Cryopreservation of somatic embryos of ornamental plants

Abstract

Ornamental plants play a social and economic role in human society since antic ages, and its production consists about 78 % of total production. Thus, in situ and ex situ germplasm conservation techniques must be applied to preserve elite varieties. Since in situ strategies are more prone to environmental factors (e.g., biotic and abiotic stress) and ex situ approaches are open to cross-pollination or homologous recombination during gamete formation, currently in vitro strategies are the good complementary mechanism to avoid these problems. Among in vitro conservation techniques, cryopreservation seems to be the best candidate as it enables to preserve selected germplasm theoretically unlimited period of time with maintaining genetic stability, which is very important in ornamental plant cultivation. Besides, embryogenic cultures are used for in vitro propagation; the tissues are also utilized as target materials for gene transfer studies. These cultures have the potential to produce cisgenic or intragenic plants and cryogenic technology offers opportunities to conserve germplasm to introduce genes from crossable ornamental plants especially for cisgenesis. Thus cryopreservation also plays an important role in maintaining transgenic, cisgenic, or intergenic somatic embryos of ornamentals in a stable way. In this chapter, efficient cryopreservation technique including one-step and two-step freezing methods together with vitrification- and dehydration-based techniques for conservation of somatic embryos and related tissues of ornamentals is discussed. © 2017 Elsevier B.V., All rights reserved.