Sreekandan Nair, GJyothilekshmi, LKAU2019-06-202019-06-202001http://krishikosh.egranth.ac.in/handle/1/5810109297PGA study on 'Biodiversity of medicinal plants in Vellayani' was carried out in and around Vellayani lake of Thiruvananthapuram district, Kerala. The objectives of the study were to identify the medicinal plants from among the existing natural flora, to study the growth behaviour of selected medicinal plants and to assess the pharmacologically active constituents of selected medicinal plants. A total of 80 sampling units were taken usmg stratified random sampling technique, the strata being dry land, garden land, paddy field and lake area. The medicinal plants in dry land, garden land and paddy field were identified and quantified by random sampling technique using 1.0 m2 frame. In the lake area as it was difficult to use the frame the plants were collected randomly giving sufficient representation. A total of 135 plant species were identified in the four different strata belonging to 120 genera and 57 families. None of the plants were endemic. There were 118 indigenous and 17 exotic or naturalized plants. Ten important medicinal plant species were selected for detailed study and their' growth behaviour was monitored for one year. They were Andrographis panieulata, Cyclea peltata, Desmodium velutinum, Eclipta alba, Gloriosa superba, Hemidesmus indieus, Phyllanthus amarus, Scoparia duleis, Sida rhombi/alia and Solanum indieum. Emilia sonchifolia dominated in dry land area with high relative density and relative frequency. Centella asiatica was the dominating species in garden land and paddy field with high relative density. Limnophila repens was the dominant species in lake area. Most frequently occurring species in dry land was Emilia sonchifolia and in garden land Scoparia dulcis and Vernonia cinerea. Centella asiatica and Eclipta alba occurred more frequently in paddy field, where as in lake area Hydrilla verticellata occurred more frequently. The rare species in dry land were Abrus precatorius, Blepharis medaraspatensis, Carissa congesta and Rauvolfia serpentina. In garden land Acalypha indica, Capparis brevispina, Cayratia pedata, Catharanthus roseus var. alba were found to be rare. In paddy field Borraria alata, Coldenia procumbens and Portulaca oleraceae were found to be the rare species. Diplocyclos palmatus was the rare species in lake area. Dry land and garden land were found to be the most similar strata with more number of species in common. Dry land and lake area were found to be the most dissimilar strata in vegetation pair wise analysis. Lake area was found to have higher concentration of dominance as expressed by Simpson's index. Shannon's index was maximum in dry land area. Abundant species occurs more in dry land area. In dry land almost all species had equal number of individuals since Evenness index was maximum. Growth characters like plant height, plant spread, height of the first branch, number of leaves, number of roots, root length were found to increase from pre-flowering to seed set stage. These characters were found to be high in garden land compared to other strata in most of the species. The fresh and dry weight of officinal part was more in garden land condition in most of the species. In the chemical analysis it was found that in Limnophila repens there was no similar chemical constituents as that of Bacopa monnieri (brahmi). There was no bacoside content in Limnophila repens, which is present in Bacopa monnieri. So Limnophila repens cannot be used as a substitute for brahrni. The andrographolide content in Andrographis paniculata was found to be slightly higher in dry land compared to garden land. The andrographolide content was higher in dry land area because of the water stress condition in dry land. The results of this study will be helpful in evolving suitable strategies for sustainable utilization of medicinal and aromatic plants, occumng as indigenous and naturalized in and around the Vellayani lake. Such an effort would also help to conserve many of the weed species which have very high medicinal values.ennullThesis