Micropropagation of Anthurium spp.

Micropropagation as an alternative method to conventional propagation, the culture of somatic cells, tissues and organs of plants under controlled conditions is a suitable way to produce a large number of progeny plants which are genetically identical to the stock plant in a short time. The important property of the plant cells is totipotency which is a capacity to produce the whole plant from different plant parts. Micropropagation has some features to be chosen in commercial production such as multiplicative capacity in a relatively short time, healthy and disease-free production capacity and ability to generate population during a year [1-5].

The genetic pattern of the plant is key element to select the propagation method. Using micropropagation techniques in plant biotechnology applications are costlier than conventional propagation methods. Propagation by using in vitro techniques instead of conventional methods offer some advantages like utilizing small pieces of plants called as explants to maintain the whole plant and increase their number. The main point is to evolve new strategies to
lower the time and cost consumed per plant [2,3]. In tissue culture applications selection of initiating material is important in the beginning of the culture. Therefore it is easy to provide virus-free clones in a short time. Production of plants during all year long independent of seasonal changes, long storage periods make micropropagation preferable to propagate plants in short time. There are also some disadvantages of micropropagation. Adaptation of cultured plants to the environmental conditions need transitional period to allow the plants to produce organic matter by photosynthesis [2,4].

The main methods of in vitro propagation can be classified in two groups:

1. Propagation from axillary or terminal buds
2. Propagation by the formation of adventitious shoots or adventitious somatic embryos

The meristem and shoot tip cultures are used to establish virus-free plant culture. Many important horticulture crops were propagated by meristem culture for rapid growth and virus elimination. Adventitious shoots or adventitious somatic embryos are established directly or indirectly. Cultures are directly started with the excised explants from the mother plant tissues for organogenesis or embryogenesis. If shoots or embryos regenerate on previously formed callus or in cell culture, they are called as indirect organogenesis or embryogenesis [3,6,7].

When propagation occurs via an indirect callus phase, the genetic identity of the progenies decreases. This is an important problem in commercial propagation to affect the uniformity of progenies. Callus formation also increases the somaclonal variation. Increasing of somaclonal variation incidence is a crucial result of long term period of callus growth. Origin of the callus also causes somaclonal variation.

Propagation from axillary or terminal buds is the most ensurable method to have the highest genetic stability during in vitro propagation of plants.

George et al. [2008] described five stages of micropopagation which are mother plant selection and preparation [Stage 0], in vitro culture establishment [Stage 1], shoot multiplication [Stage 2], rooting of microshoots [Stage 3] and acclimatization [Stage 4]. These stages are necessary for a successful micropropagation.

Establishing aseptic culture conditions can be classified as Stage 0 which contains pre-surface sterilization applications of explants to reduce contamination of stock plants. The success of Stage 2 depends on different factors such as plant species, cultivar or genotype, plant growth regulators, the ingredients of the medium and physical culture conditions. Stage 3 is responsible of rooting of microshoots. It depends on the factors given in Stage 2. Transplantation of rooted shoots to the environment is the main step of Stage 4. This is also the important part of micropropagation. Acclimatization needs to be well controlled to avoid loss of propagated plants [4,5].

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