著者

Gang Ma Lancui Zhang Kan Murakami Masaki Yahata Masaya Kato

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-082, (Released:2023-08-11)

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‘Miyagawa-wase’ (Citrus unshiu Marcow.), an early-season citrus variety, is rich in multiple nutrients and widely consumed in Japan. In ‘Miyagawa-wase’, when the pulp reaches maturity and is ready to eat, the peel is still a greenish color because of the relatively high temperature in the harvest season. In this study, to improve the coloration of ‘Miyagawa-wase’ peel, we treated the fruit with 1-naphthaleneacetic acid (NAA) after harvest. The results showed that postharvest treatment with NAA was effective to induce chlorophyll degradation and carotenoid accumulation in ‘Miyagawa-wase’ peel during storage. In the NAA treatment, the reduction in the chlorophyll contents after harvest was in parallel with decreases in the expression of chlorophyll biosynthetic genes (CitGGDR, CitCHLH, CitCHL27, CitPORA, and CitCAO) and an increase in chlorophyll degradation gene CitPPH. The contents of the major carotenoids, β-cryptoxanthin and 9-cis-violaxanthin, were increased by the NAA treatment through upregulation of the expression of carotenoid biosynthetic genes (CitPSY, CitPDS, CitZDS, CitLCYb2, and CitHYb) after harvest. In addition, it was found that the positive effect on degreening in the NAA treatment was inhibited by the ethylene antagonist 1-MCP. In the combination treatment using NAA and 1-MCP, the total chlorophyll content was much higher, while the contents of β-cryptoxanthin and 9-cis-violaxanthin were lower compared with NAA treatment alone, indicating that the acceleration of degreening by NAA may be caused by ethylene. The results presented in this study suggest that postharvest NAA treatment is an effective method for improving the peel coloration in early-season citrus varieties.

著者

Shiro Mori Takuya Yamane Masaki Yahata Koichi Shinoda Naho Murata

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-117, (Released:2016-03-25)

被引用文献数

9

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Limonium bellidifolium (2n = 2x = 18), a perennial statice belonging to the family Plumbaginaceae, is cultivated as a garden plant or for cut flowers and is an important breeding material for the production of hybrid cultivars in the genus. In this study, chromosome doubling in L. bellidifolium was attempted to increase the variability in horticultural traits. Seeds of this species were treated with an antimitotic agent, colchicine, at different concentrations and exposure periods. The treated seeds were sown in soil in a cell tray and the seedlings were grown in a greenhouse. More than 50% of the seedlings treated with colchicine for 24 or 48 h, irrespective of the concentration, survived for 4 months after treatment. Most of the seedlings treated for 72 h at any concentration showed very poor growth and abnormal thickening of the hypocotyl, and ultimately died. The surviving seedlings were grown in 9-cm pots. Flow cytometry analysis of leaf tissues showed that 2.5%–5% of plants that received 0.05% colchicine for 72 h, 0.25% colchicine for 24 h, 0.25% colchicine for 48 h, or 0.5% colchicine for 48 h were tetraploid (4x) or mixoploid (2x + 4x). The highest frequencies of tetraploids and mixoploids occurred following treatment with 0.05% colchicine for 72 h. These results showed that colchicine treatment of seeds is effective for chromosome doubling in L. bellidifolium. After 3 years of cultivation, the morphological characteristics of diploid and tetraploid L. bellidifolium plants at the flowering stage were investigated. The stomatal density was lower in all investigated tetraploid and mixoploid plants than in the control diploid plant. The stomatal length was 1.1- to 1.5-fold higher in all tetraploid and mixoploid plants than in the control. Tetraploid plants tended to have wider and thicker leaves than the control and also produced larger flowers.