Traditional Knowledge and Commercial Cultivation of Medicinal Plants in Natore Oushodi Gram and in Vitro Conservation of Some Selected Species

Abstract

Total area of Natore district is 1896.05 sq km, is bounded by Naogaon and Bogra districts on the north, Pabna and Kushtia districts on the south, Pabna and Sirajganj districts on the east, Rajshahi district on the west. The study area was Laxmipur-Kholabaria union of Natore sador upozilla under Natore district. Owing to the unique practices of commercial cultivation of medicinal plants made by the farmers, instead of agricultural crops, the area has been designated as the “Oushodi Gram” meaning the villages of medicine. Natore Oushodi Gram has become a resource centre for herbal medicine and imparting training to the new farmers motivated for the commercial cultivation of medicinal plants in the village area. The livelihood of the local people of this area depends mostly on agriculture. They are poor community and the natural and cultivated medicinal plants became the earning source of their livelihood and also provide a major part of the medicines for treatment of different diseases. The traditional knowledge related to the use of medicinal plants is important to the context of exploitation of plant genetic resources and the local herbalist commonly known as kobiraj/herbal doctors have this kind of knowledge, which they inherited from their previous generation. The present study was undertaken to make a survey on traditional knowledge of medicinal plants in the area and cultivation of medicinal plants in homestead, agricultural lands and other fallow lands which collectively generated different avenues of income generation over the area. Field survey was conducted during “October 2010 to September 2011” covering the seasons; summer, winter and rain. Under this study survey was made in eight villages; kholabaria, kanthalbaria, borobaria, toltolia para, khamar para, gazipur, ibrahimpur and laxmipur in Natore Oushodi Gram. Socioeconomic and ethnobotanical information were collected using a format of questionnaire interviews with 160 local respondents (medicinal plant farmer, kobiraj/herbal doctors, hawker, whole sale dealer, nursery owner). All interviewees were male except two were female. Results indicated that majority of the respondents were of middle age (43%), under the age between 34-49 yrs. In terms of literacy, 17 percent of the respondents had no formal education; on the other hand 83 percent respondents had formal education in different levels. The respondents were selected from the local people in any way involved in the activity of medicinal plants and the results revealed that out of 160 respondents 72 percent were medicinal plant producer, 11 percent herbal doctor, 10 percent hawker, 3 percent nursery owner and 4 percent wholesaler. One hundred and twenty medicinal plant species belonging to 51 families and 111 genera were identified and their ethnobotanical uses were studied. The predominating families were Fabaceae, Lamiaceae, Zingiberaceae, Euphorbiaceae, Acanthaceae, Compositae, Solanaceae, Liliaceae, Malvaceae, Apocynaceae, Combretaceae and Rutaceae. Among all the families Fabaceae contained the highest number of plant species with medicinal properties. Considering the habit of the medicinal plants, herbs were more prevalent than shrubs, trees, climbers and epiphytes. Seventy one diseases were addressed to be treated with these 120 medicinal plants. Fever, cough, asthma, sexual disease, diabetes, skin disease, rheumatism, weakness, stomachache were noted as the most common diseases being treated by these plant species. Leaves were recognized as the most frequently used part of the medicinal plants studied under this investigation and in most cases plants parts were used in the form of juice. In Natore Oushodi Gram cultivation of medicinal plants has appeared as the new venture of commercial cultivation for subsistence living. Now a day’s many marginal and poor farmers were found to be fully dependent on the income of medicinal plants, which the traditional agriculture fails to compete. Another potential investigation of the present study was to establish protocol for in vitro propagation of some important medicinal plant species. In vitro study was done in seven species; Asparagus racemosus, Curcuma amada, Ipomoea mauritiana, Mentha arvensis, Paederia foetida, Rauwolfia serpentina and Smilax zeylanica. Node, axillary bud, shoot tip, internode and leaf segments were used as explants under the tissue culture study. MS basal medium supplemented with different concentrations and combinations of auxins and cytokinins were used for the induction of direct and indirect organogenesis and rooting. Among the five types of explants, nodal segments were responded better but sometimes axillary bud responded also better than shoot tip, internode and leaf segments, and BAP was proved to be the most effective cytokinin than that of Kn in artificial culture of these medicinal plants. Under in vitro study, MS medium supplemented with 2.0 mg/l BAP + 0.5 mg/l NAA was determined as the best media formulation for the direct organogenesis in nodal explant of Asparagus racemosus. Callus induction was maximum in internode explants on MS + 0.5 mg/l BAP + 1.0 mg/l Kn + 1.0 mg/l 2,4-D. Formation of adventitious shoots from leaf derived callus was highest in MS + 1.0 mg/l BAP + 0.2 mg/l NAA. Rooting was best in half strength MS + 2.0 mg/l Kn + 0.5 mg/l NAA. In Curcuma amada, shoot tip explants were proved best for the induction of direct organogenesis. Direct organogenesis was highest in 0.5 mg/l BAP + 0.5 mg/l NAA. Microrhizome induction was best in 1.0 mg/l BAP + 0.2 mg/l NAA of shoot tip explant. Rooting was best in half strength MS + 0.5 mg/l IBA. In case of Ipomoea mauritiana, nodal segments were proved best for the induction of direct organogenesis. Direct organogenesis was highest in 1.0 mg/l BAP + 0.5 mg/l IAA. Callus induction was best in leaf explants on 1.0 mg/l 2,4-D + 2.0 mg/l BAP. Maximum (40%) shoot bud regeneration was obtained from internode derived callus in 1.0 mg/l BAP + 0.5 mg/l IAA. Rooting was best in half strength MS + 0.2 mg/l IBA. In case of Mentha arvensis, nodal segments also proved best performer for the induction of direct organogenesis. Direct organogenesis was highest in 1.0 mg/l BAP + 0.2 mg/l NAA. Highest number of shoot multiplication and elongation was observed in MS + 0.5 mg/l GA3. Callus induction was best in internode explants on 2.0 mg/l BAP +1.0 mg/l 2,4-D. Maximum (65%) shoot bud regeneration was obtained from leaf derived callus in 2.0 mg/l BAP + 1.0 mg/l Kn + 0.2 mg/l NAA. Rooting was best in half strength MS + 1.0 mg/l NAA. In Paederia foetida, for direct organogenesis nodal segment perform best and the result was highest in 1.0 mg/l BAP + 0.5 mg/l IAA. Callus induction was best in internode explants on 2.5 mg/l 2,4-D + 0.5 mg/l IBA. Maximum (85%) shoot bud regeneration was obtained from internode derived callus in 1.0 mg/l BAP + 1.0 mg/l IAA. Rooting was best in half strength MS + 0.2 mg/l IBA. Direct organogenesis in Rauwolfia serpentina was highest in nodal explants on 1.5 mg/l BAP + 0.2 mg/l NAA. Callus induction was best in internode explants on 2.5 mg/l 2, 4-D + 0.5 mg/l BAP. Rooting was best in half strength MS + 0.2 mg/l IBA + 0.2 mg/l NAA. And in Smilax zeylanica, direct organogenesis was highest in nodal explants on 1.5 mg/l Kn + 0.5 mg/l L-glutamine. Rooting was best in half strength MS + 1.0 mg/l IBA. Another potential avenue of this present investigation was to establish protocol for in vitro conservation of some important medicinal plant species by artificial seed production. Attempt was taken to produce artificial seed by encapsulating the shoot tip and nodal segments of plants. For germination of artificial seeds , encapsulated shoot tips (synthetic seed) and encapsulated nodal segments (synthetic seed) were cultured on MS basal media containing different concentrations and combinations of BAP, Kn and NAA used to induce shoot proliferation. In Mentha arvensis the highest 80% shoot formation was observed in MS medium containing 2.0 mg/l BAP + 0.2 mg/l NAA from nodal segments. For survivality test (viability) of encapsulated shoot tip and nodal explants of M. arvensis under different storage temperature, 4 ± 1ºC temperature proved best for storage of artificial seeds for about 60 days.