Botany

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Assessment of Road Side Trees in Kathmandu Valley for their Air Pollution Tolerance Index and Heavy Metal Biomonitoring Ability
(Institute of Science & Technology, 2023-07) Hamal, Jaya Prakash
Bryoflora of lowland Nepal: Tarai and Churia HIlls
(Institute of Science and Technology, Botany, 2008) Pradhan, Nirmala
Though the study of bryophytes in Nepal was initiated long time before but was focused mainly upon the Himalayan species. Few available literatures on Nepalese mosses and liverworts provide very scarce information about lowland species which occur below 1000 m of elevation. My aim with this research is to explore out details of lowland bryophytes which are distributed along the east to the west lowland stripe as no such study has ever been done. This study was quite fruitful to come up with many new findings and also explored many interesting rare species which demand effective conservation measures. In connection to this research, I had an opportunity to visit the National Botanical Research Institute (NBRI), Lucknow, India where I got privilege to make a brief study on their collections and with appreciable cooperation of Dr. Virendra Nath, a Senior Bryologist; I was able to confirm some of the confusing species that I had taken with me. Some species which were not identified in Nepal were also sent to Edinburgh, UK where the well known bryologist Dr. David Long who is also my Co-Supervisor in this research shared his valuable time to identify them all. Mostly, the identification work was done at the Natural History Museum and Central Department of Botany, Tribhuvan University. Bryophyte has gained least popularity among the communities and societies of Nepal. Its sustainable use is absolutely unknown among the peoples of low land districts where this study was conducted. Some species of bryophytes carry high medicinal values like Sphagnum species which also occurs in Nepal. Bryophytes have been used for various purposes especially for horticulture, packing, as medicine for cough and cold, as green tea, stuffing materials in cushions and pillows etc. These valuable species also exist in lowland Nepal but needs education and information to village peoples about sustainable uses. This kind of practice can be expected to raise their socio-economical status. The research result of this work is incorporated into my PhD. Dissertation and is submitted to the Central Department of Botany, Tribhuvan University, Nepal. Every bryofloral species recorded in the field has been included in this work including their diagnostic features, key characters, distributional and altitudinal ranges, status and references. Hand sketching of many of the species has also been provided. This research includes some significant objectives like the survey of lowland bryophytes and their documentation, status categorization, distributional range, ecology and anatomical features of every known species of lowland Nepal. This extensive research has been expected to provide good reference to all the bryologists who are interested or study low land bryophytes of Nepal.
Carbon Sequestration Potential in community managed Forests in Mahottari District of Central Nepal
(Institute of Science and Technology, Botany, 2015) Mandal, Ram Asheshwar
Forest carbon sequestration plays a significant role in mitigation and adaptation to the impacts of the climate change. The carbon sequestration is accounted as carbon credit for reducing emission from deforestation and forest degradation (REDD+) programme. On the other hand, increasing concentration of CO2 emission contributes to green house gases (GHGs), which are mainly responsible for global warming and consequence is impacts of climate change. These, both need intensive scientific records to assess them, the former needs the records of carbon stock change while the latter one needs the record of sources of GHGs emission particularly the CO2 and CH4 emission. Such researches are very limited in Nepal. Thus, this study is objectively carried out to assess the specieswise Importance value index (IVI) and carbon stock; to assess the carbon stock in community managed forests; to identify the carbon sequestration potential and confrontation for carbon trade; to evaluate the carbon stocks for sustainable management of forests; to appraise the plant biodiversity status and its relationship with the forest carbon stock; to identify drivers of deforestation and forest degradation and its effects on carbon stocks in community managed forests and to quantify the CO2 and CH4 emission from domestic fuel and livestock keeping of household living near to forest and distant from the forests. For this study, two types of data specifically biophysical and socio-economic data were collected. The biophysical data were collected from community managed forests like three from each collaborative and community forests as well as public plantations and community planted forests of Mahottari district. In addition, socio-economic data collection was focused on drivers of deforestation and forest degradation, which were collected from workshop with key informants. Meanwhile, Sahodawa and Maisthan villages were selected for assessing the CO2 and CH4 emission from fuel consumption and cattle keeping respectively, which are sources of climate change process drivers. The maps of forest areas were prepared and stratified using GPS coordinates. Latter, altogether 96, 80, 28 and 24 permanent sample plots were distributed randomly on the maps of collaborative forests, community forests, public plantations and community planted forests respectively. The randomized block design (RBD) was set so the data were collected using stratified random sampling from collaborative and community forests. Meanwhile, the complete random design (CRD) was set to gather data applying simple random sampling from public and community planted forests. Similarly, altogether 138 households were sampled randomly after well-being ranking such as rich, medium and poor, then the quantity of fuel consumption was recorded in the morning and evening for seven days during summer and winter seasons setting RBD. Next, the record of cattle keeping was noted in order to determine the CH4 and CO2 emissions. At the same time list of drivers of deforestation and forest degradation were also gathered. The biophysical data were analyzed using the biomass equation of Chave et al. The species wise IVI was also calculated and their ranking was evaluated to know the effect of carbon on IVI. Same biophysical data were used to find out the relationship between biodiversity and forest carbon. Moreover, soil carbon was calculated applying Walkley and Black Method. Meanwhile, the carbon stocks of community forests and collaborative forests were checked applying Biolley's "Check Method" - Method du-Control and Biolley's sustainable principle. Additionally, the relationships were evaluated between carbon stocks and species richness and between carbon stocks and Simpson's evenness. The socio-economic data were analyzed using descriptive analysis. It showed that, IVI of Shorea robusta was the highest about 68.59 in Tuteshwarnath CFM while this value of Gmelina arborea was the lowest 0.4 in Gadhanta- Bardibash CFM. Meanwhile, the carbon stock of Shorea robusta was the highest 50.43±0.43 t ha-1 and this of Desmodium oojeinense was the lowest 0.01 t ha-1 in Gadhanta- Bardibash CFM. In addition, there was effect of carbon stock in species ranking. It was found that the estimated carbon stock was the highest 274.67 t ha-1 in Gadhanta- Bardibash CFM while it was the lowest in 30.34 t ha-1 in Bisbitty public plantation. The estimated current annual carbon increment (CACI) was found to be highest 2.85 t ha-1 at third year in Chyandanda community forest. However, annual carbon loss (ACL) was recorded as leakage -1.68 t ha-1 from Banke- Maraha CFM. The net value of carbon sequestration potential was US$ 5967.62. Therefore, these community managed forests can be avenue for carbon trade under the REDD+ programme. Neither community forests nor collaborative forest showed sustainability performance based on Biolley's "Check Method" - Method du-Control and Biolley's sustainable principle. Here, the issues of sustainable forest management and biodiversity should be balanced equally. The estimated R2 values indicated that there is very weak relationship between species richness and carbon stock, however, the hump- shaped relationship was exist between them. The over exploitation, grazing and forest fire were major drivers of deforestation and forest degradation, which are affecting the carbon stock. Total quantities of CO2 emission were 4792.25 t and 9235.68 t in Maisthan and Sahodawa villages respectively from firewood consumption. The CH4 emissions were 160.58 and 157.66 t yr-1 in Maisthan and in Sahodawa villages respectively from the livestock keeping, which together may emit 7367.59 t CO2 equivalents but managing the CH4 emission through biogas can offer US$ 47568.35 certified emission reduction. Therefore, it can be concluded that community managed forests are potential for carbon trade. On the other it is essential to determine the drivers of deforestation and forest degradation to address them for REDD+ programme in Nepal as well as to determine the sources of CO2 and CH4 clearly to reduce them as measures of climate change adaptation and mitigation. Keywords: Carbon sequestration, CO2 and CH4 emission, REDD+, biodiversity, community forests, collaborative forests, public plantation, community planted forest.
Comparative Bioactivities of in Vivo and in Vitro Materials of Piper longum L. and Paris polyphylla Sm
(Institute of Science & Technology, TU, 2024-11) Thapa, Chandra Bahadur; Prof. Dr. Bijaya Pant, Dr. Hari Datta Bhattarai, Dr. Krishna Kumar Pant
Piper longum L. (Piperaceae) is a valuable tropical medicinal plant used to cure a variety of diseases. Similarly, Paris polyphylla Sm. (Melanthiaceae) is a temperate or subalpine vulnerable medicinal plant used to treat a variety of diseases. However, unsustainable utilization, illegal collection and export, habitat destruction, and climate change are threatening its survival in its natural habitats. As a result, their population in natural habitats is declining. On the other hand, most research activities focus on bioactivity and chemical analysis of in vivo parts; however, research on bioactivity and chemical analysis of in vitro-cultured calli is extremely limited. In the present study, the bioactivity of in vitro and in vivo cultured parts of P. longum and P. polyphylla were compared. The most effective medium for direct organogenesis by regeneration of multiple shoots (5.33±1.15) in P. longum from nodal explants was MS medium supplemented with 1.0 mg/L TDZ. The maximum number of roots (7.0±1.0) was regenerated in MS + 1.0 mg/L IBA from in vitro shoots. Plants were also regenerated by indirect organogenesis from leaf and node explants, and by somatic embryogenesis. Callus was induced from leaf explants in MS medium enriched with 2,4-D or 2.4-D + KN, while it was induced from nodal explants in MS media enriched with NAA only. Multiple shoots were obtained in MS + 0.25 mg/L TDZ (25.33±1.52) for leaf callus and 2.0 mg/L NAA (18.33±1.50) for nodal callus. Subsequently, the maximum number of roots was regenerated from in vitro shoots by using 0.5 mg/L IBA from the leaf callus and 2.0 mg/L NAA from the nodal callus. In addition, the maximum embryogenic/nodular calli with somatic embryos (SEs) were found in MS + 1.5 mg/L 2,4-D + 1.0 mg/L KN (28.33±3.05 SEs) for leaf callus, and 1.0 mg/L NAA (12.66±2.51 SEs) for nodal callus. Nodular calli with SEs were differentiated into plantlets/seedlings in MS + 0.5-2.5 mg/L TDZ and full-strength MS media without PGRs. Similarly, P. polyphylla was also propagated in vitro using leaf explants, in which the best media for callus formation and mini-rhizomes with root differentiation were MS + 0.25 mg/L 2,4-D + 0.5 mg/L KN and MS + 2.5 mg/L KN respectively. The dichloromethane (DCM) fraction of P. longum root showed the highest antioxidant activity (IC50: 134.81±1.16 µg/mL), the highest total phenolic content (TPC), and the highest total flavonoid content (TFC) compared to other extracts of in vivo parts and in vitro callus. It showed 100% growth inhibition against five bacterial strains, such as Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus, and Bacillus subtilis, with the lowest minimum inhibitory concentration (MIC) of 5.0 mg/mL, and the minimum bactericidal concentration (MBC) of 8.35 mg/mL for S. aureus. It was more cytotoxic to brine shrimp nauplii (LC50: 156.78±5.49 µg/mL), while the crude extract of the fruit showed higher anticancer activity (IC50: 146.55±2.31 µg/mL) on U-2 OS and HeLa cell lines (LC50: 273.31±17.89 µg/mL). Similarly, the DCM fraction of the root showed higher inhibition of α-amylase (IC50: 365.21±31.021 µg/mL) and α-glucosidase (IC50: 489.07±27.966 µg/mL) compared to other extracts of in vivo parts and in vitro callus. In addition, callus suspension culture in MS medium showed that salicylic acid increased callus biomass compared to other treatments, while 100 mg/L phenylalanine resulted in the maximum antioxidant activity (IC50: 22.44±1.96 µg/mL), TPC, and TFC. Similarly, the DCM fraction of P. polyphylla showed the highest antioxidant activity (IC50: 197.06±0.635 µg/mL), TPC, and TFC compared to other extracts of rhizome and callus. It also showed 100% growth inhibition against the five bacterial strains tested, with the lowest MIC at 5.0 mg/mL and MBC at 7.5 mg/mL for E. coli. It was more cytotoxic on brine shrimp nauplii (LC50: 201.78±70.97 µg/mL). It also showed higher anticancer activity (IC50: 235.94±0.72 µg/mL) to HeLa cell lines, but the methanol fraction was more cytotoxic to MCF-7 cell lines (IC50: 211.36±0.57 µg/mL). However, the crude extract of the rhizome inhibited α-amylase (IC50: 95.45±8.71 µg/mL) and α-glucosidase (IC50: 51.40±8.62 µg/mL) more effectively than other extracts of rhizome and callus. In addition, suspension culture in MS medium revealed that salicylic acid increased callus biomass than other treatments, but liquid MS media supplemented with BAP+NAA resulted in the highest antioxidant activity, TPC, and TFC than phenylalanine or salicylic acid. LC-HRMS analysis of the DCM fraction of the root and crude extract of the callus of P. longum revealed a total of 27 compounds. Similarly, the DCM fraction of the rhizome and the crude extract of the callus of P. polyphylla exhibited a total of 31 compounds. Piper longum L. (पिपला) एक बहुमुल्य उष्णप्रदेशीय औषधीय गुण भएको बिरुवा हो, जुन विभिन्न प्रकारका रोगहरु निको पार्न प्रयोग गरिन्छ । त्यस्तै, Paris polyphylla Sm. (सतुवा) एक समशीतोष्ण वा हिमाली भागमा पाईने जोखिमयुक्त (Vulnerable) औषधीय गुण भएको बिरुवा हो, जुन विभिन्न प्रकारका रोगहरुको उपचार गर्न प्रयोग गरिन्छ । तथापि, दिगो उपयोगिताको अभाव, अवैध संकलन र निर्यात, बासस्थानको ह्रास र जलवायु परिवर्तनले प्राकृतिक बासस्थानमा यिनीहरुको अस्तित्वलाई खतरामा पारेको छ । फलस्वरुप, प्राकृतिक बासस्थानमा यिनीहरुको संख्या घट्दै गइरहेको छ । अर्कोतर्फ, अधिकांश अनुसन्धान गतिविधिहरु यी विरुवाहरुका प्राकृतिक परिवेशमा (in vivo) उत्पादन भएका विभिन्न भागहरुका bioactivity र रसायनिक विश्लेषणमा केन्द्रित छन् । तर तन्तु प्रविधिबाट (tissue culture) उत्पादित callus को bioactivity र रसायनिक विश्लेषणको अनुसन्धान अत्यन्त सीमित छ । तसर्थ, यस अनुसन्धानमा पिपला र सतुवाको प्राकृतिक परिवेशमा (in vivo) उत्पादन भएका विभिन्न भागहरु र कृत्रिम परिवेशमा (in vitro) उत्पादित callus को तुलनात्मकरुपमा bioactivity र रसायनिक विश्लेषणको अध्ययन गरिएको छ। Tissue Culture प्रविधि प्रयोग गरि कृत्रिम पोषक माध्यम (MS media) मा पिपलाको काण्डको आँख्ला (node) र पात (leaf) बाट स-साना बिरुवाहरु उत्पादन गरियो, अनि सतुवाको पातबाट पनि यसका बिरुवाहरु उत्पादन गरियो । पिपलाको आँख्लाबाट बिरुवाहरु उत्पादन गर्दा प्रत्यक्ष organogenesis विधिवाट र यसको पातबाट र सतुवाको पातबाट बिरुवाहरु उत्पादन गर्दा अप्रत्यक्ष organogenesis र somatic embryogenesis उपयुक्त देखियो । त्यसैगरी, पिपलाको आँख्ला र callus बाट धेरै संख्यामा टुसाहरु (Shoots) उत्पादन गर्नको लागी र सतुवाको callus बाट धेरै संख्यामा टुसाहरु (Mini-rhizome) उत्पादन गर्नको लागी MS पोषक माध्यममा TDZ र KN हर्मोनहरु उपयुक्त देखियो । साथै टुसाबाट जराहरु उतपादन गर्नको लागी MS पोषक माध्यममा IBA हर्मोन उपयुक्त देखियो । पिपलाको जराको Dichloromethane (DCM) extract ले अरु extract ले भन्दा बढी antioxidant activity, total phenolic content (TPC) र total flavonoid content (TFC) देखायो । यस extract ले ५ प्रकारका ब्याक्टेरियाहरु (Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus र Bacillus subtilis) को बृद्धिलाई रोकेको देखायो । त्यसैगरी, यसले Brine shrimp झिंगाका लार्भाहरुलाई सबैभन्दा कम मात्राको प्रयोगमा मारेको पाईयो । तर पिपलाको फलको crude extract ले अन्य extract ले भन्दा हड्डि र पाठेघर क्यान्सर कोषहरु प्रति उच्च क्यान्सर प्रतिरोध देखायो । जराको DCM extract ले मधुमेह रोगसंग सम्बन्धित α-amylase र α-glucosidase ईन्जाईम प्रति उच्च प्रतिरोध प्रदर्शन गर्यो । यसबाहेक, पिपलाको callus लाई MS तरल पोषक माध्यममा salicylic acid प्रयोग गरी culture गर्दा यसको तौल (biomass) अरुको तुलनामा बढाएको पाईयो, जबकि 100 mg/L phenylalanine तरल माध्यममा प्रयोग गर्दा सबैभन्दा बढी antioxidant activity, TPC, र TFC को मात्रा पाईयो । तसर्थ, tissue culture माध्यमबाट उत्पादित callus ले bioactive compound हरु उत्पादन गर्यो, जसले गर्दा anti-oxidant, antibacterial, anticancer र antidiabetic प्रतिक्रिया देखायो । त्यसैगरी, सतुवाको राईजोमको DCM fraction ले सबैभन्दा बढी antioxidant activity, TPC र TFC को मात्रा देखायो । यसले परिक्षण गरिएका सबै ५ प्रकारका ब्याक्टेरियाहरुको १००% बृद्धि प्रति अवरोध देखाएको छ । यसले Brine shrimp झिंगाका लार्भाहरुलाई सबैभन्दा कम मात्राको प्रयोगमा मारेको पाईयो । साथै यस extract ले अन्य extract ले भन्दा छातीका क्यान्सर कोषहरु प्रति उच्च प्रतिरोध देखायो । त्यसैगरी, राईजोमको crude extract ले मधुमेह रोगसंग सम्बन्धित α-amylase र α-glucosidase ईन्जाईम प्रति उच्च प्रतिरोध प्रदर्शन गर्यो । यसबाहेक, सतुवाको callus लाई MS तरल पोषक माध्यममा salicylic acid प्रयोग गरी culture गर्दा यसको तौल (biomass) अरुको तुलनामा बढेको पाईयो, जबकि MS media मा NAA र BAP हर्मोन प्रयोग गरी तरल माध्यममा culture गर्दा सबैभन्दा बढी antioxidant activity, TPC, र TFC को मात्रा पाईयो । तसर्थ, salicyclic acid र phenylalanine लाई callus suspension culture मा प्रयोग गर्दा secondary metabolite बढेको पाईयो । LC-HRMS प्रविधी प्रयोग गरी पिपलाको DCM fraction र callus को crude extract को रसायनिक परिक्षण गर्दा कुल २७ वटा रसायनिक यौगिकहरु पाईयो, तर सतुवाको राईजोमको DCM fraction र callus को crude extract को रसायनिक परिक्षण गर्दा कुल ३१ वटा रसायनिक यौगिकहरु पाईयो । केहि रसायनिक यौगिकहरु दुवै callus र विरुवाका in vivo भागहरु (जस्तै: जरा, राइजोम) मा पाइएको हुनाले यस अध्यनमा callus ले रसायनिक यौगिकहरु उत्पादन गरेको पाइयो ।
Contribution of crop diversity to the livelihoods of the local people in API NAMPA conservation area of Kailash Sacred Landscape, Nepal
(Institute of Science and Technology, Botany, 2022) Aryal, Kamal Prasad
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Diversity, Distribution, and Impacts of Invasive Alien Plant Species in Lake Cluster and Associated Landscape in Pokhara Valley, Central Nepal
(Institute of Science & Technology, 2022-09) Pathak, Hom Nath
Wetlands including lakes support high biodiversity providing essential ecosystem services, yet they are among the most vulnerable habitats worldwide. Several invasive alien plant species (IAPS) have invaded Nepal’s wetlands. However, the available data are insufficient to inform policy and management decisions. This research was carried out in the Lake Cluster of Pokhara Valley (LCPV), a Ramsar site in central Nepal, with the objectives to 1) analyze the diversity of naturalized plant species in the LCPV, 2) identify IAPS and their spatial distribution in Pokhara valley, 3) assess the level of eutrophication in the LCPV, 4) identify the pathways of introduction and dispersal of the IAPS, and 5) assess the impacts of IAPS on ecosystem services in the study area. Altogether 89 plots (20×5 m2) were sampled to record flowering plants and their cover along the shoreline of the nine wetlands that constitute the LCPV. The species were identified, classified based on their life forms (Raunkiaer’s life forms), and categorized into native and naturalized species. The variation of naturalized species richness with native species richness was analyzed by a generalized linear model. The relations of environmental variables with species composition were analyzed by ordination. A survey of roadside vegetation (201 5m  5m plots) was carried out to record the diversity and distribution of the IAPS in Pokhara valley. To assess the eutrophication status, altogether 89 water samples were collected from all nine lakes, and estimated nitrate nitrogen and total phosphorus. To analyze the impacts of nutrient contents on species richness and cover of native and naturalized species, multiple regression was used. To trace the sources and dispersal pathways of the IAPS, residents (n=56, age >37 yrs) living around the wetlands with a high level of plant invasions (Begnas, Phewa, and Rupa) were interviewed. To assess the impacts of IAPS on ecosystem services, household surveys (n=273), focus group discussions (n=19) and key informants’ interviews (n=23) were conducted among the beneficiaries of the LCPV such as the farmers, boaters, hoteliers, and fishermen. The study recorded a total of 258 species of flowering plants (73 families and 191 genera). The most species-rich family was Asteraceae (27 spp), followed by Poaceae (26 spp), Fabaceae (19 spp), and Cyperaceae (19 spp). Therophytes (29%) and Hemicryptophytes (27%) were the most common among the life forms. The richness of naturalized species increased with increasing native richness whereas the nutrients had no significant effect on the species richness of naturalized plants. The study found a total of 22 IAPS in Pokhara valley. Four of the recorded IAPS, viz. Chromolaena odorata, Lantana camara, Mikania micrantha, and Pontederia crassipes were among the 100 of the world’s worst invasive species. The most frequently encountered species were Bidens pilosa (63%), Ageratum houstonianum (61%), and L. camara (61%). In water samples of the LCPV, the phosphorus level was 0.29-1.25 mg/L and the nitrate nitrogen 0.04-0.17 mg/L. Based on these two nutrients, the wetlands of the LCPV were classified as eutrophic. According to the residents, most of the aquatic IAPS found in the LCPV were brought from the southern Tarai region of Nepal and northern India between the 1970s and 1990s. Among the IAPS, P. crassipes and Pistia stratiotes were brought for their ornamental values and Ipomoea carnea subsp. fistulosa was introduced for fencing purposes. It appears that Alternanthera philoxeroides was introduced accidentally to Phewa lake recently (observed for the first time in 2019). Local respondents had been familiar with Leersia hexandra for a long period (>50 years) and were not aware of the time and mode of its introduction, suggesting that this species could have the longest history of introduction to the LCPV. The study enlisted 18 ecosystem services obtained from the LCPV. The most cited services were water for irrigation, fish farming, livestock fodder, traditional mat materials (Machaerina rubiginosa), habitat protection, and natural beauty. The total economic benefit generated by the provisioning services of the LCPV in 2019 was estimated to be International $ 0.10 million per household per year. Before the proliferation of the IAPS (1989), the estimated economic value was almost triple (International $ 0.29 million per household per year). The decline in economic value was the most pronounced in fish production (International $ 151.1 thousand) and supply of lotus (International $ 24.1 thousand). The study revealed that the Ramsar enlisted wetlands of the Pokhara valley and the surrounding landscape have been invaded by several IAPS including some of the globally worst invasive species with significant negative impacts on wetland ecosystem services. As a recommendation, this study highlights science-based policy management for preventing the further spread of IAPS in the LCPV. It is suggested to prevention of the IAPS spread to non-invaded wetlands through public awareness and regular monitoring, and their control in the invaded wetlands through participatory approaches. Nonetheless, a well-managed IAPS in wetlands such as the LCPV not only supports the livelihood of the local people but also helps to meet national and global targets to conserve wetland biodiversity and habitats from further degradation.
ECOLOGICAL STUDY AND DISTRIBUTION OF PTERIDOPHYTE ALONG THE ELEVATIONAL GRADIENT OF PHULCHOWKI HILL, CENTRAL NEPAL
(Amrit Campus, 2023-08-14) Madhikarmi, Anita
The present study aims to find the relationship between pteridophyte richness along the elevational gradients of Phulchowki Hill, Central Nepal. The study was carried out in three elevational zones namely lower (1500-1900 masl), middle (1900-2300 masl) and upper elevation (2300- 2700 masl), starting from 1550 masl and ending to 2698 masl of Phulchowki Hill at an interval of 100 m. Random number of quadrats having 5m × 5m sizes were laid at each elevation band. SPSS- Software and Microsoft Excel were used to perform the statistical analysis. All together 46 (39 terrestrials and 7 epiphytic) pteridophyte species belonging to 28 genera and 14 families have been documented. Among the 14 families Polypodiaceae was found to be the largest family having highest number of genera followed by Pteridiaceae. However, Pteridiaceae was found as largest family on the basis of highest number of species followed by Dryopteridaceae and Polypodiaceae. Plant community properties such as species richness, diversity, and composition vary along environmental gradients. Species richness of tree species showed asymmetric hump shaped pattern of distribution with elevational gradients. The pteridophyte species richness significantly differs along the elevational gradients within different sites. Pteridophyte species like Selaginella chrysocaulis, Dryopteris carolohopei were dominant in lower elevational zone; Polystichum squarrosum, Drynaria moliis were dominant in middle and Polypodiodes hendersonii, Drynaria moliis were observed dominant in upper elevational sites. The Spearman's correlation analysis table shows elevational gradient strongly affects the pteridophytes richnes
Ecology and impact of an invasive weed Ageratina Adnophora in central Nepal
(Institute of Science and Technology, Botany, 2021) Poudel, Anju Sharma
Invasive alien species (IAS) have been increasing at an alarming rate all around the globe with significant negative impacts on the environment, ecosystem services, human health and socio-economy. Therefore, understanding the ecological features of IAS invasion mechanisms, potential shift in climatically suitable regions of IAS under future climate change scenarios, and factors influencing abundance of their biological control agents is an urgent need to better inform the management policies and practices. In this study, ecological features such as distribution (current and future), functional traits variation along the elevation gradient, ecological impacts, and influence of abiotic factor (elevation) on the abundance of a biocontrol agent of a noxious invasive weed Ageratina adenophora (Sprengel) R. King & H. Robinson were analyzed in central Nepal. Maxent model was used to predict the suitable areas of A. adenophora in Chitwan Annapurna Landscape (CHAL), Nepal under current and three future climate change trajectories based on three representative concentration pathways (RCPs 2.6, 4.5 and 8.5) in two different time periods (2050 and 2070) using occurrence data of the species in the study region, climatic variables, and topographic features. To analyze the change in area invaded by A. adenophora from the year 1990-2018 in CHAL, Landsat images were used and knowledge-based image classification technique of remote sensing was applied assigning seven rules (elevation, landuse, Normalised Difference Vegetation Index (NDVI), digital number, maximum temperature, minimum temperature and rainfall). Furthermore, spatial distribution of A. adenophora was assessed in small area of interests viz. Mahadevbesi (Dhading district), Sarangkot (Kaski district) and Ghasikuwa (Tanahun district) using both low spatial and spectral resolution (Landsat) and high spatial and spectral resolution (Worldview-2) images to find out the more accurate multispectral sensors. Six functional traits namely Specific leaf area (SLA), Leaf nitrogen content (LNC), number of floral heads per ramet, total seeds per floral head, seed size and seed mass of A. adenophora were taken into consideration for analyzing their variation along the elevation gradient of 240 2965 m asl in central Nepal. Changes in species richness, species diversity, species composition and soil chemical characteristics (Organic carbon, Total nitrogen, phosphorus and potassium) due to A. adenophora invasion was studied at two sites (Chandragiri and Simbhanjyang) in Middle Mountain region. Role of elevation on the abundance of a biocontrol agent, i.e., Procecidochares utilis Stone and on size of gall formed by this gall fly was explored. Furthermore, the effect of this agent on the stem diameter of the weed, and the capacity of the gall to act as nutrient sink was further analysed. Minimum temperature in the coldest month (bio 6) was the most important variable affecting the distribution of A. adenophora. About 38% of the CHAL area is currently climatically suitable for the weed, Middle Mountain being the most suitable one. A vii predicted increase in suitable area under future climate scenarios ranged from 1-2 % from the current suitable areas. All protected areas and three physiographic regions (Siwaliks, High Mountains and High Himalaya) are likely to gain climatically suitable areas in future climate scenarios. The upper elevational distribution limit of the weed is expected to expand by 31-48 m in future climate scenarios. The area invaded by A. adeophora increased from 0.22% in 1990 to 4.55 % in 2018. Multispectral sensors, i.e., Worldview-2 images had higher accuracy in comparison to Landsat images and provided a better scenario of species distribution. SLA, LNC, number of floral heads per ramet and total seeds per floral head decreased with the increasing elevation along the elevation gradient of 500 2500 m asl. However, different trend in functional traits was observed along elevation gradient of 1500-2530 m asl. Seed size and seed mass increased with the increasing elevation at all sites along the elevation gradients. A trade-off was noticed between seed size and seed number indicating the strategy of the weed to adapt to low temperatures at high elevations. Ageratina adenophora reduced the species richness as well as species diversity in the invaded sites. Shannons diversity index in non-invaded plots was 1.9 times higher than in invaded plots. Similarly, diversity index in non-invaded plots was 1.6 times higher than in invaded plots. Invasion by A. adenophora also caused significant change in species composition. difference in species composition between invaded and noninvaded plots. Furthermore, A. adenophora invasion increased the carbon and nitrogen content in the invaded plots. However, A. adenophora invasion had no effect on phosphorus and potassium concentration. Site-specific variation in the impact of A. adenophora was noticed. Elevation had a significant effect on the gall abundance as well as gall size. Both gall abundance and size peaked at mid elevation (1950-2000 m asl). Stem galling by the fly reduced the stem diameter of the weed and all the three nutrients (N, P and K) were higher in galls than in ungalled stems. This study indicates that the elevation is an important abiotic factor that influences the P. utilis stem gall abundance and gall size. Furthermore, the galls formed by P. utilis act as nutrient sinks. In conclusion, probability of range expansion and upslope movement as revealed by niche models and functional trait studies suggests for a need to prevent further spread of the weed in the study area. Significant negative impact on plant community and soil chemical characteristics reported in this study also emphasizes for a prompt action and management interventions to be adopted by scientific community and resource managers. As the study revealed that insect gall abundance is affected by elevation and peaks at mid-elevation range, this knowledge on gall dynamics is central to the successful management of the weed through the use of biological control agents. Keywords: Invasive species, Distribution, Functional traits, Impact, Biocontrol
Ecology and Phytochemistry of Zanthoxylum armatum DC.
(Faculty of Botany, 2022) Phuyal, Nirmala
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Ecophysiology of Spirodela Polyrhiza (L.) Schleiden (Greater Duckweed)
(Faculty of Botany, 2019) Pokharel (Bhattarai), Bindu
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Ethnobotany and Antimicrobial Study of Selected Medicinal Plants Used by Magar Community in Nawalpur District, Nepal
(Institute of Science and Technology, 2022) Nemkul, Chandra Mohini
Field survey and ethnobotanical data was collected from 2015 to 2017 in Hupsekot , Bulingtar rural municipalities and Kawasoti urban municipality of Gandaki province, Nawalpur district, Nepal focusing on Magar community. To verify traditional use of selected plant species for diarrhea, urinary tract infection, typhoid and pneumonia, laboratory tests of the extracts of the plants were performed. Methods: Data were collected by interviewing local healers and knowledgeable people. Plants were selected for laboratory tests on the basis of factor for informant consensus (FIC) and feudality level (Fl) along with use mention (UM). Plant parts dried at room temperature were used for extraction by using hexane and 70% methanol successively. The extracts in amount 50µl were used for in vitro antimicrobial tests by agar well diffusion method. Dimethoxy sulfate (DMSO) was used as negative control; ampicillin and gentamicin were used as positive control. The test bacteria were Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, Bacillus subtilis, Shigella dysenteriae and Salmonella enterica subsp. enterica serovar typhi. Phytochemical screening was performed by colorimetric method. The effective compounds present were analyzed by GC-MS analysis. Estimation of total phenolic content was done using the Folin-Ciocalteu colorimetric method. Antioxidant assays were done by DPPH free radical scavenging and H2 vi O2 scavenging methods. Results: Among 160 plant species recorded 124 species were medicinal use. Phanera vahlii, Flemingia strobilifera, Lagerstroemia parviflora, Stephania glandulifera, Tectaria coadunata, Woodfordia fruticosa, Rhododendron arboreum and Rhus chinensis were selected for gastrointestinal category; Tinospiora sinensis, Cissampelos pareira and. Azadirachta indica for urinary tract infection (UTI) category; Antidesma acidum and Aegle marmelos for the respiratory category; Callicarpa macrophylla for typhoid. Alkaloids, anthocyanosides, flavonoids, saponins, steroids, terpenoids, tannin and polyphenols were detected in the extracts. Gas chromatography and mass spectrometry (GC-MS) analysis showed that antimicrobial compounds such as 2-Methoxy-4-vinylphenol, 5(Hydroxymethyl)-2-furancarbaldehyde, Phytol, 3,5-dihydroxy-6-methyl-2,3-dihydro-4Hpyran-4-one, Stigmasterol, 1,2-Benzenedicarboxylic acid, disooctyl estser, vitamin E and squalene were present in the extracts. Methanolic extract of Rhus chinensis (RCM) showed largest zone of inhibition (ZOI) (23±0.57mm) against Escherichi coli followed by Woodfordia fruticosa (18mm) (WFM). The lowest value of minimum inhibition concentration (MIC) against Escherichia coli was <1.56mg/mL (WFM). RCM and FSM showed antimicrobial activities against Shigella dysenteriae causal bacteria of dysentery but MIC values of them were bacteriostatic.WFM (18.66±0.66mm) showed the largest ZOI against Enterococcus faecalis. The lowest value of MIC was 3.12mg/mL (WFM) against Enterococcus faecalis and it was bactericidal. WFM showed the largest ZOI against Pseudomonas aeruginosa. The lowest value of MIC against Pseudomonas aeruginosa was <1.56 mg/mL (WFM). RCM (14.66±0.33mg/mL) showed larger ZOI against Klebsiella pneumoniae and followed by WFM (13.5±0.67mg/mL) and methanolic extract of Flemingia strobilifera (FSM) (11.66mg/mL). The lowest MIC value was 6.25mg/mL of FSM against Klesiella pneumoniae and it was bactericidal. The result showed that MIC value of methanolic extract of Antidesma acidum (AAM) (12.5mg/ml) against Klebsiella pneumoniae was bacterididal. MIC of methanolic extract of Callicarpa macrophylla leaf (CMML) was 25mg/mL against Salmonella typhi. MIC value of CMML against Salmonella typhi was bactericidal. RCH (hexane extract of Rhus chinensis) (16±0.33mm) showed larger ZOI against Escherichia coli. MIC of RCH was 1.56mg/mL against Escherichia coli was bacteriostatic and kill the bacteria at 6.25mg/mL. Total phenol content (TPC) in the plant extracts had significant variation ranging from 8.15 to 336.95 mg of GAE/g of dry extract. FSM contained maximum amount of TPC (336.95±14.61 mg of GAE/g of dry extract). 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging range from 4 to 94% at 100 µg/mL concentration of the 70% methanolic extracts and 50% inhibition concentration (IC50 vii ) range from 21.59±0.26 to 1434.11±1.17 µg/mL. The best DPPH free radical scavenger was methanolic extract of Rhododendron arboreum. The methanolic extract of Woodfordia fruticosa was the best H2 O2 scavenger. Conclusion: The extracts of the plants used for diarrhea by Magars of the study area, have shown antimicrobial activity against Escherichia coli, diarrhea causing bacteria. The most effective against Escherichia coli was the extract of Woodfordia fruticosa. The extract of the plant used for UTI by magars, have shown moderate effect against UTI causing bacteria. The result also verify local us of Callicarpa macrophylla against typhoid. These plants also have DPPHradical and H2 O2 scavenging properties. Woodfordia fruticosa, Flemingia strobilifera and Phanera vahlii could be used for treatment of UTI along with local use of Tinospora sinensis, Cissampelos pareira and. Azadirachta indica. In-vitro animal tests are required for these.
Floral Species Richness Pattern in Arghakhanchi and Adjoining Areas, Nepal
(Institute of Science & Technology, 2023-12) Nepali, Baburam
The biodiversity and their pattern may vary from a broad geographic area to a small local scale due to changes in their linked components along spatial and temporal gradients. Basic knowledge of distribution, diversity, and roles is necessary for the conservation of any group of organisms. In this synthesis I examined the variations in species composition and richness patterns over various spatial gradients and how they relate to the nutrients found in the low mountainous regions of west Nepal. This thesis is based on field-survey data of vascular and lichen species, analyzed soil data as well as secondary data from published articles. The study is mainly focused on vascular plant as well as lichen species composition, richness and soil heterogeneity, which is based on direct field sampling in national and community forest of Arghakhanchi and adjoining area: Resunga forest of Gulmi district, Nepal, to compile baseline information. The survey was done in autumn and spring seasons for two consecutive years (2018-2019) at various elevations that varied from 200 to 2300 m. The primary data of vascular plants was collected by use of 10 X 10 m quadrats in stratified random sampling design along the elevational gradient. From the same sampled plots, lichen specimens and soil samples were also collected. The soil samples were chemically analyzed in laboratory. The vascular and lichen specimens were identified by comparing with already identified herbarium specimens and by following identification keys. The data was analyzed by use of various statistical techniques: Generalized linear model (GLM) regression, PerManova, DCA and CCA ordinations in R software. The elevational diversity indices (Shannon-Wiener, Simpson and Pielou’s evenness) of plant life forms were estimated. A total of 606 species of vascular plants and 47 species of lichens were found in the field. Plant life forms classified by Raunkiaer (1934) yielded the following results: 265, 37, 158, 57, and 89 species for Phanerophytes, Chamaephytes, Hemicryptophytes, Geophytes, and Therophytes, respectively. According to the different types of forests, the mixed pine forest containing Schima wallichii, Castanopsis indica, Pinus roxburghii obtained the highest vascular species richness. Capillipedium assimile is the species which obtained bear the highest Important Value Index in all three ecological regions (Tropical, Sub-tropical and Temperate). The regression results show that all vascular plants, life-forms species and lichen species follow the statistically significant elevation-dependent unimodal structure. Unimodal pattern is found as common elevational species richness pattern, but is not compulsory pattern against elevation in small areas. The explanatory factors show a stronger influence on species composition than species richness, according to correlations and canonical correlations. The Hemicryptophytes, Phanerophytes and Therophytes had significant positive relationships with elevation and soil nitrogen, whereas the Chamaephytes, and Geophytes, had a negative relationship. Elevation and nitrogen function show the uniqueness of the interplay between life forms by acting as key factors of plant dispersal. Other factors-RRI, soil pH, phosphorus, potassium show comparatively less impact in species composition. According to the appearance of a peak in species diversity at nearly the same elevation and a pattern that is similar, the diversity of vascular plants promotes the abundance of lichens. The diversity of lichens was strongly correlated with the habitat and elevation than the aspect of hills. At all levels of spatio-temporal gradients, species richness and composition patterns are strongly scale dependent. Certain variables, such as soil-related local-scale heterogeneity and slope aspect, are essential for figuring out species composition and richness trends. Based on our results, it is cleared that the study area: Arghakhanchi district and its adjoining areas provide variable habitats for vascular as well as lichen community. Open ground floor is mainly rich in native as well as alien herb plant species, which are less dominant in forests. It is clear that species composition is a more useful tool in landscape ecology and biogeography research than species richness. Therefore, plant community structure should be used as a reliable and insightful indicator in biogeography studies and conservation planning.
In vitro mass propagation and production of bioactive metabolites from Valeriana jatamansi Jones and Tinospora cordifolia (Wild.) Hook.F. & Thoms
(Institute of Science & Technology, 2023-08) Pandey, Sushma
Valeriana jatamansi Jones (Sugandhawal) is a perennial herb, belonging to the Caprifoliaceae family known for its medicinal and ethnobotanical values. The species is threatened in its natural habitats as its rhizomes and roots are used for the production of medicines in the herbal and pharmaceutical industries due to the presence of valepotriates. Similarly, Tinospora cordifolia (Wild.) Hook. f. & Thoms. (Gurjo) is a climbing shrub belonging to the Menispermaceace family and has been shown to have a variety of ethnomedicinal, pharmacological and medicinal activities. T. cordifolia is also one of the most commercially used plants in pharmacy. The phytochemical and pharmacological properties of these two species have been extensively studied worldwide. However, in the context of Nepal, they are yet to be explored. In the case of V. jatamansi Jones, research has been carried out to optimize an efficient plant tissue culture system for mass propagation. The nodal segments taken from the in vitro plants developed on BAP (2 mg/L) with different PGRs at different concentrations and 10% coconut water produced the maximum shoot length (6 cm), shoot number (13.1), root length (7.5 cm), and root number (19.6). RAPD and ISSR markers were used to confirm the genetic integrity of the in vitro plants, acclimatised plants and wild plants. The effects of sodium nitroprusside (SNP), a nitric oxide (NO) donor, and various growth regulators on callus induction and shoot organogenesis of V. jatamansi were investigated. 1.5 mg/L of 1-Naphthaleneacetic acid (NAA)+15 µM SNP induced the highest callus frequency (91.18%). Maximum in vitro shoot multiplication was observed with 10% CW+15 μM SNP (89.32%). In addition, IAA, IBA, NAA and the elicitors methyl jasmonate (MeJA) and salicylic acid were added to adventitious root cultures of V. jatamansi Jones to analyse the production and growth kinetics (SA). Among the plant growth regulators studied, NAA (2.0 mg/L) induced maximum biomass (PGRs). MeJA, increased the biomass of the root cultures as compared to SA. Root cultures were analysed for their phytoconstituents and antioxidant potential. Methanolic in vitro extracts of the roots of V. jatamansi in NAA (2 mg/L) gave the highest content of phenols (55±1.00 mg GAE/g), flavonoids (219±1.00 mg QE/g) and DPPH activity (84.33±0.577%) as compared to the wild plants. Compared to NAA, the elicitor MeJA produced more biomass but less phytoconstituents. SA did not produce significant biomass. The GC-MS analysis showed that the roots treated with NAA accumulated 50 bioactive compounds, similar to the roots of the wild plants, which contained 48 compounds. Valepotriates such as valeric anhydride, valeric acid, and derivatives were found in areas of the treated roots that had higher concentrations than those of the wild plants. The MeJA-treated cultures accumulated 21 compounds while the SA elicitation accumulated 23 compounds, including derivatives of valeric acid. The examination of gene expression using the sesquiterpene synthase genes revealed that the TPS2 gene expression was significantly higher in both samples (more than five fold increase) while TPS5 had the highest gene expression (16 fold) and TPS6 had a four-fold increase in the NAA treated in vitro root cultures compared to the in vivo root cultures. In T. cordifolia, the explants of nodal segments were first treated in MS with different doses of BAP and/or KIN, with MS+BAP (2.0 mg/L) and the nodal segments were treated with various concentrations of BAP, BAP+KIN, and coconut water for proliferation of which, 5 mg/L induced significant shoot induction (9.0 shoots per explant), and mean shoot length (8.0 cm). Nodal segments proliferation increased when the media were supplemented with nodal segments at 5% and 10%. However, the addition of MS BAP (5mg/L)+10% coconut water induced maximum response with shoot number (24.0) and mean shoot length (12 cm). The genetic fidelity of these plants was also confirmed by RAPD and ISSR marker analyses in wild and in vitro cultures. Total phenolic content (TPC) was highest in wild stem followed by in vitro plant extract and wild leaves. The TFC content, and antioxidant potential were highest in wild stems followed by the wild leaves and the in vitro plant. (TPC; wild stem 128.55±0.491 mg/g, in vitro plant 107.33±0.985, wild leaves 105.6847±1.060) (TFC wild stem; 83.61±0.2773 mg/g, in vitro plant 58.034±0.148, wild leaves 62.50±0.329). Antioxidant activity; wild stem with (IC50 193.229±0.013), in vitro plant with (IC50 219.83±0.468), wild leaves with (IC50 204.386±0.165). GC-MS Analysis of the wild stem revealed the presence of 40 compounds and 31 compounds in the in vitro plant detecting various bioactive compounds including palmitic acid. In the present study mass propagation through in vitro cultures of V. jatamansi and T. cordifolia, and phytochemical screening of both V. jatamansi and T. cordifolia were standardised which is the first of its kind with respect to these species in Nepal. Root cultures establishment, characterization of valepotriates in adventitious root cultures of V. jatamansi and expression of the sesquiterpene synthase gene was successfully developed
Mass propagation and ex-Situ conservation of cymbidium aloifolium (L.) Sw., A threatened medicinal Orchid of Nepal through artificial seed technology
(Institute of Science and Technology, Botany, 2017) Pradhan, Shreeti
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Phytochemical Analysis and Biological Activities of Some Selected Medicinal Plants of Nepal
(Faculty of Botany, 2022) Shrestha, Shyam Sharan
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Plant Species Diversity and Biomass in the Forests of Morang District, east Nepal
(Institute of Science & Technology, TU, 2024-08) Gachhadar, Pramila Kumari; Dr. Chita Bahadur Baniya, Dr. Tej Narayan Mandal
Tropical forest ecosystem is crucial for mitigating the effects of climate change, because it acts as a carbon sink. Additionally, forest is the home to a significant portion of world’s biodiversity. Species composition, diversity, and biomass thought to be changed along the increasing elevation. The objective of the present study was to determine the variation in soil characteristics and their effect on species composition, diversity, biomass, carbon and nutrient stocks in the forests located along elevation gradient in Morang district of east Nepal. Five forest sites located at different elevations were selected which are addressed here as Bhaunne (200 m), Raja-Rani (500 m), Murchungi (800 m), Adheri (1000 m) and Sagma (1200 m), which lie inside the five different community forests in Morang district. A total of 50 sampling plots, 10 from each forests were laid randomly. Sampling size for tree was 20 m x 20 m, for shrubs nested 5m x 5m and for herbs nested 1m x 1m. Soil was collected by soil monolith of 10 cm x 10 cm x 30 cm, which was also used for fine root collection and litter mass was collected by using 1 m x 1 m sampling size within the plots used for tree sampling. Trees (≥10 cm girth) biomass and shrubs biomass was estimated by girth: biomass allometric equation. Herb biomass was estimated by harvest method. The carbon content of each plant components were estimated by ash content method. The data were analyzed by MS excel and R-package. Plot wise generalized linear model up to first order showed that the total species richness, herbs species richness and shrub species richness statistically significantly inclined and tree species richness statistically significantly declined pattern with increasing elevation. Total biomass and tree biomass showed declined relationship with elevations. While, shrub biomass showed statistically not significant inclined pattern and herb biomass showed statistically significant inclined pattern with increasing elevation. Shorea robusta was a dominant tree species with the highest Important Value Index value in the four forests except Sagma. Schima wallichii was the dominant species with the highest IVI in Sagma. Sorensen’s similarity index of trees revealed 64% similarity between Murchungi and Adheri forests, while lower similarity (22%) was exhibited between Bhaunne (extreme lower elevation) and Sagma forest (extreme high elevation). Stand biomass (815.88 Mg ha-1) and carbon stock (333.63 Mg C ha-1) were maximum in lower elevation forest (Bhaunne), while minimum biomass (299.96 Mg ha-1) and carbon stock (140.19 Mg C ha-1) were found in higher elevation forest (Sagma). Litter mass ranged between 7.1 Mg ha-1 and 25.7 Mg ha-1 showing irregular trend even in carbon and nutrient stock (N, P, K) due to irregular variation in non–leaf (wood) component of litter mass. Leaf litter exhibited close C: N ratio than non-leaf (wood) litter indicating a fast decomposition and nutrient release in the ecosystem. Fine root biomass ranged from 7.14 Mg ha-1 to 16.0 Mg ha-1. Carbon and nutrient stocks in fine root followed the same trend as per the trend in biomass. Fine root of <2 mm diameter size contained higher biomass than 2-5 mm size. Further, C: N ratio in <2 mm size was narrow than 2-5 mm size which is expected to release more nutrients in the ecosystem. Soil moisture ranged between 8.48 % and 21.29 %, water holding capacity from 68.21 to 97.48%, pH from 5.06 to 5.68, organic carbon from 1.20% to 3.04%, total nitrogen from 0.12 to 0.26% in different forests located along the different elevations. The lower elevation forest (Bhaunne) contained maximum soil moisture, organic carbon and total nitrogen, representing a healthy condition for the ecosystem. The soil moisture and fine root biomass were the most significant predictors for the tree species richness. Similarly, elevation, moisture, and non-leaf litter mass were significant for shrub species richness (Elev: p < 0.01, Moist1: p < 0.01, NLP: p < 0.05). The total nitrogen and leaf litter mass were important for herb species richness with p values; < 0.001 and < 0.01 respectively. In conclusion, variation in elevation has the effect on change in soil properties, plant density, plant diversity, biomass, carbon and nutrient stocks which accumulate in interdependent way. Findings of the present study may help to formulate a strategy for the management of productive forest to mitigate the carbon emission. उष्णकटिबंधीय वन पारिस्थितिक प्रणाली महत्त्वपूर्ण छ, किनभने यसले कार्बन भण्डारको रूपमा काम गर्दछ । प्रजाति संरचना, जैविक विविधता (Biodiversity), र जैविक पिण्ड (Biomass) बढ्दो उचाइसँगै परिवर्तन हुने गर्दछ । यो अध्ययनको उद्देश्य माटोको विशेषतामा हुने भिन्नता र वनमा रहेका प्रजातिहरूको संरचना, विविधता, जैविक पदार्थ, कार्बन र पोषक तत्वको भण्डारमा प्रभावको अध्ययन हो, जसको लागि मोरङ जिल्लामा भाउने (२०० मिटर), राजा-रानी (५०० मिटर), मुरचुङ्गी (८०० मिटर), अधेरी (१००० मि.) र साग्मा वन (१२०० मि.) गरी पाँच वटा वन छनोट गरिएको थियो, जुन सामुदायिक बन अन्तर्गत पर्दछ । ५० नमूना प्लटहरू, प्रत्येक वनबाट १० प्लटहरू अनियमित ढांचा अनुसार रूख (Trees) को लागि नमूना आकार २० मि. x २० मि., बुट्यानहरू (Shrubs) को लागि ५ मि.x ५ मि. र साना झाडीहरू (Herbs) को लागि १ मि.x १ मि. थियो । माटो १० से.मि. x १० से.मि. x ३० से.मि. को मोनोलिथद्वारा संकलन गरिएको थियो, जुन मसिना जरा सङ्कलनका लागि पनि प्रयोग गरिएको गरिएको थियो । कुल प्रजातिहरू, बुट्यान र साना झाडी प्रजातिहरू बढ्दो उचाइको साथ सांख्यिकीय रूपमा महत्त्वपूर्ण बढ्दो ढाँचा देखायो र रूख प्रजातिहरू बढ्दो उचाइसँगै गिरावट प्रवृत्ति देखाएको छ । कुल जैविक पिण्ड (Total stand biomass) र रूख जैविक पिण्ड (Tree biomass) ले सांख्यिकीय रूपमा महत्त्वपूर्ण रूपमा घटेको सम्बन्ध देखाएको छ, जबकि बुट्यान जैविक पिण्ड (Shrub biomass) र झाडी प्रजातिको जैविक पिण्ड (Herb biomass) ले बढेको ढाँचा देखायो । Important Value Index को आधारमा, साल (Shorea robusta) तलको चारवटा जंगलहरुमा र चिलाउने (Schima wallichii) साग्मा (माथिल्लो) वनमा प्रभुत्व छ । सोरेन्सेनको रुखको समानता सूचकाङ्कले मुरचुङ्गी (८०० मि.) र अधेरी जंगल (१००० मि.) बीच ६४ प्रतिशत समानता देखाएको छ । जबकि भाउन्ने (२०० मि.) र साग्मा वन (१२०० मि.) बीच कम समानता (२२%) प्रदर्शन गरिएको थियो । कूल वनस्पतिमा अधिकतम जैविक पिण्ड, ८१५.८८ Mg ha-1 र कार्बन स्टक, ३३३.६३ Mg C ha-1 भाउन्ने बनमा पाइयो भने न्यूनतम बायोमास, २९९.९६ Mgha-1 र कार्बन स्टक, १४०.१९ Mg C ha-1 साग्मा वनमा पाइयो । पातपतिंगर ७.१ Mg ha-1 र २५.७ Mgha-1 को बीचमा पाइयो । मसिनो जराको जैविक पिण्ड (Fine root biomass) ७.१४ Mg ha-1 देखि १६.० Mg ha-1 सम्म, भाउने जंगलमा न्यूनतम र मुर्चुङ्गी वनमा अधिकतम पाइयो । २ मि.मी. व्यास भएको जराले अधिकतम र २-५ मि.मी.ब्यास भएको जराले कम बायोमास देखायो । माटोको आर्द्रता ८.४८ % र २१.२९ %, पानी धारण क्षमता ६८.२१ देखि ९७.४८ %, pH ५.०६ देखि ५.६८ , जैविक कार्बन १.२० % देखि ३.०४ %, कुल नाइट्रोजन ०.१२ % देखि ०.२६ % सम्म पाइयो । भाउने वनमा अधिकतम माटोको आर्द्रता, जैविक कार्बन र कुल नाइट्रोजन रहेको थियो, जसले पारिस्थितिक प्रणालीको लागि स्वस्थ अवस्थालाई जनाउछ । माटोको आर्द्रता र मसिना जरा बायोमासले रूख प्रजातिहरूको वृद्धिको लागि सबैभन्दा महत्त्वपूर्ण रहेको पाइयो । त्यसैगरी, उचाइ, आर्द्रता, र गैर-पात लिटरमास झाडी प्रजातिहरूको लागि महत्त्वपूर्ण थियो। कुल नाइट्रोजन र पात लिटरमास झाडी प्रजातिहरूको लागि महत्त्वपूर्ण पाइयो । अन्तमा, उचाइको भिन्नताले माटोको गुण, बिरुवाको घनत्व, बिरुवाको विविधता, जैविक पिण्ड, कार्बन र पोषक तत्वको भण्डारमा प्रभाव पार्छ जुन एक अर्कामा निर्भर हुन्छ । वर्तमान अध्ययनका निष्कर्षहरूले कार्बन उत्सर्जनलाई न्यूनीकरण गर्न, उर्बर र उत्पादक वन व्यवस्थापनको रणनीति बनाउन मद्दत पुग्नेछ ।
“Population Ecology and Harvesting Sustainability of Aconitum spicatum and Dactylorhiza hatagirea in Nepalese Himalaya”
(Institute of Science & Technology, 2023) Chapagain, Deep Jyoti
The harvesting of Medicinal and Aromatic Plants (MAPs) is a customary subsistence activity of forest-dependent communities across the world. However, the harvesting and marketing of MAPs has been highly commercialized in recent years, leading to the colossal pressures on the MAPs resource base. Many MAPs like Aconitum spicatum and Dactylorhiza hatagirea have been threatened in the Himalaya due to unsustainable harvest. At the same time, scientific knowledge on the demographic properties, magnitude of harvest impact, and the long-term viability of populations of these plant species is largely lacking thus limiting our ability to develop sustainable management strategies. Thus, this research was designed to understand the population ecology and harvesting sustainability of A. spicatum and D. hatagirea in the Annapurna Conservation Area and Manang in Central Nepal, and Darchula in Western Nepal. Different levels of tuber harvesting (0%, 25%, 50% and 75%, where 0-25% represents low harvest intensity and 50-75% represents high harvest intensity) were applied directly by the locals for A. spicatum among three ecotonal populations (subalpine, lower alpine and alpine) along an elevation gradient (3000–4200 m a.s.l.) in Annapurna Conservation Area, North-Central Nepal. For D. hatagirea, two sites were selected: Manang, where harvesting of MAPs was locally regulated (protected); and Darchula, where harvesting was locally unregulated (unprotected) to see the effect of harvesting on its demographic parameters. Population density and structure of A. spicatum was studied and variation in its life history traits among three populations along the elevation gradient in Central Nepal was assessed. The results showed that human disturbances and topographic factors greatly contributed to the variation in density and life history traits. The overall density ranged between 0.56 ± 0.09 (mean ± SE) and 2.48 ± 0.24 plants/m2 with highest mean density in the lower alpine and lowest in the subalpine population. Harvesting, animal droppings and fire appeared to be the most important factors affecting density of A. spicatum at its different life stages. The demographic data of A. spicatum included 4-year observations on growth, fecundity and survival of individuals classified by size. The population dynamics of A. spicatum in three different populations along the elevation gradient in Annapurna Base Camp Region, North-Central Nepal was studied. The population growth rate (λ) was >1 in low harvest intensity (0-25%) in all the populations in all the transitions (2015-2018) indicating that the harvesting of this plant at low harvest intensity is sustainable. In the high harvest intensities (50-75%), the lambda value was <1 in lower elevation populations indicating that these populations are sensitive to high harvest. The results showed that the extinction probability derived from the stochastic simulation (1000 runs) in 100 years has extremely low value for all the populations in both the intensities. Transient dynamics revealed that the low harvested alpine population shows gradual increase in its population reaching a size of approximately 4000 individuals during the projection period of 10 years. The deterministic projection revealed that the subalpine population is the most sensitive population. The populations of subalpine (both low harvest and high harvest) can reach the low harvest intensity of alpine in more than 20 years. The high harvest population of viii subalpine requires 22 years to reach its low harvest intensity in contrast to 7 years of lower alpine. The higher contribution of large size classes to λ indicates that the larger size classes are the critical stages in the life cycle of A. spicatum and conservation priority should focus on the protection of theses stages. Population density, structure, and tuber biomass of D. hatagirea were studied and compared in seven different populations. Mean density of D. hatagirea was significantly higher in the locally protected (1.31 ± 0.17 plants/m2 ) than in the unprotected (0.72 ± 0.06 plants/m2 ) site. The protected site showed stable population density with high reproductive fitness and tuber biomass over the three-year period. The densities of different life-stages were highly sensitive to harvesting and livestock grazing. Significant interactions between site and harvesting and grazing indicated particularly strong negative effects of these disturbances on densities of juvenile and adult reproductive stages in the unprotected site. A matrix population model was prepared to explore variation in demographic parameters in response to different level of disturbances. In case of D. hatagirea, demographic data included 2-year observations on growth, fecundity and survival of individuals classified by size. Transition probabilities for stage-based population projection matrices varied between populations and among years. The population growth rate (λ) was less than 1in unprotected (Darchula) and more than 1 in protected (Manang) site. The unprotected populations can resume its sustainable growth at 10- fold increase in its present fecundity while the present protected populations would allow approximately 10% of the populations to be harvested locally maintaining sustainability. The wetland population requires 25-fold increase in its present fecundity to maintain the stable size. Elasticity analysis shows that the juvenile and reproductive adult stages are the critical life stages of D. hatagirea in unprotected and protected site respectively and should be conserved with greater priority. Semi-structured interviews were conducted with informants (n = 65 for A. spicatum and n = 186 for D. hatagirea) in the villages and at the ecological survey sites. The result shows that the population of A. spicatum is decreasing due to indiscriminate harvesting by the outsiders and the locals are highly responsible for the conservation of A spicatum of that area. In case of D. hatagirea, populations at the protected site are well maintained with almost constant density over years but populations at unprotected sites greatly fluctuated in density. It is concluded that the long-term viability of A. spicatum and D. hatagirea largely depends on the magnitude of harvest impact and the level of protection provided directly by local people; and the opportunities of sustainable harvest vary among plant species with different strategies of growth and demographic properties, and these further relate with ecological conditions set by elevation gradient. Sustainability of harvest of A. spicatum and D. hatagirea can be achieved through integrating species specific ecological studies, and knowledge and practices of key knowledge holders. The findings of this research suggest that strategies and actions towards reducing human induced disturbances like over-harvesting and grazing would greatly benefit population recovery and productivity of theses plant species.
Population Ecology and Harvesting Sustainability of Neopicrorhiza scrophulariiflora in Nepal Himalaya
(Institute of Science & Technology, T.U., 2024-06) Poudeyal, Mukti Ram; Prof.Dr. Suresh Kumar Ghimire
Wild plant resources, including especially medicinal and aromatic plants (MAP) have great ecological, cultural, and economic value and contribute significantly to people's livelihoods in many of the world's rural areas. Additionally, it is widely acknowledged that the sustainable use of MAPs derived from natural ecosystems is an essential instrument for enhancing rural economies and forest protection through poverty reduction. A number of connected issues of social, ecological, cultural, and environmental character must be addressed when the commercialization and sustainable use of wild MAPs are envisioned in a single paradigm. This thesis takes a step in that direction and uses a social-ecological approach to develop a model for sustainable harvesting of Neopicrorhiza scrophulariiflora which seeks to create consistency between production and the renewable resource supply from the Nepalese Himalayas. We concentrate on how ecological changes drastically altered plant distribution and how resource availability connects to usage patterns across Nepal (via trade and transportation systems). We tested whether the variation of harvest (experimental harvest: removal of 0-100% of the plants) and the ecological conditions (lower alpine, <4250 m, vs upper alpine, >4250 m) affect population structure, reproduction, growth rates, and population dynamics in commercially open and protected regions in northwestern and north-central Nepal. The area of the potential distribution of the species was calculated to be 11617 km2, corresponding to 8% of Nepal's land area and primarily located in the eastern highlands. Particularly suitable habitat areas (386 km2; 0.3% of the land area) tended to lie in the narrow altitude range of 4000-4400 m above sea level, especially in the central and eastern regions. The plant species prefer mild temperatures and sufficient rainfall in the middle of the growing period (June-August), and such conditions often occur in the mentioned areas. On the other hand, decreasing rainfall and greater temperatures diminished the suitability of the habitat in the western regions where the populations are intensively harvested with a view to commercial exploitation. Over 12 fiscal years, available official records showed that a total quantity of dried rhizomes of 372 tons (31 tons/year) valued at USD 591570 was exported to other countries. Of this, 92% of the amount came from western Nepal, which indicates that the current resource utilization is not sustainable. In the protected area, the recent harvest, which was largely carried out by locals (de facto harvest), had a positive effect on population density for vegetative and a negative effect on reproductive individuals, while it had a negative effect on all plant stages in the area where exploitation is unregulated. Harvesting involves a trade-off between vegetative regrowth (clones) and sexual reproduction, and flowering was reduced when harvesting intensity increased. Apparently, the growth rate of the populations is positive and occurs predominantly by clonal reproduction in the unregulated area and sexual reproduction in the protected area. Clonal behavior, such as fugitive recruitment and accelerated bud production, can help a plant mitigate the detrimental impacts of harvesting and, theoretically, boost the harvest potential. Mixed-effects statistical models were used to model data from simulated harvest experiments and showed that recovery of population density and sexual reproduction varied significantly depending on harvest treatments and pre-harvest plant density. In lower alpine populations at the protected site, both density and reproduction were restored within three years after harvesting up to 50% of the plants, and within one year after harvesting up to 25% of the plants. In contrast, recovery to pre-harvest conditions at the unregulated site was only achieved after one year of harvesting 25% of the plants. Post-harvest recovery was slower at higher altitudes (upper alpine, >4250 m) and plots with more intensive harvesting (>50% harvesting) recovered more slowly. Based on matrix modeling, it was found that the population growth rate (λ) when removing up to 25% of the plants made it possible to maintain the pre-harvest condition at a 2-year harvest interval in almost all the studied populations. In the protected area, population growth was unaffected by the removal of up to 50%, and instead, the growth rate increased more than in the control plots. At the high alpine sites in the unregulated area, however, the growth rate was decreasing, even on the control plots, and harvesting had a further detrimental effect on the populations, making it necessary to use relatively long time intervals between harvests to achieve stability. Selective harvesting of particular developmental stages was difficult to achieve, nevertheless, it is considered worthwhile to leave 20-25% of the fruiting ramets at each harvest if 25% of the plants have flowered. In general, we strongly recommend that in order to achieve sustainable harvesting spatio-temporal rotations be introduced, so that a time interval of at least four years is achieved between harvesting activities in a given area and so that the plants are given a minimum amount of time to mature. वनजन्य वनस्पतिहरु मध्ये बिशेषगरी औषधिजन्य जडिवुटिको पास्थितीक, सांस्कृतिक तथा आर्थिक महत्व रहेको हुन्छ । संसारभरिनै जडिवुटिको परम्परागत स्थानिय औषधोपचार तथा बेचविखनबाट हुने नगद आम्दानीलाई ग्रामिण आधारभूत आवश्यकता र जनजीविकाको आयआर्जनको मेरुदण्दको रुपमा लिइन्छ । यसको दिगो संकलन र व्यबस्थापनलाई गरिबी निबारण तथा वनको संरक्षण सम्बर्धन गर्ने महत्वपुर्ण औजारको रुपमा पनि लिर्ईएको पाईन्छ । तर जब औषधिजन्य जडिवुटि वनस्पतिको व्यापारिकरण संगसँगै बढ्दो माग तथा बजार मूल्य र त्यस अनुसारको दोहन एउटै परिदृश्यमा देखा पर्दछ त्यसैसंगै आउने सामाजिक, आर्थिक तथा सांस्कृतिक अवयवहरुलाई समन्वात्मक तवरले समाधान खोजीनु अपरिहार्य रहन्छ । यीनै समस्या समाधानको शुत्राधारको लागि जडिवुटिको सामाजिक–पारिस्थितिक अवधारणालाई लिएर स्रोतको अनवरत उत्पादन, प्रयाप्तता तथा समुचित प्रयोगार्थको लागि सदियौंदेखि उपचार पद्दतीमा आईरहेको तथा राष्ट्रिय र अन्तरराष्ट्रिय व्यापारिकरण भई दोहन भईरहेको उच्च हिमाली वनस्पति कुट्की (न्योपिक्रोराईजा स्क्रोफुलारीफ्लोरा) को दिगो संकलनको विधि, धाचा तथा दिर्घकालीन व्यावस्थापन रणनिती तयार पार्न सहयोग गर्नु नै यो शोधकार्यको प्रमुख उद्देश्य हो । विशिष्टिकृत रुपमा नेपालभरी पारिस्थिक प्रणाली अनुसार प्राकृतिक विचरणमा पार्ने प्रभाव, स्रोतको उपलब्धता, प्रयाप्तता तथा सुनिश्चितताका र त्यस अनुसारको संकलन, बेचबिखन र पैठारी रहेको वा नरहेको छुट्याउनु नै अध्ययनको पहिलो उद्देश्य थियो । त्यस्तैगरी भिन्न पारिस्थिक प्रणाली [उच्च 󠆅(समुन्द्रि सतह बाट ४२५० मि. भन्दा कम) तथा न्युन (समुन्द्रि सतह बाट ४२५० मि. भन्दा बढि) हिमाच्छेदीत भूभागहरुम] अनुसार विभिन्न स्तरको (०%, पूर्ण नियन्त्रण देखि १००%) कटान परिक्षण प्रयोग गर्दा विरुवाको जनसांखिक संरचना, प्रजनन क्षमता, वृद्धिविकाश तथा समग्र जनसांखिक बनोटको उलट–पुलटमा पार्ने प्रभावको मुल्यांकन गर्ने र न्युन क्षतिमा उच्चतम लाभ लिने विधि पत्ता लगाउनु सोधकार्यको अर्को उद्देश्य थियो । यसका लागि नेपालको उत्तरी हिमाली भूभागमा स्थानिय प्रयोगको लागि तथा व्यापारिक कटान तथा संकलनका लागि खुल्ला अपिनाम्पा संरक्षण क्षेत्र र व्यापारिक संकलनका लागि प्रतिबन्धित लाङ्टाङ राष्ट्रिय निकुञ्जमा दिर्घकालिन प्लट बनाई सन् २०१५ देखि २०१८ सम्म परिक्षण अध्ययन गरियो । जि. आई. एस्. विधिको अध्ययन अनुसार नेपालमा कुट्कीको संभावित विचरण क्षेत्र ११६१७ स्क्वाएर कि. मि. (करिब ८%) रहेको छ । जसमध्ये पुर्वी तथा मध्य उच्च पहाडी भूभागको ३८६ स्क्वाएर कि. मि., करिब ०.३% मात्र उत्तम गुणस्तरीय वासस्थान पाईएको र समुन्द्रि सतहबाट ४००० मि. देखि ४४०० मि. को उचाईमा मात्र साघुरिएर रहेको पाईन्छ । वातावरणीय अनुकुलनताको आधारमा विरुवाले उसको उच्चतम वृद्धि हुने समय जस्तै जून देखि अगस्त महिनामा मध्यमस्तरीय तापक्रम र उचित मात्राको बर्षात हुने ठाँउमा राम्रो भएको पाईयो । छोटो तथा न्युन बर्षात र उच्च तापक्रमका कारणले गर्दा पश्चिम नेपालतिर वासस्थानको गुणस्तर घट्दै गएको पाईन्छ । बिगत १२ बर्षको सरकारी आँकडा अनुसार नेपालबाट जम्मा ३७२ टन (मूल्यः करिब ५९१५७० अमेरिकन डलर, औसतमा प्रतिवर्ष ३१ टन) निकासी हुने गरेको र सबै तौलको करिब ९२% पश्चिम नेपालबाट मात्र भएको पाईयो । अधिक न्युन गुणस्तरको वासस्थानको उपलब्धता तथा अधिक दोहनलाई सँगै जोडेर हेर्दा समग्र नेपालमा अहिलेको संकलन प्रणाली दिगो नभएको पाईएको छ । तथापि व्यापारिक रुपमा खुल्ला तथा प्रतिबन्धित क्षेत्रमा भएको भौगोलिक प्रत्यक्ष अध्ययनमा स्थानिय उपचारको लागि गरिने परम्परागत संकलन परिमाण दर उस्तै रहेको पाईएको छ । कुट्कीको जनघनत्वमा भैरहेको स्थानिय तदर्थ दोहनको प्रभाव मुल्यांकन गर्दा प्रजनन र अप्रजनन दुवै अवस्थाका विरुवामा खुल्ला क्षेत्रमा नकारात्मक असर रहेको तर प्रतिबन्धित क्षेत्रमा अप्रजनन अवस्थाका विरुवामा सकारात्मक असर रहेको थियो । मध्यम स्तरको दोहनले प्रजनन र अप्रजनन वृद्धिको छेकबार/बन्देजलाई बढाउने सेतुको रुपमा रहेको र जव दोहनको स्तर बढ्छ विरुवामा कोपिला लाग्ने दर रेट घटेको पाइयो । अतः विरुवाको जनसांखिक वृद्धि खुल्ला क्षेत्रमा अप्रजनन प्रसारणसँग र प्रतिबन्धित क्षेत्रमा प्रजनन प्रसारणसँग केहि सकारात्मक सम्बन्ध रहेको थियो । विरुवामा रहेको अप्रजनन प्रसारणजन्य गुणहरु जस्तै मौका मिल्दा हुने अप्रत्यासीत अंकुरण क्षमता तथा सामान्य अवरोधको बदलाभमा नयाँ नयाँ पालुवा अंकुरण हुने क्षमताको बिस्तार गर्न सक्ने शंचित शक्ति प्राकृतिक रुपमै भएकाले कुट्कीमा केहि हदसम्म कटानको नकारात्मक प्रभावलाई सहन सक्ने निष्कर्श निकालियो । तथ्यांकीय विष्लेशण रिपिटेड मिक्स्ड इफेक्ट मोडलीङ्का अनुसार कटान संकलन पश्चात हुने जनघनत्व अंकुरण भरण तथा प्रजनन उत्पादन संकलन—कटान दरमा तथा कटान गर्नु भन्दा अगावैको जनघनत्वमा भरपर्ने र सकारात्मक सम्बन्ध रहेको पाईयो । प्रतिबन्धित क्षेत्रको न्युन (समुन्द्रि सतह बाट ४२५० मि. कम) हिमाच्छेदीत भूभागमा ५०% सम्म कटान गर्दा परिक्षण अवधिको तिन वर्षमै पुनःभरण भएको र २५% सम्मको कटान प्रत्येक वर्ष गर्दा पनि पुनःभरण हुने परिणाम पाईयो । तर खुल्ला क्षेत्रको समान स्तरको भूभागमा उक्त अवधिमा २५% कटान मात्र पुनःभरण भएको पाईयो । कटान पश्चातको पुनःभरण क्षमता भौगोलिक उचाई बढ्दा तथा कटान प्रतिशत दर बढाउदा घटेको पाईयो । पुनःभरण क्षमता प्रतिबन्धित क्षेत्रको तुलनामा खुल्ला क्षेत्रमा धेरै ढिलो भएको पाईएको छ । अर्को तथ्यांकीय विष्लेशण म्याट्रिक्स मोडलीङ्का अनुसार लगभग सबै ठाँउमा विरुवाको जनसांखिक वृद्घिदर २५% सम्म कटानको दुई बर्षको अवधिमै सकारात्मक स्तर भन्दा माथि रहेको पाईयो । बिषेशगरी प्रतिबन्धित क्षेत्रको न्युन हिमाच्छेदीत भूभागमा ५०% सम्मको कटानले विरुवाको जनसांखिक वृद्घिदर उक्त अवधिमै कटान परिक्षण अगाडिको भन्दा अझ वढेको भेटिएको छ । तर खुल्ला क्षेत्रको उच्च हिमाच्छेदीत भूभागमा जनसांखिक वृद्घिदर कटान नियन्त्रित परिक्षण अवस्थामै पनि घटिरहेको हाम्रो अध्ययनमा पाईयो । विरुवाको जनसांखिक मुल्यांकन अनुसार परिपक्व उमेरको विरुवा छनौट विधिबाट गरिने कटान संकलन त्यति व्यावाहरिक नभएको र प्रत्येक कटान समयमा कम्तिमा २०—२५% फूलफल लागेका विरुवा रहने गरी भएमा वा प्रत्येक जनसांखिक संरचनामा उक्त २०—२५% फूलफल लागेका विरुवा सुनिश्चित भएमा मात्र कटान अनुमति दिन मिल्ने देखिन्छ । कुट्कीको दिगो संकलन, क्षति न्यूनिकरण, र जनसांखिक सुनिश्चितताका लागि समय र ठाँउ अनुसारको रणनितिक कटान—संकलन व्यावस्थापन गर्नुपर्ने र प्रत्येक चार बर्षे अन्तरालको अवधिमा मात्र कटान अनुमति दिन सकिने यो सोधकार्यको सुझाव रहेको छ ।
Responses of Some Vegetable Crops to Toxic Heavy Metals
(Central Department of Botany Institute of Science and Technology Tribhuvan University Kirtipur, Kathmandu, 2008) Sharma (Kafle), Baby
Some common green vegetables (Brassica juncea, Brassica rapa, Lactuca sativa, Lepidium sativum and Daucas carota) of Kathmandu valley have been investigated for the morphological changes after growing on different concentrations of heavy metals (CdCl2, CuCl2, Pb(NO3)2 and ZnCl2). Morphological parameters such as root length (RL), shoot length (SL), fresh weight (FW), dry weight (DW), dry weight % and leaf size (leaf area/length) have been examined in potted plants grown on soil, artificially contaminated with heavy metal. Bioaccumulations of non-supplied micronutrients (Cu, Fe, Mn and Zn) after treatment with heavy metals were also observed in these vegetables. On the basis of FW of whole plant (matured), threshold concentration for Cd in B. juncea, B. rapa, L. sativum, L. sativa and D. carota were ascertained to be as 2.75, 0.25, 3.22, 1.25 and 1.0 mg kg-1 DW, respectively; for Cu were 18, 17.75, 14.75, 17.25 and 10.75 mg kg-1 DW; for Pb to be 46.5, 34.5, 52.7, 81.0 and 31.5 mg kg-1 DW; and for Zn were 173.5, 192, 172.5, 93.0, and 55.5 mg kg-1, respectively. Among the studied vegetables, D. carota showed lowest accumulation of all heavy metals in roots and shoots. Highest accumulation of Cd was observed in the shoot of L. sativum; Pb in the root of B. rapa, Cu in both root and shoot of B. juncea and Zn in the shoot of B. rapa. Reduction in FW, SL and RL in B. rapa, L. sativa and D. carota have been recorded as symptoms of Cd toxicity; and reduction in FW and RL in B. juncea, B. rapa and L. sativa as symptom of Cu-toxicity. Similarly, reduction in FW in B. rapa, L. sativum and RL in B. rapa, D. carota have been observed as Pb-toxicity, reduction in FW and RL in B. juncea and B. rapa, and SL in B. rapa, L. sativum and L. sativa as symptoms of Zn- toxicity. Impact of different concentrations of CdCl2, CuCl2, Pb(NO3)2 and ZnCl2 on chlorophylls after the increased uptake of Cd, Cu, Pb and Zn in B. juncea, B. rapa, L. sativa, L. sativum and D. carota were studied. Significant loss of Chl–a, Chl-b and total chlorophyll were observed in B. juncea and L. sativum with depletion of Cu, Zn and/or Mn after increased Cd uptake. Significant loss in total-chl after increased Cu uptake was observed in B. juncea and D. carota with depletion of essential Zn, Fe (in B. juncea) and or Mn (in D. carota). Total chlorophyll increased significantly in B. juncea up to 500 mg Pb(NO3)2 kg-1 soil treatment but it decreased insignificantly in D. carota only at 1000 mg kg-1 soil treatment. There was moderate increased in Fe accumulation in all vegetables (except L. sativum) when grown on Pb(NO3)2 treated soil; but Zn, Cu and Mn depleted in D. carota grown on Pb(NO3)2 treatments. Insignificant change in chlorophyll was observed in Zn-treated vegetables. Present studies suggest that depletion of essential micronutrients like Zn and Fe; or Zn and Cu; or Fe and Mn in the plant body after heavy metal accumulation may be one of the causes for chlorophyll loss. Evaluation of heavy metal in soil and vegetables grown from agricultural fields of Kathmandu valley was conducted in the present study. Highest accumulations of Cd (2 mg kg-1), Cu (65.5 mg kg-1) and Pb (46.75 mg kg-1) from Shankhamul; Ni (29.25 mg kg-1) from Nakhu; Co (15.25 mg kg-1) and Mn (675 mg kg-1) from Balkhu; Cr (73.75 mg kg-1) from Banasthali, Zn (162 mg kg-1) and Fe (75636 mg kg-1) from Khusibun were recorded in soils of agricultural fields. On the basis of mean values, highest accumulation of Cu, Co and Zn were recorded in spinach and Pb in red radish; Ni, Cr and Fe were recorded in broad leaf mustard and Mn in cress leaf. Concentration of non –essential but toxic metal like Pb was higher than the normal plant value (0.1-10 mg kg-1) in all the vegetables (except potato) collected from different sampling sites. Potato accumulated fewer amounts of heavy metals among the others. As vegetables are one of the importance dietary items, it is cultivated widely in Kathmandu valley. The daily intake of heavy metals (Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb and Zn) via vegetables was estimated in the present study. Intake estimation was based on vegetables availability data and analysis of vegetables contaminants. The mean daily intake of potentially toxic metals ranged about 33.4 % (for Cd), 40.38 % (for Ni) and 251.6 % (for Pb) of the provisional tolerable daily intakes (PTDI) for adults. Vegetables were found to contribute significantly to the recommended daily intake of essential elements such as Cr (97.4-24.35 %), Cu (15.45-7.7 %), Fe (41 %), Mn (65.71-26.28 %), and Zn (21.23 %). To understand the phytoextraction of heavy metals from heavy metal contaminated soil, 18 different vegetable were grown on soil artificially contaminated with 300 mg CuCl2 kg-1, 500 mg Pb(NO3)2 kg-1, 800 mg ZnCl2 kg-1 or their mixed metal (1600 mg kg-1). From the single metal contaminated soil, lowest Cu accumulation was recorded in B. juncea and highest in V. faba; lowest Pb accumulation was recorded in S. tuberosum, and highest in A. fistulosum; and lowest Zn accumulation was recorded in A. fistulosum and S. tuberosum and highest in V. faba. From mixed metal soil treatments, lowest accumulation of Cu, Pb and Zn was recorded in B. juncea, B. caulorapa and A. fistulosum, respectively, and highest accumulation of Cu and Pb in S. oleracea (Deshi), and Zn in S. oleracea (Patane) was recorded. Remedial measures using cow dung and lime at different treatments showed that Cu and Pb accumulation in vegetables are higher in lime treatments than in 20 % cow dung treatments. Zinc accumulation increased in B. rapa and L. sativum in both cow dung and lime than in control. Among the tested vegetables for remedial measures, accumulation of Cu, Pb and Zn from mixed metal treatment was highest in L. sativum (treated with lime 9 g for Cu and Pb, and 20 % cow dung for Zn). Morphological changes such as FW, DW, SL and RL (except RL in B. rapa) increased significantly (P≤0.01) in all vegetables in Zn and cow dung treated soil, but not significant changes were observed with lime treatment. FW and DW increased only in L. sativum grown in 3 g lime treatment, whereas DW % increased significantly in B. rapa of both the doses of lime. Immobilization of Cu, Pb and Zn in both single and mixed metal treatments was found to be high in cow dung amended soil. But in single metal salts such as CuCl2 or Pb(NO3)2 and lime treated soil, the concentration of Cu and Pb retained in the soil was lower than in control, indicating their free mobility in the plants. From this it can be ascertained that 20 % cow dung treatment is suitable for immobilization of supplied metals than lime treatment.
Spatial distribution of vegetation composition and structure in Kailash Sacred Landscape, Nepal
(Institute of Science and Technology, Botany, 2022) Subedi, Chandra Kanta
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