Search Results

You are looking at 51 - 60 of 328 items for :

  • Refine by Access: All x
Clear All
Free access

Woei-Jiun Guo, Yu-Zu Lin, and Nean Lee

Phalaenopsis orchids have become one of the most valuable potted ornamental plants around the world. According to the U.S. Department Agriculture’s (USDA’s) Floriculture Crops Summary, potted orchids account for $191 million in wholesale revenue in

Free access

Monica Haddix, Marihelen Kamp-Glass, and Charles Raczkowski

Encyclia is a genus of orchids with four members native to Florida that are Endangered or commercially exploited. If a commercial orchid tissue culture media was found that could be used to propagate Encyclia, the resulting plants could be introduced into protected habitats to increase the wild populations or could be grown commercially to lessen the demand for collected plants. Six month Encyclia tampensis (Lindl.) seedlings were grown in Orchid Maintenance/Replate Medium w/Banana and Charcoal with 6 g·L–1 agar (C), ½ strength Orchid Multiplication Medium with 6 g·L–1 agar and 10 g·L–1 charcoal (OM), Knudson C Orchid Medium – Morel Modification with 6 g·L–1 agar and 10 g·L–1 charcoal (K), or Vacin and Went Modified Orchid Medium w/agar and sucrose with 10 g·L–1 charcoal (VW) for seven weeks. Plants grown in OM and VW media both produced more shoots and roots (7.56 leaves, 1.92 shoots and 6.67 leaves, 1.76 shoots respectively) than the control medium (5.87 leaves, 1.70 shoots) with OM producing the highest averages. Plants grown in the K medium averaged significantly less shoots and leaves than the other three media (4.94 leaves, 1.35 shoots).

Open access

W.C. Lin and J.M. Molnar

Abstract

Alstroemeria plants were grown under 10, 12, 14, 16, 18, and 24 hour photoperiods by employing an 8-hour natural day and low intensity incandescent lighting as a daylength extension. The production of flower stems was increased to a maximal level by extending the photoperiod to 16 hours in ‘Orchid’ and in ‘Regina’. Under 16 hours high-intensity supplementary lighting with high-pressure sodium (HPS) lamps, the production of flower stems in ‘Orchid’ increased by 49% in the first year and 36% in the 2nd year. ‘Regina’ flower stems increased by 26% in the first year and 16% in the 2nd year. HPS lighting increased the number of flowering shoots per square meter from 166 (control) to 262 in ‘Orchid’ and from 10 to 21 in ‘Regina’ during the period November to February.

Open access

James E. Henrich, Dennis P. Stimart, and Peter D. Ascher

Abstract

Seeds of 29 terrestrial orchid species representing 15 genera were surface sterilized by immersion in 0.5% sodium hypochlorite containing a wetting agent, washed, sown on a completely defined, semisolid embryo culture medium containing macro- and microelements, sucrose, amino acids, and vitamins, and incubated in the dark at 25°C. Six months after sowing, 16 species from 9 genera germinated and continued development while 13 species from 10 genera failed to germinate. Species of Cypripedium, Goodyera, Platanthera and Spiranthes differed in response in that one or more of each germinated and one or more did not. Seedling development was similar for most germinating species and progressed to the formation of a shoot or shoot initial in all but one. Apparently the mycorrhizal association thought to be required for terrestrial orchid seed germination and early seedling development can be replaced with aseptic culture on a completely defined medium for many terrestrial orchids.

Free access

Thomas W. Zimmerman and Jacqueline Kowalski

The Sandy Point Orchid (Psychilis macconelliae) is listed as an endangered orchid species by the U.S. Virgin Islands Dept. of Planning and Natural Resources. This orchid grows naturally on the southern dry and wind-swept slopes found on the east-end of St. Croix. It can be found growing among cacti and bromeliads. Due to disturbance to the native habitat from land development, private collectors, and natural disasters, the population has diminished. Tissue culture is being successfully used in a conservation effort for this endangered species. Maturing seed pods were collected and surface disinfested and established in vitro. The medium consisted of one half Murashige & Skoog salts, Nitsch & Nitsch vitamins, 20 g/L sucrose, 2 g/L soy peptone, 5 g/L activated charcoal and 8 g/L agar. Seeds were spread on the medium in 15 × 100-mm petri plates and grown at 25 °C under a 16-h photoperiod. Seed germination occurred within 2 months with the development of protocorms. Leaves and roots developed by 5 months, at which time they were separated and transferred to fresh medium. At 8 months, they were established in a greenhouse and released back into their environment within 12 months. In vitro germination of the Sandy Point Orchid seed is an effective way of conserving this endangered species.

Free access

Laura A. Dellevigne, Jeffrey W. Adelberg, and Peter Vergano

Three-dimensional polypropylene enclosures have been fabricated for the in vitro culture and ex vitro growth of Cattleya orchid propagules. The enclosures consist of: 1) microporous polypropylene membrane for nutrient transfer between liquid media and the growing tissue. 2) molded polypropylene side wall sized for growth of Cattleya orchid plants and flanged to allow heat seals with membranes, and 3) polypropylene membrane(s) top member for light and gaseous transmission. Three commercial clones of Cattleya have been sealed into these enclosures and grown for eight months on unmended MS medium. Contaminated liquid media was effectively isolated from the propagules within the sealed enclosures, and following a bleach treatment with sterile rinses, propagules were returned to aseptic culture. Greenhouse growth of plant tissues in these enclosures will be discussed. Optimization for growth of Cattleya has begun with studies of gas, light and temperature regimes within the sealed enclosures and a comparison of growth on two different nutrient formulations.

Free access

Joe DeFrank* and James J.K. Leary

Two experiment were conducted in 1999 and 2000 to determine the response of orchid cultivars, grown as potted plants, to postemergence herbicides. In a film covered commercial nursery in Pahoa, four orchid cultivars were exposed to five sequential herbicide applications. The cultivars used were: Emma White (Dendrobium), Wildcat Blood Ruby, Volcano Queen (both Oncidiums), and SuFun Beauty (Vanda). The herbicides evaluated in this experiment were diuron and clopyralid applied at the anticipated (1×), 2×, and 4× use rate. Spray applications were made directly to crop foliage using a spray to wet application. The first application was applied on 11 Nov. 1999 with sequential applications made at 20-, 208-, 73-, and 69-day intervals for a total of five sprays. Orchid dry weight accumulation was not significantly reduced and all cultivars responded in a similar way. “Emma White” was the only cultivar to express abnormal growth to clopyralid in the form of J-shaped flower spikes and deformed flowers. The other three cultivars did not show any noticeable injury in response to any of the spray applications. A follow up experiment was conducted on the dry leeward coast of Oahu in a commercial saran house. Diuron was the only herbicide evaluated at one and four times the anticipated labeled use rate. The first application was made on 27 Apr. 2000 with sequential applications made at 50-, 21-, 70-, and 66-day intervals for a total of five sprays. The orchids selected for this experiment included nine Dendrobiums and one Vanda. Treatments were made directly to plant foliage using a spray to wet application. Whole plant dry weight accumulation of the 10 cultivars responded in a similar way and no herbicide treatment reduced dry weight accumulation in comparison to untreated plants.

Free access

Michael Compton and Timothy Zauche

Lady slipper orchids have great potential as a perennial bedding plant in temperate-zone climates Unfortunately, many gardeners fear these species because of their high cost and perceived difficulties associated with growing plants outdoors. The former factor can be addressed by improving the production of plants at the wholesale level. Growers contest that sphagnum peat and coconut coir are poor organic addenda for these species due to their natural acidity. Anaerobic digestion-derived biosolids (ADB) are not acidic like sphagnum peat or coconut coir, and may be the perfect organic addendum for the culture of ladyslipper orchids. Hence, 3-year-old plants of showy (Cypripedium reginae) and yellow ladyslipper (Cypripedium parviflorum var. pubescens) orchids were grown in soilless potting mixes containing vermiculite and perlite plus various concentrations and combinations of ADB and coconut coir. Plants were grown in the greenhouse at 70 ± 10 °F and received normal light and photoperiod during Summer 2005. Growth, as assessed by the dry weight of dormant stem tissue, of showy ladyslipper potted in media containing ADB was three- to four-times greater than those grown in media containing coconut coir. Growth was similar among yellow ladyslippers grown in media containing ADB or coconut coir due to the fact that these plants had produced all their stem growth for the season before the experiment was initiated. ADB has great potential as an organic addendum to horticultural growing media used for the culture of Cypripedium species. Use of anaerobic digester-derived biosolids in horticultural growing media is a protected intellectual property and available for license through the WiSys Technology Foundation.

Free access

Erika Szendrak and Paul E. Read

The effects of organic compounds most commonly used for orchid micropropagation and the physical condition of the medium were investigated for the development of young temperate orchid protocorms. Separate experiments were conducted with five different temperate orchid species: Dactylorhiza fuchsii, Dactylorhiza maculata, Dactylorhiza majalis, Orchis morio, and Ophrys lutea. Small 2- to 4-mm-wide protocorms were placed in baby food jars (three per jar) containing 50 ml modified FAST medium (Szendrak and R. Eszki, 1993) supplemented with one of eight treatments in a split-plot design with five replications. Both the liquid medium (gyrotary shaker, 125 rpm) and the gelled medium (8 g agar/L) were supplemented with one of the following compounds: 2 g peptone/L; 100 ml coconut water/L; 1 g casein+1 g lactalbumin/L; and 10 g glucose/L as a treatment with a defined compound. All treatments were kept in the dark at 25°C. The number of protocorms/jar were counted weekly over a 6-week-long period and the size and fresh weight of protocorms were measured at the end of the 6th week. In most cases, the liquid medium increased proliferation and the size of the protocorms. However, generally after the 4th week on liquid medium, the development of the protocorms often stopped, but it continued on the gelled medium till the end of the experimental period. The media supplemented with the undefined organic compounds showed a much better effect than the medium supplemented with glucose. Generally peptone and coconut water led to the best development of protocorms, but this varied with species. The development of protocorms into plantlets was normal in all cases.

Free access

Piyada A. Tantasawat, Apinya Khairum, Kitiya Arsakit, Oythip Poolsawat, Paniti Pornbungkerd, and Chitpan Kativat

Dendrobium is one of the most popular ornamental and commercial orchids in Thailand, which is currently one of the world’s largest producers and exporters ( Hotrawaisaya et al., 2014 ). Various techniques are used to propagate dendrobium (e