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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, METHODS, RESULTS. Meshes: Adaptation, Physiological, Conservation of Natural Resources, Cryopreservation, Cryoprotective Agents, Culture Media, DNA, Plant, Desiccation, Endangered Species, Genome, Plant, Genomic Instability, Plant Growth Regulators, Plant Shoots, Portugal, Random Amplified Polymorphic DNA Technique, Sucrose, Thymus Plant, Vitrification, Zeatin.
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Do cryopreservation of Thymus lotocephalus shoot tips and assessment of genetic stability? Context: Thymus lotocephalus is a rare endemic species from the Algarve, Portugal, and is legally protected by Portuguese and European legislation. The aim is to develop a cryopreservation protocol for T. lotocephalus shoot tips, as an alternative approach for the long-term conservation of this species. Several methods (droplet-vitrification, vitrification and encapsulation-dehydration) were tested. Conditions regarding the subculture period, cold-hardening and preculture were optimized. Cryopreserved shoot tips were also assessed for their genetic stability using RAPD markers. Droplet-vitrification presented the best results. The best regrowth of cryopreserved shoot tips obtained eight weeks after rewarming was 67%. This was accomplished with four weeks subculture period of in vitro-donor plants at 25 degree C, preculture of excised shoot tips for one day on MS medium containing 0.3 M sucrose, treatment in PVS2 for 60 min, and MS supplemented with 0.2 mg per L zeatin as recovery medium. The assessment using RAPD markers observed variation at a low frequency and shoots regenerated from cryopreserved apices showed normal development compared to the regular in vitro-grown shoots.
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Droplet-vitrification is thus a viable method for the cryopreservation of T. lotocephalus shoot tips. Final Decision: yes