CRYOPRESERVATION OF IN VITRO-GROWN SHOOT TIPS OF MORUS SPP. AND PYRUS COSSONII REHDER BY ENCAPSULATION-DEHYDRATION

In vitro grown shoot tips of Morus alba, M. indica, M. sinensis and Pyrus cossonii Rehder were cryopreserved by the encapsulation-dehydration technique.
In Morus spp. the shoot tips were excised from 2 week cold acclimated in vitro plantlets.
Encapsulated shoot tips were pretreated in 0.1, 0.3, 0.5 or 0.75 M sucrose for 20 h; desiccated for 6 h under laminar air flow, plunged in liquid nitrogen and rapidly warmed.
The combination of osmotic dehydration in 0.75 M sucrose and air dehydration for 6 h produced 50-80% regrowth.
However, cryopreserved shoot tips showed 30-35% regrowth when dehydrated to ~20% moisture content.
The encapsulation dehydration method was suitable for mulberry cryopreserved shoot tips with reasonable recovery in M. indica (35%), M. alba (35%) and M. sinensis (30%). In P. cossonii Rehder, the in vitro plantlets were cold acclimated for 1 or 3 weeks.
Encapsulated shoot tips were pretreated in 0.75 M sucrose for 20 h.
The beads were desiccated for 4 h on silica gel, then plunged in liquid nitrogen and rapidly warmed.
Osmotic dehydration produced 60% regrowth.
Cold acclimation was effective in regrowth of cryopreserved shoot tips.
Three week cold acclimated shoot tips resulted in 40% recovery, while there was no regrowth in non- or 1 week cold acclimated shoot tips after liquid nitrogen treatment.

I International Symposium on Cryopreservation in Horticultural Species

S. Gupta

cryopreservation, encapsulation-dehydration, mulberry, Pyrus, shoot tip

https://doi.org/10.17660/ActaHortic.2011.908.41