Phalaenopsis and Doritaenopsis (intergeneric hybrids between Phalaenopsis species and Doritis pulcherrima Lindley and between their hybrids or species) require a relatively warm environment to grow quickly ( Krizek and Lawson, 1974 ; Lee, 1991 ; Lee
Nuclear DNA contents were estimated by flow cytometry in 18 Phalaenopsis Blume species and Doritis pulcherrima Lindl. DNA amounts differed 6.07-fold, from 2.74 pg/diploid nuclear DNA content (2C) in P. sanderiana Rchb.f. to 16.61 pg/2C in P. parishii Rchb.f. Nuclear DNA contents of P. aphrodite Rchb.f. clones, W01-38 (2n = 2x = 38), W01-41 (2n = 3x = 57), and W01-22 (2n = 4x = 76), displayed a linear relationship with their chromosome numbers, indicating the accuracy of flow cytometry. Our results also suggest that the 2C-values of the Phalaenopsis sp. correlate with their chromosome sizes. The comparative analyses of DNA contents may provide information to molecular geneticists and systematists for genome analysis in Phalaenopsis. Endoreduplication was found in various tissues of P. equestris at different levels. The highest degree of endoreduplication in P. equestris was detected in leaves.
Genetic complementation was used to correct the albescent flower color mutation of the orchid Doritis pulcherrima. The Zea mays anthocyanin regulatory genes C 1 and B were introduced into the petal cells via particle bombardment. Anthocyanin pigmentation developed within the bombarded cells after 48 hours. This suggests that the albescent phenotype was the result of a defective regulatory gene(s) and not the result of a defective structural gene(s). Genetic complementation via particle bombardment requires considerably less time than via classical breeding and could be used on other species or with other genes.
It not clear how a prolonged period of cool days and warm nights affect Phalaenopsis hybrids which take up CO2 mainly at night. The `Lava Glow' clone of the hybrid Doritaenopsis (Phal. Buddha's Treasure × Doritis pulcherrima) 15 cm in leaf span were subjected to day/night (12 h each daily) temperatures of 30/25, 25/30, 25/20, or 20/25 °C at 170 umol.m-2 .s-1 PPF. After nine months, plants under the higher average daily temperature (ADT) produced more leaves. Those grown at 30/25 °C had the largest leaf span and total length of the new leaves. Plants under 30/25, 25/30, 25/20, or 20/25 °C had 5.0, 4.7, 3.6, and 2.8 new leaves and 72, 61, 42, and 28 cm in total new leaf length, respectively. Cool days and warm nights resulted in smaller leaf span and reduced leaf growth, particularly at 20/25 than at 25/30 °C. Within a given ADT, cooler days resulted in shorter leaves. Leaves produced by plants at the lower ADT had a smaller length to width ratio and the more desirable oval shape. The most striking effect of 20/25 °C was that 14 out of 15 plants bloomed, whereas only 5 plants under 25/20 °C and none in the 30/25 or 25/30 °C treatment flowered. In a second experiment, 18-22 cm plants were subjected to 30/20, 20/30, 25/15, or 15/25 °C. After 29 weeks, similar results were obtained. All plants under 15/25 °C bloomed, whereas none in the other treatments produced flowers. Long-term exposure to 15/25 °C resulted in slow leaf production and undesirable small leaves. These results suggest that, with day temperatures in the 20-15 °C range, nights 10-5 °C warmer are not desirable for rapid vegetative growth. However, cool days and warm nights may be used to effectively induce the flowering process.
the same chromosome number, but genome sizes vary considerably ( Kao et al., 2001 ). For instance, Shindo and Kamemoto (1963) compared the mean chromosome length of eight Phalaenopsis species and the closely related species Doritis pulcherrima
In vitro germination of some western European orchids Physiol. Plant. 67 253 261 Wu, C.H. Ye, X.L. Liang, C.Y. 2005 In vitro seed germination in Doritis pulcherrima Guihaia 25 2 149 151 Wu, Z.Y. Raven, P.H. Hong, D.Y. 2009 Flora of China Vol. 25
hybrida Vllm J. Hered. 87 241 245 Griesbach, R.J. 1997 Biochemical basis for the blue flower color mutations in Doritis pulcherrima and Phalaenopsis violacea Lindleyana 12 64 71 Griesbach, R.J. 2005 A scientific approach to breeding blue orchids
, R. Klein, T. 1993 In situ genetic complementation of a flower color mutant in Doritis pulcherrima (Orchidaceae) Lindleyana 8 223 226 Grotewold, E. Sainz, M.B. Tagliani, L. Hernandez, J
). Doritaenopsis Guillaum. & Lami is a popular hybrid between Phalaenopsis Blume and Doritis pulcherrima Lindl. and is used as a potted plant or cut flower ( Tsukazaki et al., 2000 ). General micropropagation procedures for Doritaenopsis and Phalaenopsis
/Feb. Thammasiri, K. 2000 Cryopreservation of seeds of a Thai orchid ( Doritis pulcherrima Lindl.) by vitrification Cryo Letters 21 237 244 Towill, L.E. 1985 Low temperature and freeze-/vacuum-drying preservation of pollen