**11.5 Dehydration**

Vitrification is a process of conversion of liquid into solid in the absence of crystallization. When the cells have properly undergone the process of slow freezing, it will result in vitrification where ice formation does not take place because here the aqueous solution is much concentrated which results in permitting the formation

#### *Germplasm Conservation DOI: http://dx.doi.org/10.5772/intechopen.96184*

of ice cubes. Instead, the water gets solidified into a glassy clear state. Dehydration during this process is achieved by the high concentration of osmotically active compounds like sugars, polyols performed in the sterile cabinet over silica gel [62]. In the process of dehydration, a reduction in the amount of water followed by the formation of ice and an increase in osmotic pressure occurs which ultimately depress the freezing point [63].

## **11.6 Rapid freezing**

Then plant material is placed in liquid nitrogen at a much lower temperature ranging from −300 to −1000 °C. Dry ice can also be similarly used in the process. The more quickly freezing is done the less will be the intracellular state of crystal formation. The methodology is simpler and easy to handle and can also be used for tips of potatoes and strawberry species. Dry ice can also be utilized for this purpose.
