Production of synthetic seed by desiccation and encapsulation

Purdue University Department of Horticulture 47907 West Lafayette Indiana; University of Delaware Department of Plant Science 19717 Newark Delaware; Rural Development Administration Agricultural Sciences Institute 440-707 Suwon Korea
In Vitro Cellular & Developmental Biology - Plant (Impact Factor: 1.14). 25(12):1167-1172. DOI: 10.1007/BF02621269

ABSTRACT Producing synthetic seed of carrot consists of coating in-vitro grown embryos with a synthetic seed coat such as Polyox WSR-N
750, drying under controlled conditions, and hardening to prevent precocious germination. Survival of such embryos declines
over time. Similar procedures have also been used with celery. Somatic embryos have several advantages compared to conventional
tissue culture which include proliferacy, singulation, and the development of bipolar structures. The factors which most limit
the use of synthetic seeds are the inability to use such procedures with economically important genotypes, lack of understanding
of the maturation of somatic embryos and poor conversion rates to greenhouse and/or field.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Premise of research. Orchids are among the most enigmatic of plant species. Yet the Orchidaceae comprises more species at risk of extinction than any other plant family. The collection and storage of orchid germplasm—principally seeds and associated mycorrhizal fungi but also protocorm-like bodies using encapsulation and vitrification techniques—allows for secure ex situ conservation. This article reviews the approaches and techniques used for the ex situ conservation of orchid germplasm, with a focus on seed banking and the use of cryopreservation techniques to improve the longevity of germplasm. Pivotal results. It is increasingly apparent that cryopreservation—the storage of germplasm at ultra-low temperatures (e.g., in liquid nitrogen)—is required for the long-term and low-maintenance conservation of all types of orchid germplasm. For orchid seeds, desiccation tolerance is common, but longevity in storage is poor. Cryopreservation of orchid seeds shows promise, but some complexities in low-temperature storage behavior still require explanation and resolution. The application of more advanced cryopreservation techniques, including encapsulation-dehydration and vitrification, is becoming increasingly common. These techniques provide for the simultaneous storage of orchid propagules with their compatible fungus, while for seeds, vitrification techniques show potential for improving tolerance to the stresses of cryopreservation. Conclusions. A renewed focus on describing the low-temperature storage physiology of orchid seeds to more precisely define the relationship between seed water content, storage temperature, and seed survival is required, as is perhaps the wider adoption of the use of cryoprotectants for seeds. This research, coupled with the development of improved methods of seed viability testing, will support the growing work of germplasm banks to protect orchid biodiversity in the face of habitat loss and potential species extinction.
    International Journal of Plant Sciences 01/2014; 175(1):46-58. · 1.54 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Complex coacervation of alginate–chitosan and alginate–gelatin were used to develop two-coat systems for the encapsulation of Spathoglottis plicata seeds and protocorms (top-shaped structures formed after seed germination of orchids). Both the seeds and the protocorms could withstand the encapsulation treatments with high viability. About 54% of seeds and 40% of large protocorms (1.6–2.0 mm) were able to tolerate a 6-h desiccation treatment. However, viability of the small protocorms (0.7–0.9 mm) was greatly reduced if they were desiccated before encapsulation. Encapsulation after desiccation significantly increased the percentage viability of seeds and protocorms. Treatment with abscisic acid (ABA, 10−5M) before desiccation and encapsulation resulted in high percentage viability in seeds and large protocorms whereas the small protocorms were found to be less tolerant to the treatments. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:635–639, 1998.
    Biotechnology and Bioengineering 09/1998; 59(5):635 - 639. · 4.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Protocol for direct somatic embryogenesis from leaf explants of economically important species of Dianthus, viz. D. caryophyllus, D. barbatus and D. chinensis has been developed. Murashige and Skoog’s (MS) liquid medium supplemented with 2,4-D (1mg/l) was used for direct induction of somatic embryogenesis without an intervening callus phase. Initially globular structures were observed after 21 days of culture of leaf explants in liquid medium. Development of embryos to heart and torpedo stages was achieved in the liquid medium incorporated with polyethylene glycol (PEG 6000) at a concentration of 2.5%. Embryo maturation was further promoted by addition of casein hydrolysate (CH) (200mg/l) in MS liquid medium. Embryos germinated to form plantlets on solid MS medium supplemented with GA3 (1mg/l). Regenerated plants with well-developed root and shoot systems were successfully transferred to field conditions.
    Scientia Horticulturae 01/2003; 98(4):449-459. · 1.40 Impact Factor