Conservation of medicinal plant

Conservation of medicinal plant

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  CONSERVATION OF MEDICINALPLANTS SATYAJIT GHOSH B. PHARM 4TH SEMESTER
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   Methods forconservation: -  In Situ conservation of medicinal plants: - i. In-situ method of conservation deals with the “on-site conservation” of the wild genetic diversity in natural habitat. In India, the conservation of forest areas preserves through protected areas like National Parks, Wildlife Sanctuaries and Biosphere Reserves. ii. The Government should prepare a policy at national level on the conservation and utilization of medicinal plants in protected areas. This type of conservation is achieved both by setting away areas as nature reserves and wild nurseries and by ensuring that as many wild species as possible can still survive in managed habitats, like farms and plantation forests. A- Natural Parks – Natural Parks are protected areas of important wild resources created to preserve and re-store biodiversity. Around the world, more than 12,700 protected areas have been established. Conservation methods In situ conservation Natural reserves Wild nurseries Biosphere reservation Ex situ conservation Botanical gardens Seed banks In vitro technology Germplasm technology Cryopreservation Cold storage Low pressure storage Plant tissue culture Cell suspension Zygotic embryo Adventitious bud
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  Conserving medicinal plantsin their natural habitat requires evaluating the contributions and ecosystem roles of individual habitats. Examples: - Velavadar national park, Gujarat, Ranthambore national park, Rajasthan, Corbett national park, Uttarakhand. B- Wild nurseries – The populations of medicinal plants are under hefty burden because of overexploitation, habitat degradation and invasive species, wild nurseries can provide an effective approach for in situ conservation of medicinal plants that are endemic, threatened, and in-demand. E.g. Periyar wildlife sanctuary, Kerala Bandipur wildlife sanctuary, Karnataka Dandeli wildlife sanctuary. C- Biosphere reserves: - They are areas of terrestrial and coastal ecosystems promoting solutions to reconcile the conservation of biodiversity with its sustainable use. Out of the 34 biodiversity rich spots in the world, three lies in India; they are the Western Ghats, Eastern Himalayas and Indo-Burma region. There are 18 biosphere reserves in India. These aim at securing the ecosystem by stopping irresponsible interference of humans with the ecosystem and also to conserve the endemic and endangered species.  Ex Situ conservation of medicinal plant: - Ex-situ conservation deals with the “off-site conservation” of the wild genetic resources in outside the natural habitat. It includes the collection, preservation and maintenance of certain genetic resources from wild. Ex-situ method of conservation is a complementary action to conserve the genetic diversity, thereby reducing pressure on wild environments and enhancing raw material availability.
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  A- Botanic gardens:- It is a garden dedicated to the collection, cultivation, preservation, and display of a wide range of plants labelled with their botanical names. It should set up seed banks for the medicinal plants native and cultivated in the country. Botanical Survey of India is actively engaged in the ex-situ conservation through its chain of Botanic gardens established in different regional circles. E.g. Government Botanical Gardens, Tamil Nadu, Garden of Medicinal Plants, West Bengal Empress Garden, Maharashtra B- Seed banks: - A seed bank stores seeds to preserves genetic diversity. Seed banks proposed a better way of storing the genetic diversity of many medicinal plant’s ex situ than through botanic gardens. Seed banks allow quick access to plant samples for the evaluation of their properties. The challenging tasks of seed banking are how to intro-duce again the plant species back into the wild and how to actively assist in the restoration of wild populations. C- Field Gene Banks: - Field gene banks conserve plants by using tools of biotechnology. These include: a- In vitro conservation b- In vitro propagation and re-introduction of plants to their natural habitats. c- Molecular masker technology Various In-vitro techniques have been developed to store vegetatively propagated seed producing species. These can be categorized as – A- Germplasm techniques: - i. Germplasm is a live information source for all the genes present in the respective plant, which can be conserved for long periods and regenerated whenever it is required in the future. ii. Germplasm conservation of vegetative propagated plants and forest species in life field gene banks require land and labour for annual or perennial replanting. iii. It further eliminates the need for long procedures during movement and ex-change of germplasms.
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  Methods Involved inthe in vitro Conservation of Germplasm: - 1) Cryopreservation: - i. In this technique the cells or tissues are preserved in a frozen state at very low temperatures using solid carbon dioxide (at –79°C), with low temperature deep freezers (at –80°C), using vapor nitrogen (at –150°C) and liquid nitrogen (at –196°C). ii. This technique includes four stages freezing, thawing, and reculture. This freezing temperature inactivates the cell and thus can be preserved for a longer time. iii. Any tissue from a plant can be used for cryopreservation, for example, meristems, embryos, endosperms, ovules, seeds, cultured plant cells, protoplasts. iv. To prevent the damage caused to the cells (by freezing or thawing) various compounds like dimethyl sulfoxide, glycerol, ethylene, propylene, sucrose, mannose, glucose, praline, acetamide, etc. are added during cryopreservation. These compounds are called cryoprotectants, which prevents the damage caused to cells by reducing the freezing point and super cooling point of water. 2) Cold storage: - i. This is a slow growth conservation method that conserves the germplasm at a low and nonfreezing temperature (1–9°C). The main advantage of this method over cryopreservation is that it slows down growth of the plant material at cold storage (1– 9°C) in contrast to complete stoppage during cryopreservation, hence it protects the plants against cryogenic injuries. ii. Moreover, this method is simple, cost effective, and yields germplasms with better survival rates. Many outstanding examples of cold storage have recently been reported, for example, virus-free strawberry plants could be preserved at 10°C for about 6 years and several grape plants have been stored for over 15 years by using cold storage at temperature around 9°C. 3) Low pressure and low oxygen storage: - i. In this method atmospheric pressure (below 50 mmHg reduces plant tissue growth) and oxygen concentration surrounded by plant material are reduced, which causes the reduced availability of O2, reduced production of CO2, and hence photosynthetic activity is reduced, which inhibits plant tissue growth and dimension.
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  ii. These conditionsmay lead to slow and reduced growth of the plant material, which assists in increasing the shelf-life of many fruits, vegetables, and flowers. iii. Therefore, conservation of germplasm by conventional methods has several limitations such as seed dormancy, short-lived seeds, seed-borne diseases, and high inputs of cost and labor. Disadvantages- i. Certain plants may not produce viable seeds. ii. Certain plant seeds deteriorate rapidly due to seed-borne pathogens. iii. Certain plant seeds are heterogenous and are not suitable for maintaining true to type genotypes. iv. Application of cryopreservation technology can circumvent the above problems B- Plant tissue culture techniques: - 1) Cell suspensions: a) Pre-treatment: The cell suspension is inoculated at high density into standard medium containing 6% mannitol and cultured under standard conditions. b) The suspension is harvested when the cell will be dividing rapidly and chilled on ice. c) Cryopreservation: A double strength cryoprotectants solution (1M dimethyl sulfoxide (DMSO) + 1M glycerol + 2M sucrose) was prepared and one volume of cryoprotectants solution is added to one volume of cell suspension and the mixture is incubated on ice for 1hr. d) The mixture is dispensed as 1 ml aliquots and the ampoules are cooled at 1℃ min-1 until they reach -35℃. e) Storage: The ampoules are stored in or over liquid nitrogen. f) Thawing: The ampoules are dropped into sterile water at about 40℃ with a ratio of 4 ampoules to 150 ml water. g) Regrowth: The cells in suspension are transferred to several layers of 5 cm filter paper on the surface of a 9 cm agar plate containing a growth medium and are incubated under standard conditions. The cells and upper layers of filter paper are then transferred to fresh medium, until after 5 – 6 days, the cells alone are transferred to agar medium.
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  2) Zygotic embryos: a)Pre-growth: The embryos are excised aseptically from the seeds then in an open petri dish are exposed to a sterile airflow in a laminar flow cabinet for 3h. b) Cryopreservation: The embryos contained in plastic ampoules are immersed in liquid nitrogen. c) Thawing: The plastic ampoules are transferred to a water bath at 37 – 38℃ then placed on moist sterile filter paper in petri dishes for 10 days. d) Regrowth: After 10 days in the absence of medium the embryos are added to a standard growth medium to stimulate growth into plants Zygotic embryos. 3) Adventitious buds: a) Pre-growth: Uniformed nodes (5 mm in length) containing an adventitious bud are removed from stem sections of plants. b) Nodes are placed on agar medium containing 0.7 M sucrose and incubated under standard conditions for two days then transferred to a nylon membrane contained in a dish. c) Cryopreservation: Nodes are transferred to plastic ampoules then immersed in liquid nitrogen and stored under liquid nitrogen. d) Thawing: Nodes are thawed in a water bath at 25℃. e) Regrowth: Because of their size, nodes can be transferred individually to a standard growth medium and the adventitious bud is stimulated to develop as a shoot. Advantages of tissue culture: - a) The production of exact copies of plants that produce particularly good flowers, fruits, or have other desirable traits. b) Quickly produce mature plants. c) The production of multiples of plants in the absence of seeds or necessary pollinators to produce seeds. d) The regeneration of whole plants from plant cells that have been genetically modified. e) The production of plants in sterile containers that allows them to be moved with greatly reduced chances of transmitting diseases, pests, and pathogens. f) The production of plants from seeds that otherwise have very low chances of germinating and growing, i.e.: orchids and nepenthes.
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  g) To cleanparticular plant of viral and other infections and to quickly multiply these plants as 'cleaned stock' for horticulture and agriculture. Application of Tissue Culture: - a) Species which are difficult to regenerate by conventional methods and the only way to save them from extinction is to propagate them by tissue culture. b) Species where population has decreased due to over exploitation and thus initial bulking of the stock can be taken up by tissue culture. c) Species which show lot of variability in terms of the active principles with medicinal properties. Tissue culture of selected clones will help in sustainable harvest and fetching better prices both in the domestic and international market. d) Trees with medicinal properties or elites can be identified based on their potential of yielding higher amount of active principle.