208 W. A. VENDRAME AND A. A. KHODDAMZADEH
cryopreservation studies with 10 different orchid species showed that
seeds recovered well from cryopreservation, maintaining their initial
viability (Pritchard 1984). However, differences in seed lots can return
different viability results after cryopreservation. This was the case of
a study performed by Seaton and Hailes (1989) where viability in one
lot ofGuarianthe aurantiacaseeds stored for 50 d at –18◦C was lost
almost completely. In contrast, seeds of the same species, but a different
lot stored for 400 d under the same conditions as previously described
showed high viability (Thornhill and Koopowitz 1992).
Recent advances in orchid seed cryopreservation have provided sim-
ple and effective protocols for long-term storage of orchid seeds under
ultra-low temperatures. Two cryoprotectants were evaluated for the
cryopreservation of seeds ofDendrobiumhybrids, phloroglucinol and
Supercool X1000 (Galdiano et al. 2012). Results showed that the use of
1% phloroglucinol added to a pre-vitrification solution (PVS2) returned
highin vitrogermination rates (79%) for the seeds after removal from
liquid nitrogen. In contrast, the addition of 1% Supercool X1000®had
no effect in seed germination.
Using the encapsulation–dehydration technique, Surenciski et al.
(2012) cryopreserved immature seeds ofCyrtopodium hatschbachii,
observing a 64% increase in seed germination and survival of the accli-
matized plants after cryopreservation.
Cryopreservation of orchid seedsviavitrification has been shown
to be a simple, safe, and cost-effective method. However, exposure
to excessive low temperatures and certain chemicals present in cry-
oprotectants may lead to potential somaclonal variation (Harding 2004)
caused by the genetic instability of explants (Panis and Lambardi 2006).
In one recent study, the genetic stability of cryopreserved seeds from
Dendrobiumhybrids was evaluated using flow cytometry, and showed
that the genetic integrity of seedlings recovered was maintained and no
abnormalities were observed (Galdiano et al. 2012).
C. Protocorms
Studies on protocorm cryopreservation have addressed both species
and hybrids. The conservation of orchid protocorms is important for
breeding and conservation programs as they provide a fast means of
plant regeneration (Ishikawa et al. 1997).
Among different factors affecting the recovery of cryopreserved pro-
tocorms, the culture media plays an important role, as demonstrated
by Popova et al. (2003). The authors showed the effect of different
culture media on the development of protocorms from cryopreserved