Seiichi Fukai, Atsushi Hasegawa, and Masanori Goi
Nuclear DNA content in various parts of Cymbidium plants was measured by flow cytometry. Two types of Cymbidium, protocorm-like body (PLB)-propagated epiphytic hybrids and rhizome-propagated terrestrial C. kanran Makino demonstrated polysomaty. Small shoots on PLBs of Cymbidium hybrids showed two peaks (2C and 4C) while PLBs showed four peaks, estimated to be 2C, 4C, 8C, and 16C. Roots and floral organs excluding ovaries of hybrids were highly polysomatic as were the rhizomes and roots of C. kanran. The patterns of polysomaty development were organ and developmental stage specific. Young leaves taken from in vitro plants are suitable material for determining the ploidy levels of Cymbidium plants by flow cytometry.
Ahmet Esitken, Sezai Ercisli, Cafer Eken, and David Tay
Seeds of Orchis palustris Jacq. were primed for 1- to 5-day in polyethylene glycol (PEG-6000) solutions at -0.5, -1.0 or -1.5 MPa. The seeds were symbiotically germinated with BNR 8-3 mycorrhizal fungus on oatmeal agar at 22 °C. In general, priming hastened rapid germination. At -1.5 MPa water potential, the first to germinate was eight days compared to 18 days for the control. Percentage germination increased as priming water potential decreased, and the percentage germination was 55%, 58%, and 65%, at -0.5, -1.0, and -1.5 MPa, respectively, versus 43% for the nonprimed control. Priming duration from 1 to 5 days had little effect on germination performance. The best germination percentage (68%) was obtained from 1 day at -1.5 MPa treatment.
Dendrobium Linnapa `No. 3' plants were potted one per 1.75-liter pot with large or small fir bark with or without 30% peatmoss (by volume before mixing). Plants in each medium were fertilized at each or every third irrigation with 1 g·liter−1 of 20N-8.6P-16.6K fertilizer. Neither medium nor fertilization frequency affected flowering date of the first pseudobulb. Adding peatmoss to both types of bark resulted in taller first pseudobulbs. Peatmoss in the large bark promoted the production of more inflorescences and flowers (20) compared to the bark alone (11). Constant fertilization promoted the early emergence and development of the second pseudobulb and resulted in more inflorescences and flowers (21) than intermittent fertilization (12). Vegetatively propagated Phalaenopsis Taisuco Kochdian were planted in 0.5-liter pots with 1) equal volumes of no. 3 perlite, Metro Mix 700, and charcoal (PMC); 2) 100% large fir bark; or 3) 40% medium fir bark, 20% peatmoss, 10% each of no. 3 and no. 2 perlite, 10% vermiculite, and 10% ParGro rockwool (RM). Plants in PMC produced twice the number of new leaves and 1.5 -fold more leaf area than those in the large bark. PMC and RM resulted in similar shoot weights, but the latter enhanced flower count due to more lateral inflorescences. Most (80%) of the roots on plants in the bark were hanging out of the pots, whereas nearly all the roots remained in the pots with PMC. Although medium had no effect on flowering date, flowers on plants produced in PMC and RM were 10% larger than in those on plants produced in bark.
Jung-Yi Wu, Ting-Fang Hsieh, Chin-Yi Tsao, and Keng-Chang Chuang
Breeding for new phalaenopsis varieties has been conducted for many decades. With the efforts of breeders, a lot of varieties have been bred and sold in the market, including many colorful varieties with various flower sizes. However, new varieties are constantly being bred and selected every year and are expected to create new colors or new types that are different from those on the market. Breeding for indigo flowers has been a common goal for many breeders in the world. Currently, indigo
Woei-Jiun Guo and Nean Lee
In this study, effects of leaf age (20 to 240 days), plant age (4, 8, and 14 months after deflasking), and various day/night temperature regimes (16 to 33 °C) on photosynthesis of Phalaenopsis amabilis L. Blume var. formosa Shimadzu (Phal. TS97) leaves were investigated. The diurnal net CO2 uptake in Phal. TS97 leaves was measured and integrated to obtain total net CO2 uptake, which represents photosynthetic efficiency in plants performing crassulacean acid metabolism (CAM). Under all conditions, Phal. TS97 leaves performed typical CAM photosynthesis and reached their highest net CO2 uptake rate, ≈6 μmol·m-2·s-1, after 3 to 4 hours in the dark under a 12-hour photoperiod. When grown under 30 °C day/25 °C night temperature, the total net CO2 uptake of leaf increased with maturation and was highest at 80 days old, 20 days after full expansion. The CAM photosynthetic capacity of mature leaves remained high after maturation and began to decline at a leaf age of 240 days. The trend was consistent with malate fixation but the highest nocturnal malate concentration was observed in 100-day-old leaves. Young leaves or leaves from small juvenile plants had higher daytime CO2 fixation compared to mature leaves or large plants, suggesting that Phal. TS97 leaves progressed from C3-CAM to CAM during the course of maturation. The second newly matured leaf from the top had the highest net CO2 fixation when the newest leaf was 8 cm in length. Although plant age did not influence total CO2 uptake in the leaf, photosynthetic efficiency of leaves in small younger plants was more sensitive to high light intensity, 340 μmol·m-2·s-1 photosynthetic photon flux. The day/night temperature of 32/28 and 29/25 °C resulted in the highest total net CAM CO2 fixation in vegetative Phal. TS97 plants than higher (33/29 °C) and lower temperatures (21/16 °C).
James H. Keithly, Daniel P. Jones, and Henry Yokoyama
The growth-enhancing property of DCPTA was tested on transplanted seedlings of Brassolaeliocattleya × Hort. (Blc. Bryce Canyon × Lc. Pirate King), Dendrobium × Blume. Hickham Deb, Epidendrum radicans Pav. ex Lindl., Lueliocattleya × Rolfe Prism Palette `The Clown', and Phalaenopsis × Blume. [Pink Zebra × (Jutta Brungor × Music)]. After 3 to 6 months of greenhouse growth, plants treated with 30 μm DCPTA produced a 2- to 3-fold increase in root growth compared to the controls. Shoot growth, root: shoot ratio, and the survival of DCPTA-treated plants were increased significantly when compared with controls. Chemical name used: 2-(3,4-dichlorophenoxy)triethylamine (DCPTA).
Yin-Tung Wang and Tsung-Yao Hsu
Bare-root, mature, hybrid Phalaenopsis seedlings were dipped in one of three growth retardant solutions for 5 seconds or sprayed with a growth retardant 4 weeks following planting during inflorescence elongation. Dipping the entire plant in daminozide (2500, 5000, or 7500 mg·liter-1) before planting delayed flowering by 5-13 days, whereas foliar applications had no effect. Paclobutrazol (50, 100, 200, or 400 mg·liter-1) or uniconazole (25, 50, 100, or 200 mg·liter-1) dips did not affect the bloom date but effectively restricted inflorescence growth below the first flower (stalk). Increasing concentrations produced progressively less growth. Foliarly applied retardant treatments were less effective than dipping. Flower size, flower count, and stalk thickness were unaffected by treatments. Dipping in high concentrations of paclobutrazol (200 or 400 mg·liter-1) or uniconazole (100 or 200 mg·liter-1) caused plants to produce small, thick leaves. During the second bloom season, inflorescence emergence and bloom date were progressively delayed by increasing concentrations of paclobutrazol and uniconazole. Neither retardant affected flower count or size. Foliarly applied daminozide increased stalk length. In another experiment, foliar paclobutrazol treatment restricted stalk growth more effectively when sprayed before inflorescence emergence. Its effect progressively decreased when treatment was delayed. Paclobutrazol concentrations from 125 to 500 mg·liter-1 were equally effective in limiting stalk elongation when applied to the foliage. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); (E)-1- (p -chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol(uniconazole); (2 RS, 3 RS) -1-(4-chlorophenyl)-4,4-dimethyl-2-(1 H- 1,2,4-triazol-1-yl) pentan-3-ol (paclobutrazol).