Cryopreservation of cold-acclimated mint (Mentha spp.) shoot tips using a simple vitrification protocol

Area of Science:

• Plant Biotechnology
• Cryopreservation
• In Vitro Conservation

Background:

• Mint species (Mentha spp.) are valuable for their aromatic compounds.
• Effective methods for long-term conservation of diverse mint accessions are needed.
• Cryopreservation offers a promising solution for preserving plant genetic resources.

Purpose of the Study:

• To evaluate the efficacy of a simple vitrification protocol for cryopreserving Mentha x piperita, M. x villosa, and M. spicata.
• To investigate factors influencing plant regrowth after cryopreservation, including pre-culture conditions and cryoprotective treatments.

Main Methods:

• Shoot tips from in vitro-grown mint plantlets were used.
• A simple vitrification protocol utilizing aluminum foil as a carrier was employed.
• Plant pre-culture conditions (temperature regimes), loading solutions, loading times, and the use of Plant Vitrification Solution 2 (PVS 2) were tested.

Main Results:

• Pre-culturing at an alternating temperature regime of 25/-1°C significantly enhanced plant regrowth compared to constant temperatures (20°C or 25°C) or a 25/15°C regime.
• Mean regrowth levels increased from 36% at 20°C to 69% under alternating temperatures, with a maximum regrowth of 89%.
• Loading solution, loading time, and the presence of PVS 2 droplets did not significantly affect plant regrowth.

Conclusions:

• Alternating temperature pre-culture (25/-1°C) is crucial for optimizing vitrification-based cryopreservation of Mentha species.
• The simple vitrification protocol is effective for mint conservation.
• Regrown shoots rooted readily, enabling successful transfer to soil and ex situ conservation.