In-vitro Conservation of Phytochemically Enriched Orchids of Indian Western Himalayas

Orchids are identified for their beautiful ornamental flowers. These flowers exceptionally possess long extended vase life. Besides being floriculturally significant, they also find their description in the ancient Ayurvedic system of medicine for their therapeutic uses. These monocot herbaceous plants possess diverse bioactive chemical compounds such as terpenes, alkaloids, etc. that are responsible for their therapeutic value properties. The orchids are collected stealthily from their natural habitats indiscriminately and have become rare in the wild and their populations can be saved through in vitro conservation techniques. The present communication conveys conservation techniques used for saving orchid species from getting extinct.


INTRODUCTION
The vast geographic expense of India, harbours a broad range of plant species of diverse habits and habitats. Taxonomically, the orchidaceae, is highly evolved family of monocotyledons, encasing 25,000-35,000 species in nearly 800 genera [1]. The orchid blooms are extremely beautiful and continue fascinating scientists and a layman globally. These natural marvels exhibit an array of mesmerizing shapes, sizes, and colours. In Indian system of medicine, the orchids also find mention for their curative properties [2].
In Indian system of medicine, an Ayurvedic formulation, 'Ashtavarga', which is known to be a revitalizing herbal medicine consists of 8 herbs

Review Article
and out of these, four herbs to family orchidaceae namely Habenaria intermedia (Riddhi), Habenaria edgeworthii (Kakoli), Dendrobium macrae, and Malaxis wallichii (jivak) [1,3]. A sizeable number of phytochemicals and drugs are found in orchids. A variety of orchid species are known to possess glucoside and alkaloid compounds (Table 1).

ORCHIDS OF WESTERN HIMALAYA (SHIMLA HILLS)
The Indian Western Himalaya is expanded through tropical plains from alpine to arctic climates within an altitudinal range of 300-8611m. It receives an annual rainfall of almost 600-1800 mm. The region of Indian western Himalaya is one of the major hotspot of biodiversity [5].

CONSERVATION STATUS
Therapeutic orchids are enriched with a large number of secondary metabolites such as glycosides, alkaloids, and flavonoids. These orchid herbs are used widely in the Indian ayurvedic medicinal system. Orchid species were collected from their foster homes unabatedly. This over-exploitation exceeds their natural regeneration. As a result, the entire orchidaceae family is placed under rare, threatened, and endangered category. It is tabulated in the appendix I & II of checklist prepared by IUCN [22]. -Normally, the orchids require an amiable atmosphere to flourish in their territorial habitats. Their extinction could also pose a deep influence on the ecological system. Consolidative scientific methodologies are required for their ex situ and in situ conservation. There is a need of continuous efforts to eco-restore these rare species through biotechnological practices. In vitro, techniques have emerged as a viable system to save and multiply their germplasm from getting extinct in nature.

STRATEGY FOR CONSERVATION OF BIODIVERSITY
Conservation term is a combination of 'preservation and utilization'. In broader sense, conservation refers in saving wild populations of plant species in their natural environment. Biodiversity of a species can be conserved by adopting scientific approaches as well as participation of the society. Principally, the conservation of plant genetic diversity is achieved by following measures:-1. In-situ conservation 2. Ex-situ conservation

In-situ Conservation
In situ conservation deals especially with saving plant species in their natural environment. A particular species which is saved in its wild habitat where it thrives naturally refers to in situ conservation. It includes wild-life sanctuaries, sacred grooves, national parks, sacred sites, biosphere reserves, cultural landscapes, protected forest areas and gene banks. In natural environment, the diversity in plant species can be conserved on a long-term basis at genus, species, and ecosystem level.
Many conservation approaches are adopted to save naturally growing diverse orchids by establishing National Orchid and Biodiversity Parks, biosphere reserves, orchid sanctuaries, etc.

Ex-Situ Conservation
Ex-situ conservation is a measure that is external to the natural habitat. Mainly, it is established in the botanical gardens many institutes exclusively engaged in botany such as Botanical Survey of India, several universities, R&D research centres, national parks, and farmer's field, and also done through in vitro seed banks, gene banks, and pollen banks, DNA libraries, and through advanced techniques involving cryopreservation and various plant tissue culture techniques. In vitro asymbiotic seed germination-The method of germinating orchid seeds in vitro in a nutrientenriched medium assists with conserving and propagating orchid species [23]. The technique developed by Knudson established asymbiotic seed germination protocols. This protocol helped in evading the requirement of mycorrhiza in in vitro germination of orchid seeds. This technique also assists in achieving an optimum percentage, besides reducing the time lapse occurring in between pollination process and seed sowing [24]. The asymbiotic seed germination helps in achieving a better percentage of germination from immature seeds, than from mature seeds, as the immature seeds are always in their physiologically active state and are devoid of any kind of dormancy or inhibitory factors [25]. The asymbiotic seed germination technique has been successfully used in a large variety of orchid species of diverse habit and habitats [26][27][28][29][30][31][32][33][34][35].

CONCLUSION
The orchid species are valuable herbaceous monocot plant species, which synthesise a variety of biochemical compounds. These herbs find their mention in the ancient ayurvedic system for their curative properties. This indigenous knowledge, if blended together with modern research activities has the capacity to make new drug formulations for the benefit of mankind in today's times to cure chronic diseases.

CONSENT
It is not applicable.

ETHICAL APPROVAL
It is not applicable.