著者

Yuka Suehiro Keisuke Mochida Mitsuru Tsuma Yuji Yasuda Hiroyuki Itamura Tomoya Esumi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-046, (Released:2018-12-29)

被引用文献数

12

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Phytohormones play major roles in the berry maturation process. Gibberellic acid (GA) and cytokinin (CK) are phytohormones used in seedless table grape production. Several studies have been conducted on the effects of GA and CK application on berry development. However, the detailed mechanisms underlying their physiological effects on berry maturation after the veraison stage have not been clarified. Skin browning during maturation is a major commercial problem in yellow-green skinned grape cultivars including ‘Shine Muscat’, and expanding our knowledge of these mechanisms is a necessary step towards addressing this problem. In this study, we investigated the effects of GA and CK treatments from the veraison stage to the subsequent developmental stages of this grape berry. Both treatments resulted in enlarged berries and the suppression of increases in sugar content. Chlorophyll in the berry skin was less decomposed after GA/CK treatment, and the occurrence of skin browning in the maturation stage was reduced, as expression of the VvPP2Cs gene decreased. GA/CK treatment at the veraison stage (45–50 DAFB) reduced the expression levels of phytohormone-related genes, particularly those of VvGID1 and VvCHKs, which are involved in GA and CK signaling, respectively. These similar changes in gene expression patterns suggest phytohormonal crosstalk and a common expressional regulatory mechanism. VvACO2 and VvYUC1 expressions were significantly increased in skin browning samples, regardless of treatment, indicating involvement of the ethylene and auxin biosynthesis pathways in skin browning. Therefore, GA/CK treatment at the veraison stage may broadly affect phytohormone biosynthesis and signaling pathways in subsequent developmental stages, although the effect size greatly differs depending on the experimental conditions, including year and plant.

著者

Yuka Suehiro Keisuke Mochida Mitsuru Tsuma Yuji Yasuda Hiroyuki Itamura Tomoya Esumi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-045, (Released:2018-12-29)

被引用文献数

6

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Abscisic acid (ABA) and ethylene are well-known phytohormones that are involved in the maturation of grape berries and other fruits. However, the process of yellow-green skinned grape berry maturation is not well understood due to difficulties in determining grape maturity from changes in skin color. Skin browning during maturation is a major commercial problem in some yellow-green skinned grape cultivars including ‘Shine Muscat’. To resolve this issue, a better understanding of the mechanisms involved in grape maturation and skin-browning is needed. We treated ‘Shine Muscat’ grape clusters at the veraison stage (45–50 DAFB) with spray applications of ABA or ethephon. These treatments produced darker colors and increased the trans-resveratrol and flavonol contents of berry skins. The ABA and ethephon treatments significantly increased the severity of skin browning. Changes in the expression of genes involved in polyphenol biosynthesis and oxidation were consistent with increases in polyphenols and the severity of browning in berry skins. The expression of VvACO2 and VvYUC1 genes, which are involved in ethylene and auxin biosynthesis, respectively, were upregulated in berries with brown skins. Although ABA treatment also increased the size of the berries, the effect of ethephon treatment on berry maturation was similar to, or greater than, that of ABA treatment. In berry skins, the expression of VvACO3, which is involved in phytohormone biosynthesis, increased significantly in response to ABA treatment. Overall, the changes in gene expression produced by ABA and ethephon treatments differed. Therefore, different mechanisms may regulate the physiological responses to ABA and ethephon, although both treatments accelerate berry maturation.

著者

Kazuya Ohata Yasuyuki Togano Toshikazu Matsumoto Yoshinori Uchida Takao Kurahashi Hiroyuki Itamura

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.OKD-044, (Released:2017-01-31)

被引用文献数

4

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Prune trees (Prunus domestica L.) are optimally suited to dry climates, and a major production area for prune trees is California, which has little rainfall. The East Asian temperate monsoon zone, where summer is hot and rainfall is relatively abundant, is not well suited for cultivating prune trees. The purpose of this study was to investigate prune cultivars that are ideal for this temperate monsoon zone to expand the possibility of production. We evaluated the performance of 8 prune cultivars, ‘Puchull’, ‘Purple Ais’, ‘Blue Tan’, ‘Edwards’, ‘Stanley’, ‘Valor’, ‘President’, and ‘Marjorie’s Seedling’, by harvesting fruits from August to October to identify optimal cultivars in Izumo, western Japan, as a model area in the temperate climate monsoon zone. Results showed that the flowering period of prune trees was from late March to mid-April, and average temperature in March influenced whether flowering time would occur early or late. The flowering period varied by year. Therefore, companion planting with other cultivars that have overlapping flowering periods is necessary for self-incompatible cultivars. To avoid spring frost damage during the flowering period, protection from frost was necessary. Additionally, to avoid fruit cracking, cultivating prune trees under rain shelter conditions was also necessary. With these management approaches, two mid-ripening types, ‘Stanley’ and ‘Valor’, and two late-ripening types, ‘President’ and ‘Marjorie’s Seedling’, yielded over 1000 kg/10 a/canopy area and produced high-quality fruit with over 20 soluble solids content (SSC)/titratable acid (TA). However, three early-ripening types, ‘Puchull’, ‘Purple Ais’, and ‘Blue Tan’, and the mid-ripening ‘Edwards’, showed relatively low yields and produced fruit with low SSC/TA. Moreover, flesh darkening before harvest was observed as a result of high-temperature injury in these cultivars, and skin color and fruit taste were not good enough before flesh darkening; thus, these four cultivars were not suitable for table use. In summary, we consider mid- to late-ripening cultivars suitable for table use in Izumo. Our findings also indicate the possibility that these prune fruit cultivation methods could be used in other parts of the East Asian temperate monsoon and humid temperate climate zone.

著者

Mari Sugiyama Takuya Katsube Akio Koyama Hiroyuki Itamura

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.OKD-053, (Released:2017-01-19)

被引用文献数

9

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The aim of this study was to determine the best time to harvest mulberry (Morus alba L.) leaves for optimal yields of functional components. Mulberry leaves were analyzed to determine the seasonal changes in the concentrations of functional components, including flavonols, chlorogenic acid, and 1-deoxynojirimycine (DNJ). During the experimental period (May 26–October 16), the ranges of flavonols, chlorogenic acid, and DNJ contents were 1134–2230 mg/100 g dry weight (DW), 616–1014 mg/100 g DW, and 53–199 mg/100 g DW, respectively. There were high flavonols contents in mulberry leaves from late May to early July, from early to mid-August, and after late September. There were high chlorogenic acid contents from late May to early July, and after late September. From late September, the flavonols contents increased over time, and showed the highest level on October 16, the last day of the experimental period. The increased flavonols contents after late September were due to the synergistic effects of solar radiation and lower temperatures. The DNJ content showed a bell-shaped curve, peaking in mid-August, and the DNJ content was strongly correlated with total temperature. The flavonols and chlorogenic acid contents in mulberry leaves were higher after late September when the temperatures decreased and there was still high solar radiation, while the DNJ content peaked in August when temperatures were highest. The results indicated that August is the best time to harvest mulberry leaves to obtain optimal yields of beneficial functional components. If mulberry leaves are harvested twice per year, then the first harvest should be in July to August when temperatures and solar radiation hours are high, and the second harvest should be completed by the end of September.