Abstract
At present we are passing through a global biological extinction due to various factors. Plants are one of the key constituents of the ecology. Human life is dependent on plants for fulfilling basic needs- food, shelter and medicine. We are losing tropical forests at a rate of 50 hectares per minute and, as a result, one plant species is becoming extinct every day on an average.
Flora of Indian subcontinent is very rich in diversity and endemism. India has an estimated 16,000 vascular plants; 5,000 endemic species distributed into different biogeographic zones. These zones have a unique diversity climatically, geographically and biologically which are the habitat of tropical evergreen and alpine-arctic vegetation. But paradoxically, 10-15% of the Indian flowering plants are under various degrees of threat. Nevertheless, 25% will become rare by the turn of the century unless proper conservation measures are taken.
Botanic Gardens serve as a repository of germplasm collection and ex-situ conservation of plants especially rare and endangered ones of indigenous and exotic origin. Each Botanic Garden should play a significant role in preserving genetic diversity and to ensure sustainable utilization of the species as spelt out by IUCN, IABG, and BGCI. Cumulative efforts are to be initiated for providing required microclimate to the individual plant species for their conservation. Surveys should be carried out for ascertaining the population of the threatened species in nature from time to time. Ex-situ conservation of the rare and endangered species in the Botanic Garden, their multiplication and, ultimately, rehabilitation in the nature would be the most effective strategy for the conservation of the plant genetic diversity in the new millennium.
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