著者

Yoshikuni Kitamura Tatsuya Uemachi Yukari Kato

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-160, (Released:2016-09-15)

被引用文献数

2

---

We compared transpirations and vase lives of cut hydrangea (Hydrangea spp.) flowers using two cultivars with lacecap inflorescence (‘Blue sky’ and ‘S-1’) and their mutants with hortensia inflorescence (‘BM-1’ and ‘SM-1’). There was no significant difference in the transpirations from cut flowers with the lacecap and hortensia inflorescences in the two cultivars. However, transpiration from ‘S-1’ cut flowers tended to exhibit higher transpiration than ‘SM-1’. There was also no significant difference in the vase lives of ‘Blue sky’ and ‘BM-1’. However, ‘S-1’ had a significantly shorter vase life (3 days) than its mutant ‘SM-1’. This was due to the greater number of total florets in ‘S-1’ cut flowers than ‘SM-1’. The non-decorative floret clusters and clusters of petals, stamens, and pistil of decorative florets exhibited lower temperatures than decorative sepals in both ‘Blue sky’ and ‘BM-1’ on thermal images. Therefore, we estimated the transpiration from the non-decorative florets and studied the effect of removal of non-decorative florets on the vase life of cut flowers using two lacecap cultivars, ‘Blue sky’ and ‘Fairy eye’. Estimated transpirations from the non-decorative florets of ‘Blue sky’ and ‘Fairy eye’ accounted for approximately 61.8% and 39.7%, respectively, of total transpirations per cut flower, and the removal of non-decorative florets significantly extended the vase lives of cut flowers (18 and 22 days, respectively). The difference in the contribution of the non-decorative florets to the transpiration between the cultivars is due to the difference in the number of non-decorative florets in the inflorescences. We conclude that the use of cut flowers that do not bear too many non-decorative florets and/or treatments that suppress the transpiration from non-decorative florets would be effective in extending the vase life of cut hydrangea flowers with lacecap inflorescence.

著者

Yoshikuni Kitamura Takafumi Watanabe Yukari Kato WeiWei Teoh Keiko Kataoka Yuki Yamaguchi Tomohiro Haruta Hideo Nishioka Kiyokazu Kametani

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-003, (Released:2018-06-19)

被引用文献数

1

---

Information about mechanical reinforcement of decorative organs could help development of a novel technique that would give flowers with robust floral organs and broadly contribute to postharvest flower preservation. Hydrangeas (Hydrangea spp.) exhibit remarkable characteristics in terms of mechanical reinforcement of decorative sepals. Although decorative sepals at the flowering stage shrink when they are desiccated, decorative sepals after flowering maintain their shape even after desiccation. In this study, the lignifications of the vein cells in decorative sepals were analyzed using phloroglucinol/HCl-staining. The microstructure of the cell wall was analyzed using transmission electron microscopy (TEM). The three-dimensional structure of vein cells was analyzed using serial block-face scanning electron microscopy (SBF-SEM). Tubular- and spindle-shaped dead cells with a lignified pitted secondary cell wall were observed around the vessel elements in decorative sepals after flowering. These cells were observed as living cells without a secondary cell wall in the veins of decorative sepals at flowering and in fully expanded leaves. Further, 10 hydrangea cultivars were analyzed for development of mechanical reinforcement in vein cells, and some of them were compared by desiccation testing. Decorative sepals of a cultivar lacking those cells exhibited shrinkage after flowering when they were desiccated. In conclusion, dead cells with a lignified pitted secondary cell wall contribute to the reinforcement of veins in decorative sepals of hydrangeas and become sclerified parenchyma cells. Axial parenchyma sclerifying in veins after flowering is essential for robust hydrangea floral organs and represent a new type of mechanical reinforcement tissue in plant decorative floral organs.

著者

Yoshikuni Kitamura Tetsuya Hattori Kaori Mogami Takashi Fudano Mariko Uehara

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-152, (Released:2018-04-25)

被引用文献数

2

---

Hydrangea (Hydrangea spp.) flower buds usually differentiate from the end of summer through autumn, but some cultivars can also produce flower buds in spring. In the present study, we selected cultivars with high potential for such unseasonable flower bud production in Japan by evaluating the flower bud production on pinch-treatment-induced axillary shoots. We also examined the pinching time and the difference between the two shoot types: previously formed shoots that developed from buds formed in the previous autumn and basal shoots that formed in the current spring. We found that ‘Christmas’, ‘Endless Summer’, and ‘Rosea’ had the highest frequencies of unseasonable flower bud production on the axillary shoots of previously formed shoots (90.0%, 80.0%, and 90.0%, respectively) and basal shoots (90.0% for all three cultivars). When the buds were pinched in mid-April, the axillary shoots that formed on both shoot types flowered from early July to mid-August, which was approximately 1 month later than for seasonably produced flower buds in the same cultivars. In 2011, 98.0%, 90.5%, and 84.0% of the axillary shoots that developed on previously formed shoots flowered in ‘Christmas’, ‘Endless Summer’, and ‘Rosea’, respectively, while in 2012, 63.2%, 54.9%, and 75.3% flowered, respectively. Similar values were seen for the basal shoots, with the exception of ‘Christmas’ in 2011 and ‘Endless Summer’ in 2012, which both had lower flowering rates than previously formed shoots. In ‘Rosea’, flower bud differentiation started just after the pinch treatment, and the frequency of flower bud production decreased when the pinch treatment was conducted after late April. Thus, ‘Christmas’, ‘Endless Summer’, and ‘Rosea’ were considered to have high potential for unseasonable flowering following pinch treatment in early spring. However, unseasonable flower bud production may often be suppressed in pinched basal shoots.

著者

Yoshikuni Kitamura Sachiyo Ueno Hiroe Aizawa WeiWei Teoh

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-111, (Released:2017-12-20)

被引用文献数

5

---

Two types of cut hydrangea flowers are marketed: Fresh-stage cut flowers (harvested just after the decorative sepals are completely colored before or during flowering) and antique-stage cut flowers (harvested when the decorative sepals become green and/or red after flowering). We investigated the differences in vase lives between fresh- and antique-stage cut flowers using 10 cultivars and 5 lines of hydrangea. The antique-stage cut flowers of ‘Endless Summer’, ‘Glowing Alps’, ‘Grünherz’, ‘Masja’, ‘Temari Ezo’, and line No. 2 exhibited significantly longer vase lives than their fresh-stage cut flowers. The difference in vase lives between the cut flowers of ‘Masja’ harvested at two different stages was approximately 60 days. We conducted further studies to elucidate the contribution of detailed differences in the harvest stages to differences in the vase lives using ‘Masja’ and ‘Xi’an’. Vase lives were compared among the cut flowers harvested at four different harvest stages that were divided based on flowering of florets and greening of the decorative sepals. The cut flowers of ‘Xi’an’ harvested at the decorative florets flowering- and decorative sepal greening-stages showed significantly longer vase lives than those harvested at the non-decorative floret flowering stage. The cut flowers of ‘Masja’ harvested at two harvest stages following the beginning of the decorative sepal greening stage exhibited significantly longer vase lives than those harvested at the other two harvest stages. A recutting treatment rescued the cut flowers harvested at the decorative sepal greening completed-stages that exhibited softening of the decorative sepals. This result suggested that the vase lives of cut hydrangea flowers were terminated by the disruption of water balance caused by vessel occlusion in the stem ends. In conclusion, a relatively longer vase life can be expected when cut hydrangea flowers are harvested after flowering of the decorative florets. However, we should note that cut flowers of some cultivars harvested at the decorative floret flowering stage may exhibit relatively short vase lives. Treatments that suppress vessel occlusion may be effective for lengthening the vase lives of cut hydrangea flowers.

著者

Yoshikuni Kitamura Yukari Kato Toshiki Yasui Hiroe Aizawa Sachiyo Ueno

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-128, (Released:2016-06-08)

被引用文献数

6

---

Cut hydrangea (Hydrangea spp.) flowers are marketed at two different harvest stages, the fresh- and antique-stages. Flowers cut at the fresh-stage are harvested just after the coloring of decorative sepals is completed before flowering, and flowers cut at the antique-stage are harvested when the decorative sepals develop green and/or red colors after flowering. In almost all cultivars, an increase in the hydraulic conductance of the stomata (stomatal conductance) of the abaxial side of decorative sepals occurs during the transition from the fresh to the antique-stage. We investigated the relation between the stomatal conductance increase and the severity of the damage to decorative sepals. The degree of stomatal conductance increase regressed with the severity of the damage occurrence to the antique-stage decorative sepals before harvest. The relation between the stomatal conductance increase and vase life of antique-stage cut hydrangea flowers was also investigated. Abscisic acid (ABA)-treated antique-stage cut flowers exhibited lower stomatal conductance on the abaxial side of decorative sepals than control cut flowers. A photoperiodic change in the transpiration was observed in the control cut flowers, but not in ABA-treated cut flowers. These ABA treated cut flowers had longer vase lives than control cut flowers. To achieve minimal damage before harvest and longer vase life in the antique-stage during cut hydrangea flower production, screening for stomatal conductance non-increasing cultivars would be desirable. Since the stomatal conductance of antique-stage decorative sepals showed a highly significant correlation with fresh-stage decorative sepals, these can be used as an index in screening for stomatal conductance non-increasing cultivars.