Submitted to: Cryopreservation of Plant Germplasm II
Publication Type: Book / Chapter
Publication Acceptance Date: 1/20/2002
Publication Date: 3/20/2002
Citation: Towill, L.E. and Y.P.S. Bajaj (eds.) 2002. Cryopreservation of Mentha (Mint). . pp. 151-163. In L.E. Towill and Y.P.S. Bajaj (eds.) Cryopreservation of Plant Germplasm II. Biotechnology in Agriculture and Forestry Series Vol 50, Springer, London.
Interpretive Summary: There are several mint species used in commerce and all are maintained vegetatively to retain the unique characteristics of the genotype. Cryopreservation is valuable to provide unchanged stock materials should original lines become lost or diseased, and has been achieved for several mint species using two-step cooling and vitrification methods. Although details of the methods could be optimized for each species, the methods could be applied across species because of the fairly high levels of survival obtained.
Technical Abstract: The genus Mentha comprises several species that are economically important for oil production and fresh or dried herbal products. The major species used commercially are peppermint and spearmint. Mint is usually vegetatively propagated and is easily rooted; however, pot or field maintained materials are susceptible to disease. Fortunately most species are easily placed into culture and micropropagated. For germplasm considerations, cryopreservation allows a backup for lines to protect against loss. There are very little data on preservation of seeds or pollen. Shoot tips from either in vitro or ex vitro plants have been cryopreserved by two-step cooling and vitrification methods, the latter being favored because of its technical simplicity. Both methods have been effective with clonal lines from several Mentha species. Similar levels of viability have occurred over 1 year of storage, although obviously much longer durations are projected. Cracking of the glass within the storage vessel did not produce visible damage and did not affect viability of shoot tips. Interestingly, samples did not show increased damage during 3 cooling and warming vitrification cycles, suggesting that the cells contain a rather stable glass under the exposure conditions imposed.