Cryopreservation of Capsicum annum var. grossum using encapsulation/dehydration of apices produced in vitro

Shoot tips of in vitro propagated plantlets were cryopreserved using encapsulation/dehydration procedures. Shoot tips were excised under filter sterilized antioxidants solution (0.2M phosphate buffer, pH 5.7 supplemented with 5g/1 ascorbic acid and 15g/1 sodium borate). They were drawn up into a sterile 10 $\textrm{cm}^3$disposable pipette and were dropped into the culture medium with 2.5w/v Na-alginate, then into 100mM CaCl$_2$.2$H_2O$. Encapsulated shoot tips were transferred into 10㎤ of liquid culture medium with a range of sucrose concentrations (0.25-1.0M) and were incubated in dark for 24 hours in 18C at 40rpm. Beads were then dehydrated in silica gel for different time intervals (1-24 hours). Then they were freeze dried either rapidly (plunge directly into liquid N2 or in two stages (samples were kept at 20C for 10 minutes, then reduced to 35C at 1C per minute. Then, plunge into liquid $N_2$). The influence of sucrose and silica gel pre-treatment on pre- and post-freeze shoot growth was examined.(중략)