Tissue culture has been applied to diverse research techniques such as viral elimination, clonal propagation, gene conservation, in vitro fertilization, mutation, induction for genetic diversity, genetic transformation, protoplast isolation and somatic hybridization, secondary metabolite production and other related techniques. The commercial production of ornamental plants is growing worldwide. Its monetary value has significantly increased over the last two decades and there is a great potential for continued further growth in both domestic and international markets. About 156 ornamental genera are propagated through tissue culture in different commercial laboratories worldwide. About 212.5 million plants including 157 million ornamental plants amounting to 78% of the total production were reported [1]. These plants are over exploited due to their high medicinal value and hence, propagation of the plants by tissue culture may be mandatory, which offers a greater potential to deliver large quantities of disease-free, true-to-type healthy stock within a short span of time. Biotechnological interventions for in vitro regeneration, mass micropropagation and gene transfer methods in forest tree species have been practiced with success, especially in the last decade. Against the background of the limitations of long juvenile phases and lifespan, developments of plant regeneration protocols of ornamental species are gaining importance. Ornamental industry has applied immensely in vitro propagation approach for large-scale plant multiplication of elite superior varieties. During in vitro condition, plantlets are grown under fixed and controlled environment in sterile formulated medium which contained macronutrients, micronutrients, vitamins and plant growth regulators. After the plantlets reached optimum growth in the culture containers after
a certain growth period, it can be transferred to ex vitro condition to allow continuous growth of the plantlets. As a result, hundreds of plant tissue culture laboratories have been set up worldwide, especially in the developing countries due to cheap labor costs.
Plant tissue culture media is normally rich in sucrose and other organic nutrients that can support organogenesis in plants but also the growth of many microorganisms (like bacteria and fungi). To overcome and prevent contamination in media preparation, sterilization should be done thoroughly. Sterilization of nutrient media can be done in an autoclave (large pressure cooker), less often by filtration and seldom by irradiation [2]. The container with the medium should be properly closed and autoclaved at 121ºC, 105 kPa, for 20 minutes. It also identified that good sterilization relies on time, pressure, temperature and volume of the object to be sterilized [2]. The sterilized nutrient media should be stored in a sterile box that has previously been disinfected with 70% alcohol [2]. Some of the plant growth regulators such as giberellic acid (GA3), zeatin, abscisic acid (ABA), urea, certain vitamins, pantothenic acid, antibodies, colchicines, plant extracts and enzymes used in tissue culture is thermolabile. These compounds should not be autoclaved and filter-sterilization is often used if a thermolabile substance is needed in a nutrient medium.
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