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    Biodiversity conservation: in situ and ex situ.
    By Ashwani Kumar | October 20th 2012 01:37 AM | Print | E-mail | Track Comments
    About Ashwani

    Professor Emeritus ,Former Head of the Department of Botany, and Director Life Sciences, University of Rajasthan, Jaipur. 302004, India At present...

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    I had a chance to witness plant conservation sites in Sweden, Japan  Germany and India. Almost all the plant species are conserved in cold storage , in liquid nitrogen, and in different methods of storage so that if mankind looses all plants on earth in the event of some circumstances of floods or man made devastations the life can be started again. Although we don't envisage a threat of nuclear war now but  it was so much in the air just 4 decades ago  that plant storage facilities were made to withstand even atomic attacks. In that event all life has to be started afresh and it will need contamination free planting material. Though we don't envisage accidents but any biodiversity conservation method should take in to account all eventualities. Biotechnology and gene preservation techniques have made things lot easier but are we immune to all possibilities and is our storage in situ and ex situ well guarded ? 

    Basically botanical gardens and herbaria were main source of plant collections and I very much appreciate Botanical Gardens of Kew England, Botanical Garden of Giessen one of the oldest along with Botanical garden of Frankfurt  and in Chicago , and many in USA. 

    However now its time to have ex situ conservations globally with an object of preserving live materials and plant tissue culture plays an important part in it. 

     100,000 plants representing 1/3rd of plant species are threatened.

      Since the 1970s large number of land races and wild relatives are   sampled and stored ex situ

     Now,about 6 million samples are held in national, regional,   international and private genebank collections

     In situ :Conservation in ‘normal’ habitat 

    –       rain forests, gardens, farms

    Ex Situ conservation: in man made environment and storage conditions :

    –       Field collection, Botanical gardens

    –       Seed collections

    –       In vitro collection

    •       Normal growth conservation 

    •       Slow growth conservation by lowering temperature , Oxygen and water contents 

    '•       Cryopreservation(-196°C)

    –       Storage of living tissues atultra-low temperatures (-196°C)

    •       Use

    –       Conservation of plant germplasm

    •       Vegetativelypropagated species (root and tubers, ornamental, fruit trees)

    •       Recalcitrantseed species (Howea, coconut, coffee)

    –       Conservation of tissue with specificcharacteristics

    •       Medicinaland alcohol producing cell lines

    •       Geneticallytransformed tissues

    •       Transformation/Mutagenesiscompetent tissues (ECSs)

    –       Eradication of viruses (Banana,Plum)

    –       Conservation of plant pathogens(fungi, nematodes)

    –       Cryopreservation procedures are nowavailable for about 150-200 different plant species

    –        But for each species and tissue type, thecryopreservation protocol needs to be empirically adapted in function oftheir

    •        natural freezing resistance

    •        explant size and type

    •        water content

    –        Most of the work on cryopreservation of plantshas been performed in the framework of academic studies and involvesonly one or a few genotypes. Only few plant germplasm collections stored inliquid nitrogen currently exist (with a relatively limited amount ofaccessions).