@ChatGPT Summarize the main difficulties during cryoconservation of plant tissues or plant cells. Explain commonly used techniques to overcome the aforementioned difficulties
Cryoconservation is a crucial technique in preserving the genetic diversity of plant species. However, there are several difficulties involved in the process. One of the main problems encountered during cryopreservation is the loss of cell viability caused by the formation of intracellular and extracellular ice crystals. These ice crystals can damage cell structures, including the cell membrane, organelles, and DNA.
To overcome these difficulties, several techniques have been developed. One commonly used technique is vitrification, which involves the use of high concentrations of cryoprotectants to prevent ice formation, and thus preserve cellular structures. Another technique is encapsulation-dehydration, which involves encapsulating the plant tissue or cells in an alginate matrix before dehydrating it.
Another challenge is to maintain genetic fidelity during cryopreservation. This can be addressed through the use of in vitro culture techniques, such as shoot regeneration from cryopreserved meristems or somatic embryos, or the use of genetic markers for verification of genetic integrity.
Moreover, the cryopreservation of recalcitrant plant tissues, such as seeds or embryos, is challenging as they contain high water content which causes ice crystal formation. To address this problem, partial dehydration or desiccation is done before cryopreservation.
In conclusion, the main difficulties during cryoconservation of plant tissues are the formation of ice crystals, loss of cell viability and genetic fidelity. However, several techniques such as vitrification, encapsulation-dehydration, in vitro culture, and partial dehydration have been developed to overcome these difficulties.
Reference:
- Sakai, A. (1995). Cryopreservation of plant germplasm. Cryptograms, Bryophytes, Lichens, Algae, Fungi, and Ferns, 181-198.