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Quality Improvement of Ornamental Flowers

Special Issue:
Quality Improvement of Ornamental Flowers

Editor: Kunio Yamada, Masayoshi Nakayama, and Kazuo Ichimura
April 2024

The Japanese Society for Horticultural Science has published special issues of The Horticulture Journal (Hort. J.) to further enhance the value and attractiveness of this journal. The theme of the sixth special issue is “Quality Improvement of Ornamental Flowers”.

Ornamental flowers play a significant role in our lives, beautifying gardens, homes, and public areas with their pleasing appearance and fragrance. However, achieving excellence quality in ornamental flowers involves overcoming various challenges, ranging from genetic diversity and environmental factors to post-harvest handling and consumer preferences. The quality of ornamental flowers varies widely, encompassing traits like appearance, color, fragrance, and ornamental period such as vase life in postharvest conditions, which are important factors in increasing their value.

This special issue covers a range of topics to improve the quality of ornamental flowers, including breeding of new varieties with novel traits, innovative production system in protected horticulture, post-harvest techniques for maintaining the quality of cut flowers during storage, and efficient transportation systems for quality control. Additionally, the issue explores aspects of plant physiology, molecular biology, and biotechnology for enhancing quality. Furthermore, this issue emphasizes the multidisciplinary nature of horticulture, drawing insights from genetics, physiology, chemistry, and related fields. By promoting collaboration, we aim to address these challenges and contribute to the advancement of ornamental horticultural sciences and the floral industry as a whole.

We hope that this special issue inspires further research and innovation in enhancing the quality of ornamental flowers.


Katsuhiko Inamoto, Tanjuro Goto, Motoaki Doi

Pages: 93 (2): 101–113. 2024.|doi: 10.2503/hortj.QH-102


Three rose varieties, ‘Meivildo’, ‘Meikatana’, and ‘Korcut0122’ were grown using an “arching” method for three years. The relationship between temperature and light intensity, and the yield and quality of cut flowers, were analyzed. Flowering flushes were observed 18 times in ‘Meivildo’ and ‘Meikatana’ and 16 times in ‘Korcut0122’ during the experimental period. In three varieties, significant negative linear regressions between the interval of flowering flush (growth period, GP) and the mean temperature per GP were observed. Significant positive correlations and linear regression were observed between the number of cut flowers per plant and the mean temperature in ‘Meivildo’ and ‘Meikatana’, and the total light integral per GP (TLI) in ‘Korcut0122’. In three varieties, significant positive correlations and linear regressions were observed between the total cut flower weight per plant, and the mean daily light integral per GP (DLI) and TLI. Highly significant positive correlations and linear regressions were observed between the daily gain in flower weight (DGW) of cut flowers per plant (the total cut flower weight divided by the number of days of GP) and the mean DLI in all three varieties. In ‘Meivildo’ and ‘Meikatana’, cut flower weight per stem had significant negative correlations and linear regression with mean temperature and positive ones with TLI, while ‘Korcut0122’ showed no significant correlation with the three environmental factors. Significant positive correlations and linear regressions existed between the specific cut flower weight (the cut flower weight per stem length) and TLI in all three varieties, and negative ones existed between the specific cut flower weight and mean temperature in ‘Meivildo’ and ‘Meikatana’. The relationship between the results in this experiment and previous reports on the relation between the environment and cut flower yield quality are discussed. Finally, we present the significance of the method used in this experiment for 1) prediction of flowering and shipping of cut flowers, 2) evaluation of differences in characteristics among the rose varieties, and 3) contribution to the development of a growth model.

Qi Qin, Fumi Tatsuzawa, Takahisa Nakane, Takashi Kaidzuka, Tsukasa Iwashina, Takayuki Mizuno

Pages: 93 (2): 114–125. 2024.|doi: 10.2503/hortj.QH-098


Isolation, purification and identification of anthocyanins and flavonols were carried out on flowers of Ranunculus cultivars. Three anthocyanins and 11 flavonols were characterized by chemical and spectroscopic techniques. The anthocyanins were identified as cyanidin 3-O-sambubioside, cyanidin 3-O-(6''-malonylsambubioside) and delphinidin 3-O-(6''-malonylsambubioside). The flavonols were identified as 3-O-glucosides and 3-O-sophorosides of kaempferol and quercetin, and their acylated compounds with malonic acid. Flower colors were divided into six groups, Red-Purple, White, Yellow-Orange, Orange, Red, and Violet groups using the Royal Horticultural Society Colour Chart. The absorption maxima of buffer solutions containing anthocyanins and flavonols isolated in this study were measured to understand the effect of intermolecular copigmentation between these compounds on flower color. The results showed that by addition of 3-O-(6''-malonylglucoside) of kaempferol or quercetin, the absorption maximum of cyanidin 3-O-(6''-malonylsambubioside) or delphinidin 3-O-(6''-malonylsambubioside) shifted bathochromically and exhibited a closer absorption maximum to fresh flower petals than anthocyanin alone. This indicates that the intermolecular copigment effect between anthocyanins and flavonols is responsible for the flower color expression in Ranunculus cultivars.

Makoto Tonooka, Akari Iriya, Kazuo Ichimura

Pages: 93 (2): 126–134. 2024.|doi: 10.2503/hortj.QH-109


Treatment with calcium chloride (CaCl2) is known to suppress the occurrence of flower stem bending and extend the vase life of cut gerbera. To clarify whether vase life extension by CaCl2 is improved by combined treatment with gibberellin A3 (GA3), the effect of treatment with 50 mg·L−1 GA3, 5 g·L−1 CaCl2 or in combination on the vase life of the cut gerbera ʻMinouʼ was investigated. To inhibit bacterial proliferation, which is known to shorten vase life, an isothiazoline antimicrobial compound was included in the vase solution. Treatment with GA3 alone delayed the opening of tubular florets and increased the area of unopen florets, but stem elongation which led to stem bending shortened vase life. Treatment with GA3 in combination with CaCl2 suppressed the occurrence of stem bending. Combined treatment with GA3 and CaCl2 extended the vase life of cut gerbera more than treatment with CaCl2 alone. To clarify whether GA3 delays petal senescence, the effect of GA3 at 10 and 50 mg·L−1 on petal senescence was investigated using shortened stems. GA3 at both concentrations significantly delayed petal senescence. Combined treatment with GA3 and CaCl2 also significantly extended the vase life of the cut gerbera ʻKimseyʼ and ʻSandyʼ. It was concluded that combined treatment with GA3 and CaCl2 is a suitable treatment for extending the vase life of cut gerbera.

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