Cryopreservation as a tool used in long-term storage of ornamental species – A review

Abstract

The market for ornamental plants is growing every year, becoming an important part of the economy. Every year hundreds of new cultivars, replacing the current assortment, are produced. However, since consumer preferences are changing rapidly, the cultivars considered old-fashioned today may become popular once again. They are also a valuable breeding material source. Bearing that in mind, there is a great need to develop a strategy for their long-term conservation. Storage in gene banks under in vitro cultures, although offering many advantages, is expensive and threatened with somaclonal variation and contamination loss. Cryopreservation is believed to be a more promising method. It has been successfully used with many agricultural species. Unlike micropropagation, cryopreservation has not yet found wider employment with ornamental plants. The upcoming years and progress in cryobiology may, however, change this situation and broaden the potential of cryoconservation. Over years several freezing methods have been introduced. The first one developed, based on slow cooling, had limited usefulness in temperate species. Today the encapsulation-dehydration technique is most often used with ornamental plants. In the future, however, combined techniques will probably be the most popular. So far insufficient attention has been paid to the problem of the genetic stability of cryopreserved ornamental species, especially chimeras. The aim of this paper is to present different cryopreservation techniques and their use for the storage, protection and breeding of ornamental plants.