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ARS Home » Pacific West Area » Corvallis, Oregon » National Clonal Germplasm Repository » Research » Publications at this Location » Publication #214614
Title: A Comparative Study of Three Cryopreservation Protocols for Effective Storage of In Vitro-Grown Mint (Mentha Spp.)

Author
item UCHENDU, ESTHER - OREGON STATE UNIVERSITY
item Reed, Barbara

Submitted to: CryoLetters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2007
Publication Date: 6/20/2008
Citation: Uchendu, E., Reed, B.M. 2008. A comparative study of three cryopreservation protocols for effective storage of in vitro-grown mint (mentha spp.). CryoLetters. 29(3):181-188.

Interpretive Summary: Four mints from the tissue culture collections of the USDA-ARS National Clonal Germplasm Repository (NCGR), Corvallis, were cryopreserved in liquid nitrogen using three standard protocols. All four genotypes responded well to a controlled rate cooling protocol. Regrowth following the controlled cooling protocol (93%) was better than for the other two techniques. Overall, regrowth of the four mints ranged from 60% to 90%. The overall results of this study compare favorably to other techniques used to cryopreserve mint. These improved results may be due to a combination of favorable growth conditions, cold acclimation and recovery medium. These results indicate that the controlled cooling technique was the most successful; however, recovery of shoot tips from the other techniques was usually high enough that they could also be used for liquid nitrogen storage of a range of mint types.

Technical Abstract: This study was designed to determine the response of diverse mint genotypes to three commonly used cryopreservation techniques. Four mints [Mentha x piperita nothosubsp. citrata (Ehrh.) Briq.; M. canadensis L.; M. australis R. Br, and M. cunninghamii Benth] were cryopreserved using the three standard protocols: controlled rate cooling (CC), encapsulation dehydration (ED) and PVS2 vitrification (VIT). All four genotypes responded well to the controlled rate cooling protocol. Pooled data showed that regrowth of mint species following controlled rate cooling (93%) was significantly (p < 0.0001) better than encapsulation dehydration (71%) and vitrification (73%). Genotype specific response to the individual protocols showed that there were significant differences in the recovery of Mentha x piperita nothosubsp. citrata and M. australis with CC > VIT > ED. There were also significant differences in the recovery of M. cunninghamii and M. canadensis, with CC and ED significantly better than VIT. Regrowth of the shoot tips of these mints ranged from 60% to 95% for all but one treatment. The overall results of this study compare favorably to other tested techniques. These improved results may be due to a combination of favorable growth conditions, cold acclimation and recovery medium. Controlled rate cooling was the most successful technique for the storage of these diverse mint genotypes; however recovery of shoot tips from VIT and ED was high enough that these techniques could also be used for cryogenic storage of mint germplasm.