVA Heating and FR ** ** ** * NS

Control 213a 24b 11.6d 0.5b 25.5b Control EOD-FR 199b 22c 19.6b 0.9ab 29.5a

b a c b b Asteraceae Control 197 27 15.4 0.6 25.5 EOD-heating c d a a a Gaillardia grandiflora EOD-FR 191 19 29.7 1.6 30.0 Arizona sun Heating * * * NS NS Two-way FR * ** * * * ANOVA Heating and FR ** ** ** * *

Control 169a 36a 12.9b 0.4a 26.2b Control EOD-FR 169a 36a 19.2a 0.5a 28.5a

a b a a a Asteraceae Control 165 33 15.2 0.5 29.0 EOD-heating a b a a a Coleostephus myconis EOD-FR 165 33 14.6 0.4 31.0 Upright yellow Heating NS * * NS * Two-way FR NS NS * NS * ANOVA Heating and FR NS * * NS *

Control 184a 17a 19.0b 1.1b 33.0a Control EOD-FR 175b 16ab 21.0a 1.3ab 36.5a

b b b ab a Asteraceae Control 171 15 19.6 1.3 32.5 EOD-heating c b a a a Pericallis hybrida EOD-FR 165 15 20.5 1.4 32.0 Tear blue Heating * * NS NS NS Two-way FR * NS * NS NS ANOVA Heating and FR * * * * NS

Control 289a 28a 13.5c 0.5b 26.5a Control EOD-FR 286a 27a 19.3b 0.7ab 28.7a

b b b ab b Asteraceae Control 274 25 19.5 0.8 21.5 EOD-heating b b a a c Rudbeckia hirta EOD-FR 271 24 29.2 1.2 17.2 Tiger eye gold Heating * * ** NS * Two-way FR NS NS * NS * ANOVA Heating and FR * * ** * *

Control 253a 64a 11.3c 0.2b 15.5c Control EOD-FR 234ab 58b 17.7b 0.3ab 19.5a

a a bc b c Lamiaceae Control 244 66 15.6 0.2 14.5 EOD-Heating b b a a b Lavandula angustifolia EOD-FR 229 56 28.1 0.5 16.5 Elegance purple Heating NS NS * NS * Two-way FR * ** * * * ANOVA Heating and FR * ** * * *

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Table 3 to be continued: Effect of EOD-heating or -FR treatments on the growth of long-day plants

Family Node numb. Stem Mean Treatment Days to Plant width Genus of flower bud length internode flowering (cm) Cultivar EOD-heating EOD-FR differentiation (cm) length (mm) Control 212a 25a 60.9c 2.4c 31.5a Control EOD-FR 203b 23b 83.4a 3.6a 24.5a Campanulaceae Control 193c 20c 59.4c 3.0b 23.0a EOD-Heating c c a a a Campanula rapunculus EOD-FR 188 20 78.5 3.9 32.0 Suzuhime Heating ** * NS * NS Two-way FR * * ** * NS ANOVA Heating and FR ** * ** * NS Control 200a 9a 52.1c 5.8d 29.5b Control EOD-FR 193b 9a 55.7b 6.2c 31.0a Plumbaginaceae Control 188c 7b 51.7c 7.4b 27.0b EOD-Heating c b a a a Limonium sinuatum EOD-FR 188 7 66.7 9.5 31.0 Extra carmine rose Heating * * * * NS Two-way FR * NS ** * ** ANOVA Heating and FR * * ** * ** Control 243a 32a 89.2c 2.8b 49.5a Control EOD-FR 212c 24c 115.4a 4.8a 59.0a Apiaceae Control 233b 28b 103.4b 3.7ab 50.0a EOD-Heating d d a a a Ammi majus EOD-FR 199 23 115.0 5.0 51.5 White lace flower Heating * * * NS NS Two-way FR * * ** * NS ANOVA Heating and FR * * * * NS Control 253a 33a 17.3b 0.5b 29.0c Control EOD-FR 233c 26b 38.8a 1.5a 50.5a Febaceae Control 249b 28ab 19.6b 0.7b 33.5c EOD-Heating Lupinus polyphyllus EOD-FR 236c 26b 30.1a 1.2a 38.0b Gallery red Heating * NS NS NS * Two-way FR ** * ** ** ** ANOVA Heating and FR * * ** ** ** zDifferent letters indicate significant differences among species at P < 0.05 by Tukey-Kramer’s HSD test (n = 5); y NS, * and ** indicate non-significant, significant at P < 0.05 and significant at P < 0.01, respectively by Two-way ANOVA (n = 5)

RESULTS AND DISCUSSION treatments on the growth of each long-day cultivar tested. Among cultivars tested as long-day plant, In the field of horticultural science, EOD-FR light days to flowering in 8 EOD- FR treated cultivars treatment has been applied to numerous plant spe- (‘Kanzaki No. 21’, ‘F1 Winter cherry’, ‘Baby white’, cies as an artificial method to promote stem elon- ‘Snapshot yellow’, Delta premium puregoldenyel- gation or flowering of ornamental cut flowers, in- low’, ‘Gypsy deep rose’, ‘Supra purple’, ‘Ritz blue imp’) cluding Chrysanthemum morifolium R. (Lund et al. were less than in controls, i.e., each of these cultivars 2007), E. grandiflorum R. (Yamada et al. 2008), Antir- flowers earlier than untreated plants of the same cul- rhinum majus L. (Sumitomo et al. 2009), Helianthus tivar (Table 1). Additionally, the flowering of ‘Kan- annuus L. (Sumitomo et al. 2009), Matthiola incana zaki No. 21’, ‘F1 Winter cherry’ and ‘Gypsy deep L. (Sumitomo et al. 2009), and Cucumis sativus L. rose’ among those 8 cultivars was promoted more (Xiong et al. 2011). The present study was performed significantly by the all-night – FR treatment. These to estimate the effects of EOD- or all night- FR light results indicate that the FR treatment duration also treatment on the morphology of several cut flowers affected shortening of the days to flowering. Addi- in Experiment 1. Table 1 shows the effect of both FR tionally, the node number of flower bud differentia-

174 Horticultural Science (Prague), 47, 2020 (3): 169–179 Original Paper https://doi.org/10.17221/174/2018-HORTSCI

Table 4. Effect of EOD-heating or -FR treatments on the growth of day-neutral or short-day plants

Family Node numb. Stem Mean Plant Treatment Days to Genus of flower bud length internode width flowering Cultivar EOD-Heating EOD-FR differentiation (cm) length (mm) (cm) Control 209bz 22a 15.2b 0.7b 37.3a Control EOD-FR 217a 23a 16.2b 0.7b 33.6a

b b a a a Asteraceae Control 197 19 24.6 1.3 36.4 EOD-Heating b b a a a Gerbera jamesonii EOD-FR 198 19 28.2 1.5 38.2 Festival scarlet eye Heating * * * * NS Two-way FR * NS y NS NS NS ANOVA Heating and FR * * * * NS

Control 176a 9a 9.2a 1.0a 18.0a Control EOD-FR 172a 9a 9.2a 1.0a 17.0a

b b a a b Asteraceae Control 167 8 9.5 1.2 16.0 EOD-Heating b b a a b Tagetes erecta EOD-FR 164 8 9.1 1.1 16.5 Discovery yellow Heating ** * NS NS * Two-way FR NS NS NS NS NS ANOVA Heating and FR * * NS NS *

Control 205a 18a 25.9b 1.4d 35.5b Control EOD-FR 200a 18a 30.7a 1.7b 35.5b

Control 195b 16b 25.6b 1.6c 39.0a Campanulaceae EOD-Heating Isotoma axillaris EOD-FR 191b 17b 37.3a 2.2a 41.0a Avant-garde blue Heating ** * NS * * Two-way FR NS NS ** * NS ANOVA Heating and FR ** * ** ** *

Control 203a 10a 29.9b 3.0c 33.5b Control EOD-FR 197a 10a 32.7ab 3.3b 33.5b

b a ab b ab Geraniaceae Control 185 10 33.8 3.4 36.0 EOD-Heating b a a a a Pelargonium hortorum EOD-FR 181 10 43.1 4.3 40.0 F Horizon lavender 1 Heating ** NS NS * * Two-way FR NS NS NS * NS ANOVA Heating and FR ** NS * * *

Control 228a 15a 5.8c 0.4b 10.5b Control EOD-FR 223a 15a 8.7b 0.6a 12.5a

b b c b b Solanaceae Control 210 14 6.1 0.4 10.5 EOD-Heating b b a a a Capsicum annuum EOD-FR 207 14 9.9 0.7 12.0 Salsa red Heating * * * NS NS Two-way FR NS NS * * * ANOVA Heating and FR * * * * *

Control 235a 5a 12.0a 2.4b 17.5b Control EOD-FR 235a 5a 11.3a 2.3b 19.1a

b a a a b Apocynaceae Control 225 5 12.4 2.5 16.0 EOD-Heating b a a a a Catharanthus roseus EOD-FR 223 5 12.8 2.6 20.0 F Titan rose 1 Heating * NS NS * NS Two-way FR NS NS NS NS * ANOVA Heating and FR * NS NS * *

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Table 4 to be continued. Effect of EOD-heating or -FR treatments on the growth of day-neutral or short-day plants

Family Treatment Node numb. Stem Mean Plant Days to Genus of flower bud length internode width flowering Cultivar EOD-Heating EOD-FR differentiation (cm) length (mm) (cm) Control 169a 8a 5.2d 0.7a 11.5d Control EOD-FR 169a 8a 7.7c 1.0a 13.5c Begoniaceae Control 169a 8a 8.8b 1.0a 14.0b EOD-Heating Begonia EOD-FR 169a 8a 10.3a 1.1a 16.0a semperflorens Heating NS NS * NS * F1 Sprint red Two-way ANOVA FR NS NS * NS * Heating and NS NS * NS * FR Control 203a 14a 18.5c 1.3b 24.5c Control EOD-FR 199ab 12b 27.3a 2.3a 29.5b Control 191b 10c 25.2b 2.5a 24.0c Ranunculaceae EOD-Heating Ranunculus asiaticus EOD-FR 191b 10c 28.9a 2.9a 32.5a Mache purple Heating ** * ** * * Two-way ANOVA FR NS * * * ** Heating and FR ** * ** * ** zDifferent letters indicate significant differences among species at P < 0.05 by Tukey-Kramer’s HSD test (n = 5); yNS, * and ** indicate non-significant, significant at P < 0.05 and significant at P < 0.01, respectively by Two-way ANOVA (n = 5) tion in 6 cultivars among cultivars in which flower- to flowering in field-grown plants to gain knowl- ing was effectively promoted by the FR treatment edge on the effect by FR treatment. Additionally, was also significantly lower than in controls. The ac- the flowering of ‘Kanzaki No. 21’, ‘F1 Winter cherry’, celeration of flowering by the illumination of a low and ‘Gypsy deep rose’ under all night-FR treatment R/FR ratio has recently been described in a wide occurred earlier than under the EOD-FR treatment. range of long-day plants, including Arabidopsis These results indicate that it is suitable to prolong (Hori et al. 2011), E. grandiflorum R. (Sato et al. FR treatment duration for promoting more flower- 2009), and Gypsophila paniculata (Hori et al. 2011). ing of these cultivars. Furthermore, the flowering of all 4 cultivars belong- Further, among all long-day cultivars treated with ing to Brassicaceae plants used in this study was pro- EOD-FR, 7 cultivars (‘Kanzaki No. 21’, ‘Baby white’, moted by EOD or all-night FR treatment. ‘Early pomponette red’, ‘Rapin yellow’, ‘Delta pre- Additionally, Eustoma plants known as long-day mium puregoldenyellow’, ‘Supra purple’, ‘Ritz blue plants grown under FR light for only 3 h at the EOD imp’) showed greater stem length and mean inter- during winter showed early flower budding (Take- node length, compared with untreated plants. Also, mura et al. 2014). On the other hand, 5 cultivars ‘Kanzaki No. 21’, ‘Delta premium puregoldenyellow’

(F1 New day clear orange, Road orange, Top blue, and ‘Supra purple’ in the all-night- FR treatment Red alert, Kimono scarlet) among cultivars tested showed increased stem length and mean internode as day-neutral or short-day species also showed ear- length over the EOD-FR- treatment. In day-neutral lier flowering under EOD- or all night- FR treatment or short-day plants, among all cultivars, 6 culti- than control plants of the same species (Table 2). vars (‘Silver dust’, ‘Zinnita scarlet’, ‘F1 Impureza red’, Additionally, F1 New day clear orange, Top blue, Red ‘Red alert, Gorilla Jr. Watermelon’, ‘Kimono scarlet’) alert among those 5 cultivars showed a lower node showed increased stem length when treated with number of flower bud differentiation in EOD- or all EOD-FR, compared with untreated control plants. night-FR treatment than control plants. The promo- Stem length in 3 cultivars (‘Silver dust’, ‘Red alert’, tive effect of FR on flowering is generally observed ‘Gorilla Jr. Watermelon’) increased more under all in long-day plants, but may also be found in short- night- FR treatment, than under EOD-FR treat- day plants. Therefore, it is important to evaluate days ment. This method of promoting stem elongation

176 Horticultural Science (Prague), 47, 2020 (3): 169–179 Original Paper https://doi.org/10.17221/174/2018-HORTSCI

Takemura et al. Fig. 1

EOD-FR Control EOD-FR Control EOD-FR Control EOD-FR Control

EOD-Heating Control EOD-Heating Control

EOD-FR Control EOD-FR Control EOD-FR Control EOD-FR Control

EOD-Heating Control EOD-Heating Control

Fig. 1. Effect of a 3-h end-of-day (EOD) treatment with far red light (FR) or heating on the morphology of four cut flowers by FR light treatmentFig. 1. Eect has been o a 3- hused end- ofor several-day EOD plant treatent by brief with ar EOD-FR red light FRlight or treatment, heating on theas well as petiole, species, including tobaccoorphology (Kasperbauer o our cut lower. 1971), rad- stem elongation, and increase in GA content in Ara- ish (Proctor 1973), and soybean (Kasperbauer et al. bidopsis, bean, and spinach (Beall et al. 1996; Wu et 1984). However, the effect of EOD-FR light treat- al. 1996). High expression levels of GA20ox related ment varied among cultivars of the same species; to GA synthesis is observed in the stem of EOD- for example, EOD-FR light treatment of Chrysan- FR treatment, 3 hours after treatment in Eustoma themum cultivars for 15 min promoted stem elonga- plants (Takemura et al. 2015). Based on these previ- tion in cultivars Dekmona, Sei-elza, and Tourmalin, ous studies, we propose that the promotion of stem but it had no effect on stem elongation in cultivar elongation by FR treatment observed in this study Jimba (Sumitomo et al. 2009). Similarly, our study likely occurred by a similar reaction. showed cultivar-dependent sensitivity to FR treat- On the other hand, both FR treatments had dif- ment, although the treatment has been demonstrat- ferential effects on plant width, but little impact ed effective as a method for promoting stem elonga- on SPAD values. In long-day plants, plant width tion in many plant species. increased and decreased by EOD-FR treatments Previous studies have shown an increase of bioac- in 4 and 2 cultivars, respectively. In addition, plant tive GA content in elongating epicotyls of cowpea width increased and decreased by the same treat- 1 177 Original Paper Horticultural Science (Prague), 47, 2020 (3): 169–179

https://doi.org/10.17221/174/2018-HORTSCI ments in 4 day-neutral and 3 short-day cultivars, re- in the plants tested in this study was the lowest. spectively. In plants showing higher values of plant On the other hand, flowering and stem elongation width, it was presumed that the elongation of peti- of ‘Stella rose’, ‘Arizona sun’, ‘Suzuhime’ and ‘Extra ole length was promoted by this treatment. Addi- carmine rose’ were promoted by a combination tionally, the effect was different among cultivars. treatment, which improved productivity and qual- Petiole length of poinsettia was significantly higher ity (Figure 1). On the other hand, flowering potted under EOD-FR only in Christmas Spirit, although plants suitable a compact stem as plant form. Based Christmas Eve showed similar statistically insig- on these results, we conclude that these treatments nificant trends (Islam et al. 2014). In contrast, it can help the production of cut-flowers by reduction was presumed that plants showed lesser plant width of heating cost associated with shortening of the as a shade-avoidance response. growth period in areas with limited sunshine from Secondly, Tables 3 and 4 summarize effects on autumn to winter, although the method for the ap- growth by EOD-heating or -FR treatments in long- plication of these treatments must be optimized day plants and day-neutral or short-day plants, for each species. respectively. Among long-day cultivars, the days to flowering in 6 cultivars (‘Arizona sun’, ‘Tear REFERENCES blue’, ‘Tiger eye gold’, ‘Suzuhime’, ‘Extra carmine rose’, ‘White lace flower’) treated by EOD-Heating Beall F.D., Yeung E.C., Pharis R.P. (1996): Far-red light stimulates was lower than in control plants (Table 3). Addition- internode elongation, cell division, cell elongation, and gibber- ally, the node number of flower bud differentiation ellin levels in bean. Canadian Journal of Botany, 74: 743–752. of those 6 cultivars, was also significantly lower than Douzono M., Hisamatsu T., Ohmiya A., Ichimura K., Shibata in controls. Similarly, days to flowering and flower M. (2012a): Effect of end-of-day heating treatment in low was also promoted in 6 cultivars (‘Discovery yel- growth-temperature environment on growth and flower- low’, ‘Avant-garde blue’, ‘F1 Horizon lavender’, ‘Salsa ing in spray-type chrysanthemum. Horticultural Research red’, ‘F1 Titan rose’, ‘Mache purple’) among day- (Japan), 11: 505–513. (in Japanese). neutral or short-day cultivars by the same treat- Douzono M., Kando T., Hisamatsu T., Ohmiya A., Ichimura ment, respectively (Table 4). Additionally, the effect K., Shibata M. (2012b): Effect of end-of-day heating treat- on flowering by this treatment was also positive ment on floral initiation and development in Tagetes erecta. when applied in combination with EOD-FR treat- Horticultural Research (Japan), 11: 553–559. (in Japanese) ment. In the spray-type chrysanthemum ‘Sei-Roza’ Furuya M. (1993): Phytochromes: Their molecular species, with a controlled at 16/8 °C (light/dark period), it gene families, and functions. Annual Review of Plant Physi- was shown that EOD-heating treatment of 24 °C ology and Plant Molecular Biology, 44: 617–645. for 3 h accelerated flower initiation and early flower Gilbert I., Shavers G., Jarvis P., Smith H. (1995): Photomor- bud development (Douzono et al. 2012a). phogenesis and canopy dynamic. Phytochrome-mediated Additionally, in short-day African marigold (Tag- proximity perception accounts for the growth dynamic etes erecta L.), it was reported that early growth and of canopies of Populus trichocarpa × deltoids ‘Beaupre’. Plant flower bud development after flower budding were Cell and Environment, 18: 475–497. accelerated by heat treatment at 30 °C for 3 hours Hori Y., Nishidate K., Nishiyama M., Kanahama K., Kanayama in EOD (Douzono et al. 2012b). From these results, Y. (2011): Flowering and expression of flowering-related it was suggested that EOD-Heating was effective genes under long-day conditions with light-emitting diodes. as a technique for promoting flower bud differen- Planta, 234: 321–330. tiation of many cut flower species. However, little is Islam M.D., Tarkowska D., Clarke J.L., Blystad D.R., Gislerød known about the effect on stem elongation by this H.R., Torre S., Olsen J.E. (2014): Impact of end-of-day red treatment in cut flowers. In this study, 4 long-day and far-red light on plant morphology and hormone physiol- cultivars and 3 day-neutral or short-day cultivars ogy in poinsettia. Scientia Horticulturae, 174: 77–86. showed enhanced stem length by EOD-heating Kasperbauer M.J. (1971): Spectral distribution of light in to- treatment, respectively. Additionally, a significant- bacco canopy & effects of end-of-daylight quality on growth ly higher value of mean internode length in EOD- and development. Plant Physiology, 47: 775–778. heating treatment was shown in only 2 among Kasperbauer M.J., Peaslee D.E. (1973): Morphology and photosyn- these cultivars. Therefore, it is presumed that the thetic efficiency of tobacco leaves that received end-of-day red and effect on internode elongation by EOD-Heating far red light during development. Plant Physiology, 52: 440–442.

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