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Rasika G. Mudalige-Jayawickrama, Michele M. Champagne, A. David Hieber, and Adelheid R. Kuehnle

Two full-length cDNA clones, Den-CHS-4 and Den-DFR-1, encoding chalcone synthase (CHS) and dihydroflavonol 4-reductase (DFR) were obtained from flower bud RNA of a lavender cyanidin-accumulating Dendrobium Sw. hybrid using reverse transcription-polymerase chain reaction (RT-PCR). Northern analyses indicated that both genes are expressed in all developmental stages of buds, with highest expression in the medium-sized buds. RT-PCR analyses showed that DFR expression was confined to floral tissue while CHS was expressed in floral and vegetative tissues but not in pseudobulbs. The nucleotide sequence of a DFR clone isolated from a pale orange pelargonidin-accumulating Dendrobium hybrid was exactly the same as Den-DFR-1, ruling out the substrate specificity of DFR as a possible cause of the color difference.

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Conway LI. Powell, Kate I. Caldwell, Ray A. Littler, and Ian Warrington

Abstract

Clonally produced plants of Cymbidium Astronaut ‘Rajah’ (3.5 years exflask) were assigned to three day/night temperature regimes (20°C day/12° night, 26°/12°, and 26°/18°) at two nitrogen fertilizer rates (17 and 170 ppm N in the daily nutrient feed) in controlled environment rooms in Oct. 1984. Plants were removed at seven regular intervals between 29 Oct. 1984 and 15 Apr. 1985 and destructively harvested for assessment of bud development. There were, on average, 4.4 renewal vegetative buds (≥25 mm long) per plant produced over the 6-month experimental period with no apparent effect of temperature or nitrogen treatments on this cultivar. Of all vegetative renewal buds, 73% occurred on the bottom two nodes of the pseudobulb, whereas only 36% of reproductive buds grew from the bottom two nodes. Reproductive buds occurred up to the eighth node. By harvest 7, the 26°/12° temperature regime resulted in 5.9 reproductive buds per plant, with only 0.8 and 1.7 reproductive buds per plant, respectively, observed for the 20°/12° and 26°/18° temperature treatments. There was no effect of nitrogen fertilizer on floral bud numbers.

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Boris Andrés Bran Barrientos and Jong-Yi Fang

With the increased popularity of orchids, a need exists for the introduction of new commercially valuable species to uphold consumer’s attention. In recent years, commercial production and cultivation of native orchid species have increased

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Cibele Mantovani, Jonas Pereira de Souza Júnior, Renato de Mello Prado, and Kathia Fernandes Lopes Pivetta

via leaf spray, as reported for Stevia rebaudiana ( El-Housini et al., 2014 ) and violets ( Martín-Mex et al., 2005 ). The in vitro cultivation of orchids has expanded, and the inclusion of SA in the growth medium may enhance their growth, but there

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Rebecca C.-C. Hsu and Yung-I Lee

The genus Cypripedium L. is one of the most fascinating groups of orchids, distributing in the temperate region or the high mountains of the Northern Hemisphere ( Cribb, 1997 ). Species of this genus are of high value in ornamental markets because

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Nadia Jiménez-Peña, Luis A. Valdez-Aguilar, Ana M. Castillo-González, María T. Colinas-León, Andrew D. Cartmill, and Donita L. Cartmill

. Laelia anceps Lindl. is an epiphytic orchid that naturally occurs in the oak forests of the central and southern regions of the country. In the fall and winter, L. anceps produce flower stalks bearing white or pink flowers (8 to 10 cm in diameter) of

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Nguyen Phuc Huy, Vu Quoc Luan, Le Kim Cuong, Nguyen Ba Nam, Hoang Thanh Tung, Vu Thi Hien, Dung Tien Le, Kee Yoeup Paek, and Duong Tan Nhut

) to induce stem elongation (Fig. 1b 2 and 2a). Under dark conditions, orchid plants tended to elongate. However, if subjected to dark conditions for a long time, the plant will lose all pigment due to the lack of photosynthesis. Therefore, in this