Seed banks:
- One of the most efficient methods of ex-situ conservation for sexually reproducing plants is the storage of conservation material in form of seeds.
- Every kind of seed has a distinct genetic makeup, thus consists a wide variety of genetic diversity.
- Seeds being small in size take up small space.
- At practical level, seed bank depends upon secure power supplies, requirement for careful monitoring, and periodical testing of seed viability.
- Seeds of orthodox types which has been previously dried to about 5-8% moisture content can be conserved for very long periods at temperatures below zero.
- The longevity varies from taxon to taxon, viability of seeds in medium-term storage (0°-5°C) can be 5-25 years whereas long term storage (-10°C to -20°C) can provide viability perhaps for a hundred years.
- Many tropical species produce seeds that possess no natural dormancy and die quickly if not allowed to germinate immediately. These are termed as recalcitrant seeds.
- Recalcitrant seeds are easily killed by the usual techniques of storing under reduced temperature and humidity.
- It is estimated that 50,000 plant species produce seeds that do not survive at low temperature and/or dehydration.
- Species with recalcitrant seeds and those who do not readily produce seeds are required to be maintained ex-situ as growing plants in field gene banks or as living collections.
- Recalcitrant fruits and seeds like Cocos nucifera (Coconut palm), Bertholetica excelsa (Brazil nut) are stored directly on mother trees in Sacred Grooves, Forest and Biosphere Reserves, National parks and in the Arboretums and Botanic gardens.
- There are Germplasm Storage Centers throughout the world where orthodox seeds are stored.
- The gene banks are closely related to plant collection activities either for taxonomic studies or breeding.
- The Consultative Group on International Agricultural Research (CGIAR) was established on 1971 to support a global network of gene banks which are located at 13 international agricultural research centers.
- The International Board for Plant Genetic Resources (IBPGR) and Crop Genetic Resource Centers have developed about 60 gene banks in the last 20 years with long- or medium- term storage facilities of crop plants.
- Currently only relatives of wheat (60 spp. or 75-80% of the total), potato (40 spp. or 70% of the total), tomato (10 spp or 90% of the total), and to limited extent, maize (15 spp. or 50% of the total) have been extensively collected and preserved in seed banks.
- Germplasm of only few traditional cultivars and wild relatives of crops has been collected and preserved by various Nepalese institutions, the few examples consists of rice, wheat, buckwheat, and maize in National Agricultural Research Council (NARC), buckwheat in Research Center for Applied Science and Technology (RECAST), many wild germplasm in National Herbarium and Royal Botanical Garden, Amaranth in Tribhuvan University (TU) while most wild relatives of crops still thrive only in the wild.
- The security of germplasm must be assured by making not only the germplasm available but also providing adequate information for a conservation effort to be sustainable.
Botanical gardens:
- According to Botanical Gardens Conservation International (BGCI), an independent UK based organization, Botanical gardens can be defined as public as public gardens which maintain collections of live plants mainly for study, for scientific research conservation or education.
- Botanical gardens fulfill an important role in preserving the world’s plant diversity by:
- Growing large collections of endangered plants and holding them safely in cultivation or seed banks in case wild populations are destroyed
- Reintroducing plants to the wild as a part of species recovery process
- Undertaking botanical research to document and record the plants of the world, region or country and their characteristics, for example, herbaria contain millions pf specimens as a permanent reference on plant diversity
- Promoting environmental awareness among the public through their education work
- Providing expertise and training to grow plants
- Helping to conserve natural vegetation by maintaining nature reserves and working with others to study, monitor and conserve plants and their ecology in the wild.
- In global perspectives, botanic gardens are an essential network of botanical resource centers for environmental conservation.
- Botanic gardens have become a place of multiple significance both for the general public as well as scientific community.
- Rhododendrons in Royal Botanic Garden, Edinburgh, Chrysanthemums in Missouri Botanical Garden, USA and Botanical Garden, Kyoto, Tulips in Leyden University Garden, The Netherlands, different kinds of flowering shrubs in Royal botanic Gardens, Kew and Arnold Arboretum, USA are quite a few places that represent fascinating examples of collection of indigenous as well as exotic plants.
- Above all immediate role of botanical gardens in the ex-situ conservation of rare and endangered species lies in research and education rather than in conservation.
- In nature, plants commonly exist in small populations. Example includes many rare endemic which occur in isolated areas where, in general, conservation priorities are low.
- It is quite often that too little is known of the ecology of many plant species.
- Further, destruction of natural habitats is taking place at an alarming rate.
- Ex-situ conservation in botanic garden serves the purpose of buffer against extinction of rare and endangered species as well as promote interdisciplinary research and instruction.
- Botanic Gardens Conservation International estimates that there are about 1600 botanic gardens in the world.
- They grow tens of thousands of plant species between them, probably as much as a quarter of all the world’s flowering plants and fens are in their collections.
- There are few botanic gardens in Nepal which are poorly funded and inadequately developed, thus, they have not been able to play significant role in conservation and research. Some of notable botanic gardens are Botanical Garden, Godavari and botanic garden of Tribhuvan University, Kirtipur.