Necessities of Plant Biodiversity Conservation and Utilization

Patu Khate Zeliang
Krishi Vigyan Kendra, Jalukie, Peren  

Introduction: Plants are the primary source of energy in the biosphere and it is the basis of all life. Plants are one of the most important sources of food, fuel and medicines.  Application of plants to health care perhaps dates back to prehistoric period. There are several thousand of drug yielding plants in the whole world and the science concerning them is known as ‘pharmacognosy’. (Kush, 1998). There are about 250,000 species of flowering plants in the world. The size of the resource is almost certainly very much greater, given the poorly documented state. In the first ever comprehensive publication, detailing the World’s threatened plants by Walter and Gillett (1998)  they listed 34,000 species or12.5% of the World’s flora as facing extinction. Many endangered species have a current or potential economic value either in themselves or as doners of genes. Due to the dramatic increase in exports of medicinal plants and the worldwide interest in traditional health systems, most of these plants are taken from the wild. Hundreds of species are now threatened with extinction because of over harvesting, destructive collection techniques and conversion of habitats to crop-based agriculture.  

Needs of Biodiversity Conservation: There are so many reasons for conserving biodiversity as explained below:

1. Maintenance of a stable Environment/Ecology: The ecosystem processes, particularly the cycling of matter and the flow of energy are major determinants of the quality of the enviroment. The oxygen and water contents of the atmosphere are related to the photosynthetic activity of green plants (Rae et al, 1999). Soil fertility relies on the breakdown and cycling of organic matter by microorganisms, many of which are plants. If these are eliminated, the organic matter accumulates, locking up vital nutrients. Climate change caused by increased carbon dioxide, reduced ozone or atmospheric pollutants may alter the composition of forest and savannas, affecting the natural equilibrium.
2. Scientific:The scientific case for protecting plants and habitats is that they form part of our natural heritage from which new knowledge may be obtained. They may contain chemicals in different combination. They are also important indicators of environmental change. Plants hold all sorts of additional data that might be useful to science (Rae et al, 1999).
3. Aesthetic and Cultural Needs:Plants beautify our surroundings. Even from the earliest civilization gardens have been recorded. Planner and architect in the city streets and parks use plants. They improve the environment visually and also provide shade, trap dust, reduce noise and slow winds. In some cases plants have been deployed to such great effect that the results become works of art.
4. Economic Needs: Thousands of plants contain useful chemicals. However many are almost unknown outside the regions where they are gathered. It is estimated that at least 25% of drugs used in western medicine are derived from plants and approximately 120 pure chemical substances extracted from plants are used in medicine throughout the world. Some 80% of the people in developing countries rely on traditional medicine for primary health care and 85% of these medicines involve the use of plant extracts (Farnsworth, 1988). Plants yield pesticides, latexes, cork, gums, resins, waxes, dyes, wood and essential oils. Many more uses remain to be discovered. At least 75,000 plants are edible and about 3,000 of these have been used for human food. Apart from these, other species are likely to be of commercial value because of the opportunity they offord for improving the genetic constitution of existing crops (Fincham and Ravetz, 1991). The wild relatives of crop species may hold the genes required to confer such attributes as disease, higher yield or drought resistance. With the advance of genetic engineering the requirement for novel genetic information has increased dramatically. While genetic engineers have the capacity to synthesize new genes from DNA, it is probable that genetic diversity from wild species will remain highly important. (Fincham and Ravetz, 1991).
5. Moral arguments:The moral argument for conserving species also forms an important basis. Norton (1987) described how three kinds of values can be distinguished; demand, intrinsic and transformative. Demand values occur when an object such as a species provides satisfaction for some felt preference. Intrinsic value recognizes that something has a value to humanity. Thus far from exploiting some species to the verge of extinction, humanity has a responsibility for their stewardship. Transformative value involves a change in a person’s previous set of felt preferences in relation to constitutional issues.

  Approaches towards Biodiversity Conservation: There are two basic approaches to conservation of species

1. In-situ: This involves preservation of entire habitats rich in biodiversity in their pristine or natural beauty. They include national parks, biosphere reserves, sanctuaries and sacred grooves.
2. Ex-situ: Focuses on collection and storage of seed, and involves removal of either whole plants or their reproductive parts for conservation in an alien environment,
3. a) Whole plants- in Botanical gardens, arboreta, herbal garden.
4. b) Reproductive parts- in seed banks, in-vitro banks, cryobanks, DNA banks etc.

In cases where seeds do not set or is sterile, unsuitable for storage, through biotechnology, the pollen or plants obtained from elite genotypes, in-vitro raised tissues or organs can be preserved. Medium term preservation of in-vitro tissue is brought about by altering the growth rate through the modification of the medium, induction of cultures at low temperatures or both (Touchel et al 1999). For long-term preservation, cryogenic storage is the method of choice where biological materials are stored at ultra low temperature using Liquid Nitrogen (LN) at -(minus)-190°C. At this temperature all metabolic activities in the tissues have ceased and tissues can be stored in LN indefinitely without loss of viability. Cryopreservation procedures have been shown to be species specific and further studies will increase the applicability of the procedure to many threatened species from around the world (Touchel et al 1999). The Department of Biotechnology has established three National Gene Banks (NGBs) dedicated to medicinal and aromatic plants at-Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow, National Bureau of Plant Genetic Resource (NBPGR), New Delhi, Tropical Botanical Garden and Research Institute (TBGRI), Thiruvananthapuram.  

Research on Conservation of Medicinal Plants: Though research in organic chemistry is gaining strength, plants still remain the most valued and important source of chemicals and compounds of medicinal importance (Rawal, 1993). Some emerging medicinal plants in world Pharmaceutical industry:  

1. May Apple (Podophyllum peltatum):

Podophyllotoxin is a ‘Drug of choice’ for brain tumour and Hodgkin’s disease. The resin podophyllin from the rhizome was also used for venereal warts (condyloma acuminatum). The rhizome and roots contain 2 to 8 % resin in 4 to 6 years old plants. Its Indian ally, P.hexandrum (Himalayan mayapple) is superior in resin content (6-12%) with higher podophyllotoxin content (Gupta 1998). It grows about 5cm long and 1.2 cm thick with 5-7cm long root system in 5-6 years. Over exploitation has made it an endangered species in India. Tissue Culture may provide scope for raising new plantlets.  

2. Yew (Taxus brevifolia)-

Yew is having an anti- cancer compound taxol, which is produced from the growing shoot and bark of the tree. Its foliage contains 10-de-acetyl becatine, becatine and cephalomannine, which are, converted into several taxol derivatives in industry. It occurs in very small quantities (100 ppm). Trees can provide 5-20 pounds of bark. It would take 2000 – 4000 trees to provide 1 kg of Taxol, enough for clinical trials on 500-1000 people (Duke 1997). Yew also grows in Meghalaya, Manipur and Nagaland.  

3. Ginghasu/sweet wormwood (Artemisis annus Linn)-

A small herbaceous perennial with dissected aromatic leaves and grows a metre tall. Artemisinin is a non- volatile sesquiterpine lactone isolated from A.annus at flowering stage occurring at about 0.06 to 0.020 percent. It has been found to be effective against the malarial parasite (P.falsiparam) causing cerebral malaria. (Gupta 1998). The CIMAP, Lucknow, has developed a new culture ‘asha’ through mass selection, which produces 2.9 t/ha of herbage at bloom, containing 0.11 percent artemisinin.  

4. Temple Tree (Ginkgo biloba Linn)-

It bears a cluster of fan shaped leaves. The foliage of this tree contains ginkolides A, B, C and flavonoids. Ginkgolide A- is a novel diaterpene, which increases blood flow in patients suffering from cerebro-vascular disorder (ischaemia) and is also given in treatment of Parkinson’s disease. Ginkgolide B- is platelet-activating factor (PAF) affecting human polymorpho nuclear granulocytes. The leaves also contain procyanidin flavonoid mixture, which produce vasodilator activity.  

5. Guggal/Indian Bdellium Tree (Commiphora mukul):

A slow growing shrub reaching 3.5m in 8 to 10 years and is highly branched and spinescent inhabiting parts of Saurashtra and the west Rajasthan desert. Gum oleoresin exudates from woody stem of Guggal or the Indian bdellium tree contain Z+E gugglusterones, which are highly potent in treatment of arteriosis. It reduces internal inflammation and its antiarthretic property is comparable to hydrocortisone, but with negligible side effect.  

6. Prickly thysel (Silybum marainum Gaertn.)-

The plant grows upto 1.2m high. The flowers bloom during March – April and the seeds ripen in early summer.silymarin and silydianum flavonoids isolated from seeds of the prickly thysel have shown significant antiheptaoxic activity, which are effective in preventing galactosamine produced cell lesions, homolysis and lipid peroxidation induced by phenyl hydrazine.  

7. Wild yam (Dioscorea villosa)-

It is well endowed with diogenin. Apart from soybean and maxican yam all major expansive hormones could be synthesized from the starter material, diogenin. It is used as a contraceptic, relief of pain during childbirth (Moerman’s 1986). The ‘carrion flower’ is used for afterbirth, backache, body odor, boils, constipation, cramps, dysmenorrhea, gastrosis, hoarseness, nephrosis, pain and pulmonesis. The yam contains not only sapogenins but also 100-1000ppms sterols, mostly beta-sitosterol (Spiller 1996). About 60 mg a day of sitosterol is reportedly efficacious in the old man’s prostrate ailment, benign prostatic hyperplasia or hypertrophy (BPH).  

8. Periwinkle (Catharanthus roseus):

The vinca alkaloids – vincristine and vinblastine are major chemotherapeutic agents in the treatment of leukaemias and lymphomas. They are derived from the leaves of the Madagascar periwinkle (Catharanthus roseus).  

9. Ginseng (Panax ginseng):

It is the most famous herb of all, having a wide range of health benefits and is more useful for maintaining good health. It helps the body adapt to stress, fatigue and cold. The ginsenosides which produces a sedative effect when the body requires sleep are similar in structure to the body’s own stress hormone. Ginseng also increases immune function and resistance to infection and improves liver function. (Nagaland Horticulture Handbook, 2000).   Some examples of drug plants endangered in India are, Chlophytum borivillianum (Safed musli), Coptis teeta (Mihmi teetha), Coscinium fenestratum (Jeevanthi),Dioscorea deltoidea (steroidal yam), Gentiana kurro (Indian gentian),Inula recemosa (Pushkar mool), Nardostachys grandiflora (Jatamansi), Podophyllum hexandrum (Bankakri), Picrorhiza kurroa (kutki),Rauvolfia serpentina (Sarpagandha), Swertia chirata (Chirayta), Taxus baccata (Talispatra).  

5. Scope of Biodiversity Conservation in the context of NEH Region:

North Eastern Region of India consisting of the eight states, viz., Assam, Sikkim, Meghalaya, Nagaland, Mizoram, Manipur, Tripura and Arunachal Pradesh have tremendous biodiversity. It is endowed with cool favorable climate and optimum rainfall (1200-2800 mm per year). Despite the rich heritage of knowledge on the use of plant drugs, little attention has been paid to grow them as field crops in the country particularly in the NEH region of India. Medicinal plants are the local heritage with global importance and play an important role in the lives of rural people particularly in remote parts of developing countries with few health facilities. The NEH region is also mainly inhabited by Tribal populations who possess lots of indigenous medicines prepared from locally found plants, but of all the reasons to consider conservation, none is more important to individual farmers than the economic development. The cultivation of medicinal plants and crops can be an avenue for upliftment of the hill farmers.  

Strategy for Conservation of Biodiversity Some basic strategies for efficient and effective conservation program must include the following

• Agricultural support agencies should strengthen extension efforts to farmers
• Research institutions need to improve basic knowledge about cultivation practices and dissemination of plant species
• Conservation agencies and NGOs should promote conservation of vulnerable species at the grass roots level
• Community organizations need to adopt sustainable collection and management practices on public lands
• Profitable private enterprises for processing, transporting and marketing must be developed
• Government institutions need to be strengthened to regulate these important resources and at the same time foster their sustainable development and conservation.

  Conclusion: The potential of plant genetic variability for favorable characteristics from primitive cultivars and relatives of various crops are considered to be a storehouse of valuable genes. The distribution of medicinal and aromatic plants in forest areas are found throughout the country. Since conservation technologies are at the heart of sustainable agriculture providing dynamic solution to problems encountered in increasing food production, without damaging the ecosystem or depleting natural resources for future generations, the conservation strategies for medicinal plants have to take into consideration the survival of the species on one hand and the sustained supply of raw material on the other (Raina et al,2011). Long term objectives of conservation and sustainable use can be achieved by conservation through cultivation, optimizing yield parameters for increased productivity and avoiding destructive harvesting.