In this study, the effect of various factors, including the physiological s
tate of mother-plants and parameters of the encapsulation-dehydration proto
col (cryoprotective treatment, freezing protocol) on the regrowth of shoot
tips of kiwi in vitro plantlets was studied. The optimal protocol establish
ed was the following: shoot tips were sampled on mother-plants after a one
month cold-acclimation period at 5 degreesC. For preculture, which was perf
ormed at 5 degreesC, encapsulated shoot tips were transferred at 24-hour in
tervals on solid media with increasing sucrose concentrations, from 0.5 to
1.0M. Beads were then desiccated to 26% moisture content (fresh weight basi
s), prefrozen from 0 degreesC to -40 degreesC at 0.2 degreesC/min and immer
sed rapidly in liquid nitrogen. No differences were noted between in vitro
plantlets produced from cryopreserved and control shoot tips as regards lea
f color, average height, multiplication rate and peroxidase zymogram patter
n. Apices of 3 kiwi accessions were frozen using the above protocol with re
growth percentages ranging between 22 and 56%.