著者

Tomohiro Kondo Hirokazu Higuchi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-093, (Released:2023-10-11)

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Passion fruit has edible arils with a complicated structure. Each aril has three different membranes; an external membrane, an internal membrane with a fimbriate structure at the basal area, and a transparent membrane that completely envelops the seed. It was reported that juice quality, including organic acid and sugar contents, varied depending on the extraction method. So, organic acid and sugar are potentially localized inside the aril. In this study, using three cultivars (purple passion fruit, yellow passion fruit, and ‘Summer Queen’, a hybrid variety between the two), juice qualities of different aril parts were determined. The aril was separated into three parts, that is, the outer pulp (OP), the distal part of the inner pulp (DIP), and the basal part of the inner pulp (BIP). The OP included the external membrane and the juice held by this membrane. The DIP surrounding the seed and the BIP was a fimbriate structure attached to the internal membrane. In all varieties, titratable acidity (TA) and citric acid content at DIP were higher than those at OP and BIP, although there were some differences among the varieties. Malic acid content did not vary among the parts. Total soluble solid content (TSS) at BIP was the highest among the parts, and glucose, sucrose, and fructose contents at DIP were lower than those at BIP. Purple passion fruit had a high juice content at OP and the yellow cultivar had high juice content at DIP, while the hybrid between the two showed intermediate characteristics. Organic acid and sugar were localized inside the aril in the passion fruit cultivars; the citric acid content and TA at DIP were higher than those at OP and BIP, and TSS at BIP was higher than those at DIP and OP. Therefore, adjusting the juice extraction intensity may be needed depending on the required juice quality.

著者

Hiroshi Matsuda Hirokazu Higuchi Naoki Miyaji Masanori Okabe

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-057, (Released:2023-06-10)

被引用文献数

1

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The salak fruit (snake fruit) contains one to three seeds covered with an aril. The size of the fruit primarily depends on the number of seeds. Fruits with more seeds grow larger and attain higher commercial value in fresh markets owing to their superior appearance. In eastern Thailand, during the hot period in the early rainy season, the fruit set of salak decreases, which is empirically believed to be caused by high night temperatures. In this study, we pollinated and incubated salak spadices at various temperatures (18–36°C) to determine the optimal post-pollination temperature range needed to produce valuable fruits. Chronological pollen-tube elongation in the pistil and development of the early embryo and endosperm were then observed anatomically, followed by fruit-set estimation. At ≤ 21°C, pollen-tube elongation was limited. At 24–27°C, although elongation was slow, pollen tubes attained embryo sacs in > 60% of florets within 36 h after pollination. Pollen tubes elongated fastest at 30–33°C and attained embryo sacs within 12 h after pollination. At 36°C, the difference in the elongation speed tended to be higher among the pistils. The percentages of ovules with developing embryos were the highest at 27°C at 48 h after pollination; zygote and early embryos were observed in 10.8% and 55.9% of the ovules, respectively, and the primary endosperm nucleus, dispersing endosperm nucleoplasm, and free endosperm nuclei were observed in 8.6%, 38.7%, and 19.4%, respectively. The second highest percentage was observed at 24°C. The percentages tended to decrease at 30°C and decreased significantly at ≥ 33°C. At ≥ 30°C, shriveled embryo sacs were observed. The estimated fruit-set percentage based on embryo development as the consequent fruit set was the highest (≈80%) at 27°C, while the second highest percentage (≈75%) was at 24°C. At ≥ 30°C, the estimated percentage decreased to less than half that at 27°C. Fruits containing three seeds were expected to grow in the range of 17.6–28.0% at ≤ 27°C. One- or two-seeded fruits were expected to grow at ≥ 30°C. Limited fruit set was expected at 36°C. Our results indicate that salak prefers relatively cool temperatures of approximately 25°C for the fertilization and set of valuable fruits.

著者

Shota Niwayama Hirokazu Higuchi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-169, (Released:2018-10-26)

被引用文献数

7

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The suitable soil pH for passion fruit growth has been well studied; however, the optimal soil pH for producing high-quality fruit has not been determined. In this study, the effects of soil acidity on fruit quality were determined. One-year-old passion fruit plants were grown in pots filled with soil adjusted to four pH levels (pH 3.5, 4.5, 5.5, and 6.5). The numbers of flowers and fruits were counted, and the external appearance and juice quality of the harvested fruits was evaluated. Vegetative growth, physiological responses, and leaf mineral contents were also measured. At pH 4.5 and 5.5, fruit were heavier and larger, with a better peel color than the fruit at pH 3.5 and 6.5. As indicators of taste, the titratable acid content was lower and total soluble solid content was higher at pH 4.5 and 5.5, indicating preferable palatability. The sugar/acid ratio was highest at pH 4.5. The numbers of flowers and fruits, vegetative growth, and photosynthetic rate were also higher at pH 4.5 and 5.5. Conversely, soil with a near-neutral pH of 6.5 yielded fruit with a pale peel color, severe peel wrinkles, and a low sugar/acid ratio. Vegetative growth was inhibited, and the photosynthetic rate and leaf water potential were lowest at pH 6.5. The leaf/fruit ratio was lower at pH 6.5. A shortage of photosynthate may have reduced fruit quality. Leaf nitrogen, manganese, and zinc contents, as well as the chlorophyll content (SPAD index), were lowest at pH 6.5. Deficiencies in these minerals may have led to a low photosynthetic rate and SPAD index under the higher pH condition. With excessive acidic soil (pH 3.5), vegetative growth, photosynthetic rate, and the number of flowers were as high as those at pH 4.5, although the fruit-set percentage and fruit quality were lower. Thus, strongly acidic soil around pH 4.5 is recommended for producing high-quality passion fruit.

著者

Hiroshi MATSUDA Hirokazu HIGUCHI

出版者

Japanese Society for Tropical Agriculture

雑誌

Tropical Agriculture and Development (ISSN:18828450)

巻号頁・発行日

vol.63, no.2, pp.79-82, 2019 (Released:2020-03-07)

参考文献数

10