The conservation and maintenance of plant biodiversity is an important issue relating to the global human population. The anthropogenic pressure, the introduction of foreign species, as well as native species and chronic weed invasion has striking special effects on plant diversity. As a result there is an increase in number of threatened species. For the food and medicine industry, plant biodiversity serves as a natural source of raw material. It supplies a variety of necessary raw materials and serves to provide new genetic information valuable for breeding programs furthermore for developing high yielding crops and resistant plants to environmental stresses (Rao, 2000). A huge amount of funds are spent annually to restock the lost biodiversity and many protocols are accessible recently. Unluckily, we are not seeing any enhancement in the condition of these plant species naturally and the number of endangered plant species is raising slowly but surely (Tripathi, 2008).
Public interest is getting more towards the preservation of plant genetic resources because
it appears as the only source for assuring sufficient availability of food stuff for future generation. On the other hand, the loss of biodiversity because of over exploitation of natural populations, deforestation, natural disasters, educational, political and financial issues, and cause a great hazard to plant genetic resources (Roberts, 1973). Tissue culture techniques and applications have been found to be practical in the conservation of a great number of rare (Holobiuc,et al., 2009.) and threatened (Pence, 2005) species which have little and vague responses to conservative means of propagation (Sarasan,et al., 2006). The typical culture environment can be efficiently developed for short to medium term storage of plant Germplasm, via rising intervals among subcultures in time-consuming growing species (Engelmann, 1997, 1998). For the protection of rare and endangered taxon, reproducing and conservation of plants with the use of In vitro cultures is one of the feasible methods. This multiplication of plants from the explants at culture media is termed as micro- propagation. The parts of plants which are used for multiplying purpose are very small as compared with traditional vegetative multiplying therefore it is known as micro-propagation. It has a lot of benefits. Such as: high multiplying rate, small stresses on quantity of initial plants, minute demands on room and multiplying of plants despite seasons of the year (Kováè, 1995). Disadvantages of tissue culture are economic (pricey tools, high ostentation) and multiplying of elevated number of genetically alike plants has no logic from defense point of view. There is a risk of occurrence of somaclonal variations that can be effectively eradicated by suitable techniques of micro-propagation. (Novák, 1990, George, 1993).According to the “Global Strategy for Plant Conservation”, 60% of threatened plant species should be available in Ex situ collection by year 2010, first in the country of source. Main concern should be towards the critically endangered species conservation in their countries of origin (Botanic Gardens Conservation International, 2000). Ex situ collections of genetic representatives provides material for research purposes and decrease impact to wild plant populations. It offers probable adaptive managing alternatives for in situ work also it maintains reserve to produce material for learning, reintroduction and other actions (Center for Plant Conservation, 1991, Guerrant,et al., 2004).
Plant micro-propagation technology has been expanded and reclassified constantly all through the last 30 years, and now it has become a major tool for conservation of plant genetic resource. Tissue culture methods have been productively used for both propagation and conservation of many rare and critically endangered undomesticated plants. These protocols are especially useful when a species is hard to propagate using classical methods (Fay, 1992, Wala and Jasrai, 2003, Panayotova, et al., 2008). In-vitro preservation of endangered species can propose substantial benefits for the swift cultivation of at threat species which have a partial or no reproductive capability and survive in threatened habitats. (Fay, 1992, Wala and Jasrai, 2003). The review briefly presents the important tissue culture techniques and their effectiveness for improved and efficient conservation of endangered plant species.
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