198 W. A. VENDRAME AND A. A. KHODDAMZADEH
than 1 year without subculturing (Divakaran et al. 2006). PLBs ofCoel-
ogyne breviscapaencapsulated in 3% sodium alginate were stored in
4 ◦C for 60 d without loss of viability (Mohanraj et al. 2009). InCym-
bidium devonianum, using an encapsulated matrix with lower nutrient
content associated with low temperature allowed for increased storage
time (Das et al. 2011). PLBs ofCymbidiumhave also been used for
production of synthetic seeds by Teixeiria da Silva (2012). Mohanty
et al. (2013) encapsulated 60-d-old PLBs ofDendrobium nobileusing
3% sodium alginate, and by adding 7.5–12.5% sucrose and mannitol
in the encapsulating matrix they were able to store PLBs for up to 60 d.
Encapsulated PLBs have also been used for cryopreservation, such as in
Phalaenopsis bellina, cryopreserved by the encapsulation–dehydration
approach (Khoddamzadeh et al. 2011).
Development of synseed techniques will likely include other impor-
tant orchid species and hybrids in the near future. Studies on the
changes in encapsulation agents and stored encapsulated PLBs should
improve the potential to produce viable synseed technology for the
orchid industry.
V. CRYOPRESERVATION TECHNOLOGY
A. Concept
Approximately 100,000 plants species are currently threatened and face
extinction in the wild (BGCI 2005). According to The International
Union for Conservation of Nature and Natural Resources (IUCN), 8321
plant species were added in the red list of threatened species during the
period 1996–2004, with an increase of more than 60% of species classi-
fied as critically endangered (IUCN 2004). Therefore, the implementa-
tion of conservation strategies is essential to protect and conserve these
endangered species.
Plant genetic resources can be conserved efficiently by an appropri-
ate combination ofin situandex situconservation methods.In situ
conservation refers to conservation of plant resources in their natural
habitat, including national parks, reserve areas, and rangelands, while
ex situconservation is done outside of the natural habitat (Engelmann
and Engels 2002). Whilein situconservation is the most logical and pre-
ferred method, it is not always feasible; thereforeex situconservation
allows for a safe and alternative means for preserving genetic diversity.
Some approaches toex situconservation include seed storage, field
gene banks, and botanical gardens (Hartmann et al. 2002; Rao 2004).