Mangosteen (Garcinia mangostana L.) and longkong (Lansium
domesticum Corr.) are the major fruit crops cultivated in the south of
Thailand. Fruits of these species have superior gustatory qualities.
Although, genetic variation of mangosteen and longkong are minimal and
no cultivars have been reported [1-4], their germplasm should be
conserved for the future breeding program.
At present, seed stores are the most popular germplasm
conservation method, because it is easy for storage and management.
However, there are large numbers of important tropical and sub-tropical
fruits which produce recalcitrant seeds that quickly lose viability and
cannot survive under desiccating conditions, hence conventional seed
store strategies are not possible [5-7]. For this purpose, in vitro
conservation would be the most convenient and reliable method compared
to field conservation which requires much more space and labor for
maintaining the collections that may experience damage due to natural
disasters, pests and diseases [6,8,9]. Furthermore, tissue culture systems
can propagate plant material with high multiplication rates in an aseptic
environment without genetic variation and convenient for international
exchange of germplasm [10]. In vitro conservation has already been
applied to many species including tropical crops. Although several
methods are employed, depending on the situation, the suppression of
explant growth is essential for extending the duration of conservation. To
suppress the growth rate of the plant in vitro, the addition of substances
with osmotic properties such as mannitol can be used. As well as under
field conditions, the growth of plant material could be reduced by the
application of growth retardant under in vitro conditions [6-9,11].
This study was conducted to analyze the effects of growth
retardants and tissue desiccation treatment on the growth suppression of
mangosteen and longkong shoots to determine the appropriate conditions
for in vitro conservation.
MATERIALS AND METHODS
Plant Material
Proliferation of mangosteen culture was established by aseptically
cultured seeds on modified Murashige and Skoog (MMS) medium [12,13]
supplemented with 5 mg/l 6-benzylamino purine (BA), 30 g/l sucrose and