diagnosis before fruit maturation in fruit crops. Longan ( Dimocarpus longan Lour.), a widely cultivated Sapindaceae fruit in the tropics, is highly appreciated for its succulent, sweet, and unique taste and health-related nutrients ( Wall, 2006 ). In
Han Xu, Cuihua Bai, Wei Wang, Changmin Zhou, Luwei Zhu, and Lixian Yao
Marisa M. Wall, Kate A. Nishijima, Lisa M. Keith, and Mike A. Nagao
Longan ( Dimocarpus longan Lour.) is a subtropical fruit of the Sapindaceae originating from Burma to southern China ( Nakasone and Paull, 1998 ; Tongdee, 1997 ). The fruit has a thin, light brown rind surrounding a sweet, white aril with a black
Tracie K. Matsumoto, Mike A. Nagao, and Bruce Mackey
Longan is in the Sapindaceae family along with its other better known relatives, lychee ( Litchi chinensis ) and rambutan ( Nephelium lappaceum ). Commonly referred to as dragon eye, the longan fruit is smooth, round, and yellowish brown at harvest
Yu-Xiong Zhong, Jian-Ye Chen, Hai-Ling Feng, Jian-Fei Kuang, Ruo Xiao, Min Ou, Hui Xie, Wang-Jin Lu, Yue-Ming Jiang, and He-Tong Lin
Longan is a nonclimacteric subtropical fruit with high value ( Huang, 1995 ; Paull and Chen, 1987 ). The edible portion of longan fruit is a fleshy and translucent white aril. However, the fruit deteriorate rapidly after harvest, due to pericarp
Saquib Waheed, Yuan Peng, and Lihui Zeng
Dimocarpus longan (longan) is an evergreen fruit tree that belongs to the Sapindaceae family and grows well in many tropical and subtropical regions of the world. China is top-ranked in terms of the plantation area and fruit production of longan
Chung-Ruey Yen and Jer-Way Chang
Fruit growth curves of three longan varieties showed single sigmoid. Seed was the major sink in longan at early fruit development. Aril grew only after seed had approached full development. Early `Yangtaoyeh' grew more rapidly than two later varieties. Desweeting, levels of aril total soluble solids (TSS) increased to maximum and then declined gradually at later fruit development, occurs often in longan. Variation of desweeting rate among varieties was significant. Increases of fruit weight during desweeting (from dates of maximum TSS to end of experiment) were 55.4%, 50.9%, and 7.3% for `Yangtaoyeh', `Fenko', and `Shihyueh', respectively. Periods of water contents increase in aril coincided with the changes of fruit weight of three varieties. Dilution of TSS by water inflow was one of major factor of desweeting in longan fruit. Girdling did not slow down decline of aril total soluble solids.
Miki Nakata, Nobuo Sugiyama, and Tanachai Pankasemsuk
The structure and developmental patterns of inflorescence of longan (Dimocarpus longan Lour.) were studied microscopically and by the naked eye. In inflorescence of longan, compound dichasia are arranged on three to four orders of monopodial axes without the formation of terminal flowers, indicating that longan inflorescence is pleiothyrse; cymose partial inflorescences are arranged on more than two monopodial axes. Most of the monopodial axes had differentiated by the end of November just before the cool season. The first sign of inflorescence formation was the appearance of bract primordia at apical meristems of the preformed monopodial axes, with lateral axes preceding the main axes. Dichasia were formed in the axils of bract primordia, and the formation of bracts and dichasia continued. Bract appearance can be detected by the naked eye 1 week after microscopically detected bract appearance. Shoots with intermediate characteristics between the inflorescence and the vegetative shoots were formed; dichasia were formed on the lateral axes, but not on the main axes in intermediate shoots. These results suggest that apical meristems on the terminal shoot produce monopodial axes, together with foliage leaf primordia, before floral induction, but produce bract primordia and compound dichasia, which are composed of sympodial axes, after floral induction.
Sharon Sowa, Eric E. Roos, and Francis Zee
Seeds of the recalcitrant species lychee (Litchi chinénsis Sonn.) and longan (Dimocarpus longan Lour.) were stored near 100% relative humidity at 8 to 10C in air, 80% nitrous oxide (N2O) plus 20% oxygen, or 100% nitrous oxide. The combination of anesthetic and oxygen extended storage longevity of both species. Seeds stored in 100% N2O lost terminability at the same rate as those stored in air. Lychee seeds retained 92% of initial germination after 12 weeks under 80% N2O/20% O2, while those under air retained only 44%. Longan seeds failed to germinate after 7 weeks under air, yet retained 70% of their initial germination under 809” N2O/20% O2. The combination of anesthetic and oxygen atmospheres could provide a new approach to recalcitrant seed storage.
Sharon Sowa, Eric E. Roos, and Francis Zee
Seeds of the recalcitrant species Litch i chinénis and Euphoria longan were stored in humid conditions at 8-10C under three different atmospheres: air, 80% nitrous oxide (N20)/20 % oxygen, and 100% nitrous oxide. The combination of anesthetic and oxygen extended storage longevity of both species. Oxygen was required for maintenance of viability; seeds stored under 100% N20 lost germinability at the most rapid rate. Lychee seeds retained 92% of control germination after 12 weeks under 80% N20/20% 02, while those under air lost 56% viability. Longan seeds lost all viability after 7 weeks under air, yet retained 70% of their control germination under 80% N20/20% 02. The combination of anesthetic and oxygen atmospheres could provide a new approach to recalcitrant seed storage.
Peter A. Follett and Suzanne S. Sanxter
Hot-water immersion and irradiation quarantine treatments are used to disinfest longan [Dimocarpus longan (Lour.) Steud.] of fruit flies and other pests before export from Hawaii to the U.S. mainland. One day after harvest, longan fruit (cvs. Chompoo and Biew Kiew) were subjected to hot-water immersion at 49 °C for 20 minutes, irradiation treatment at a minimum absorbed dose of 400 Gy, or left untreated as controls. Fruit were then stored at 10 °C in perforated plastic bags, and quality attributes were evaluated after 7, 14, and 21 days. `Chompoo' and `Biew Kiew' fruit treated by hot-water immersion were darker (lower L*) and less intensely colored (lower C*) than irradiated or untreated fruits after 14 days of posttreatment storage. For both cultivars, external appearance of fruit treated by hot-water immersion was rated as unacceptable after 14 and 21 days of posttreatment storage, whereas irradiated and nontreated fruit were rated as acceptable on all days. Penicillium mold contributed to the unacceptable external appearance ratings after 21 days for fruit that were treated by hot-water immersion. With both cultivars, taste of fruit treated with hot-water immersion was rated as unacceptable after 21 days of storage, whereas irradiated fruit remained acceptable. Overall, under these experimental conditions, irradiation was superior to hot-water immersion as a quarantine treatment based upon the maintenance of fruit quality.