Research on mangrove vegetation which have biological activities in Xuan thuy national park and propose sustainable usage

Mangroves are important to not only ecology but also socio-economic. Mangroves are considered as a center of tropical marine biology, one of the world’s most biodiversity and genetic ecosystems. About 90% of marine organisms live in mangroves, and 80% of the world’s fisheries depend on mangroves (S. Sandilyan, 2012). However, the mangrove ecosystem is vulnerable to human impacts and climate change. There have been several hitherto report that mangroves in the world are severely degraded (FAO, 2007). In an effort to protect this particularly valuable ecosystem, scientists have been researching in a variety of aspects in order to exploit, converse and develop these resources in a scientific and effective way. Vietnam, with more than 3,000 km of coastline, has a rich mangrove forest system stretching from north to south. Mangroves not only act as a major role in ensuring the livelihoods of the coastal residential but also play an extremely important role in ensuring environmentalism, reducing nature’s impacts and overcoming the phenomena of rising sea level, saline intrusion, etc. Xuan Thuy National Park, which belongs to the Northern mangrove system, is located in the southeast of Giao Thuy district, Nam Dinh province, at the Ba Lat estuary of the Red River. According to previously punlished documents, the total area of the park is approximately 7,100 hectares, including 3,100 hectares of land and roughly 4,000 hectares of mangrove forest. Xuan Thuy National Park is the 50th Ramsar Site of the World, the first of Southeast Asian and the only of Vietnam from 1989 to 2005. In accordance with the report of Xuan Thuy National Park, it is preserving the precious ecological value, such as thousands of hectares of mangroves, rich aquatic resources including algae which have economic value. The resources of Xuan Thuy National Park are likely to exploit bioactive substances, including: 1) Mangroves species; 2) Mollusca; 3) Botany that live in mangrove conditions; 4) Microalgae and microorganisms of mangroves. In particular, mangrove plants play the central role of the mangrove ecosystem. This biological resource has not been researched, exploited and used effectively, along with the risk of recession due to the impact of emphatic climate change and human activities. However, nowadays, there are insubstantial and comprehensive studies on mangrove plant in Xuan Thuy National Park towards biological activity have shown. To contribute to researches related to the mangrove system, the Ph.D. student conducted a research project “Research on mangrove vegetation which have biological activities in Xuan Thuy National Park and propose sustainable usage

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MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ----------------------------- PHAN THI THANH HUONG RESEARCH ON MANGROVE VEGETATION WHICH HAVE BIOLOGICAL ACTIVITIES IN XUAN THUY NATIONAL PARK AND PROPOSE SUSTAINABLE USAGE Major: Botany Code : 9 42 01 11 SUMMARY OF BIOLOGICAL DOCTORAL THESIS HANOI - 2018 This thesis was fulfilled at Graduate University of Science and Technology Supervisor 1: Assoc.Prof. Dr. Tran Huy Thai Supervisor 2: Dr. Nguyen Hoai Nam Reviewer 1: Assoc.Prof. Dr. Nguyen Trung Thanh Reviewer 2: Assoc.Prof. Dr. Trinh Thi Thuy Reviewer 3: Assoc.Prof. Dr. Nguyen Khac Khoi The thesis will be defended in the Graduate University of Science and Technology (GUST) council at Vietnam Academy of Science and Technology (VAST) at on.. 2018 This thesis may be found at: - The library of GUST - National Library of Vietnam 1 INTRODUCTION 1. The urgency of this dissertation Mangroves are important to not only ecology but also socio-economic. Mangroves are considered as a center of tropical marine biology, one of the world’s most biodiversity and genetic ecosystems. About 90% of marine organisms live in mangroves, and 80% of the world’s fisheries depend on mangroves (S. Sandilyan, 2012). However, the mangrove ecosystem is vulnerable to human impacts and climate change. There have been several hitherto report that mangroves in the world are severely degraded (FAO, 2007). In an effort to protect this particularly valuable ecosystem, scientists have been researching in a variety of aspects in order to exploit, converse and develop these resources in a scientific and effective way. Vietnam, with more than 3,000 km of coastline, has a rich mangrove forest system stretching from north to south. Mangroves not only act as a major role in ensuring the livelihoods of the coastal residential but also play an extremely important role in ensuring environmentalism, reducing nature’s impacts and overcoming the phenomena of rising sea level, saline intrusion, etc. Xuan Thuy National Park, which belongs to the Northern mangrove system, is located in the southeast of Giao Thuy district, Nam Dinh province, at the Ba Lat estuary of the Red River. According to previously punlished documents, the total area of the park is approximately 7,100 hectares, including 3,100 hectares of land and roughly 4,000 hectares of mangrove forest. Xuan Thuy National Park is the 50th Ramsar Site of the World, the first of Southeast Asian and the only of Vietnam from 1989 to 2005. In accordance with the report of Xuan Thuy National Park, it is preserving the precious ecological value, such as thousands of hectares of mangroves, rich aquatic resources including algae which have economic value. The resources of Xuan Thuy National Park are likely to exploit bioactive substances, including: 1) Mangroves species; 2) Mollusca; 3) Botany that live in mangrove conditions; 4) Microalgae and microorganisms of mangroves. In particular, mangrove plants play the central role of the mangrove ecosystem. This biological resource has not been researched, exploited and used effectively, along with the risk of recession due to the impact of emphatic climate change and human activities. However, nowadays, there are insubstantial and comprehensive studies on mangrove plant in Xuan Thuy National Park towards biological activity have shown. To contribute to researches related to the mangrove system, the Ph.D. student conducted a research project “Research on mangrove vegetation which have biological activities in Xuan Thuy National Park and propose sustainable usage” 2. The meaning of dissertation topic  Scientific significance This dissertation contributed to implement data on the diversification of vascular plants, structure, biomass of some typical mangrove vegetation communities, chemical compositions, and biological activities of mangrove vegetation in Xuan Thuy National Park.  Practical significance 2 Based on the results of the research, the thesis has selected mangrove species with biological activity and proposed sustainable use of some valuable medicinal species in order to conserve and develop mangrove plants in Xuan Thuy National Park 3. Structure of the dissertation The dissertation consists of 146 pages, including: Introduction (2 pages); Chapter 1: Overview (28 pages); Chapter 2: Subjects, scope, content and methods (14 pages); Chapter 3: Research result and discussion (83 pages); Chapter 4: Conclusion and request (3 pages); New contributions of the thesis (1 page); List of published works (1 page); Reference (14 pages). CHAPTER 1. OVERVIEW 1.1. Mangrove definition The term ‘mangrove’ cannot be definite in the exact way. Saeger’s definition of mangrove is a type of tall plant (trees, shrubs, herbs or ferns) which dominate in semi-tropical coastal tide, subtropical, showing a distinct level of tolerance to anaerobic conditions and high salinity, and blume can live in marine dispersal condition (P. Saenger, 2002). 1.2. Geographic distribution, mangrove area 1.2.1. Mangrove area and distribution in the world Mangrove is distributed mainly in the equatorial and tropical area of two hemispheres (between latitudes 23oN and 23oS), at coastline, island chains, warm Gulf Stream spreading offset from the abundant mangrove to cooler areas. Mangrove in the world is distributed in 124 countries and regions. Mangrove accounts for approximately 1 % of the world’s forest area and appear in about 75% of the tropical coasts of the world (P. Saenger, 2002). 1.2.2. Mangrove area and distribution in Vietnam According to Phan Nguyen Hong et al. (1999), mangroves in Vietnam are divided into four zones and 12 sub-zones: Zone I: Northeast Coast, from Ngoc headland to Do Son headland; Zone II: Northern Delta Coast, from Do Son headland to Lac Truong headland; Zone III: Central Coast, from Lach Truong headland to Vung Tau headland, Zone IV: South Coast, from Vung Tau headland to Nai headland, Ha Tien. 1.3. Value, role of mangrove Mangroves are important ecosystems that provide a variety of goods and services to the coastal citizens. The profit of mangrove includes timber and non-timber forest products, aquatic product resources, biofiltration, coastal protection, carbon storage and absorption, recreation and ecotourism. 1.4. Mangrove plants 1.4.1. Mangrove plants diversity in the world The total number of species of vegetation in the world is 23 genera and 53 species belonging to 16 families. According to Saenger et al. (1983), the total number of mangrove species is 60 species. The exact number of mangroves in the world so far has been debated and discussed among taxonomists. The official number of mangrove vegetative species ranging from 50 to 70 following the different classification systems. 1.4.2. Mangrove plants diversity in Vietnam 3 It can be said Phan Nguyen Hong, who has many monographs, articles on mangrove has been published, is a leading author in the study of mangroves in Vietnam. In 1993, Phan Nguyen Hong published the list of 77 species of mangroves in two groups divided into different environmental and life forms: Group 1, referred to as true mangrove, has 35 species belonging to 20 genera of 16 families; Group 2, has 42 species belonging to 36 genera of 28 families, including species live in mangrove, which usually grow in secondary and planted forests on high ground. Nowadays, there are 69 mangrove species in the South, and 34 species in the North. 1.5. Structure, biomass of true mangrove vegetative communities in Xuan Thuy National Park The study of the structural and biomass characteristics of plant communities, especially mangrove communities is very important. The results of this research help researchers understand the ecological succession of biome, assess the natural reserves which is the basis for effective management and exploitation of vegetative resources. Normally, studies on mangrove structure and biomass are conducted in parallel. 1.6. Research on the chemistry and biological activity of mangrove plants 1.6.1. Research on the chemistry of mangrove plants 1.6.1.1. Research situation in the world These days, there are more than 40 plant species have been chemically studied, 349 compounds have been isolated from mangrove plants and 200 compounds from semi- mangrove plants, in which 200 secondary metabolite compounds are reported to be present in only real mangrove species, and 80 compounds are found only in semi-mangrove plants, LP Jayatissa et al., 2006. 1.6.1.2. Research situation in Vietnam In Vietnam, the research on the chemical composition of mangrove species is quite poor and not really comprehensive. Nguyen Thi Hoai Thu et al. studied the chemical composition of Sonneratia alba collected in Can Gio Mangrove. The results showed that six compounds are isolated from petroleum ether fraction of leaves of Sonneratia alba including oleanolic acid, betulin, betulinic acid, alphitolic acid, methyl gallate and 5- hydroxymethylfurfural (Nguyen Thi Hoai Thu et al. 2011). 1.6.2. Research on biological activity of mangrove plants 1.6.2.1. Researches in the world Mangrove forests are rich in chemical compounds such as steroids, triterpenes, saponins, flavonoids, alkaloids and tannins. Extracts from mangrove species are thought to have a variety of medicinal properties. Studies on biological activity have shown that mangrove plant species have antimicrobial activity, antioxidant, cytotoxic, anti-cancer, anti-fungal, antimalarial and antimicrobial activity assay. 1.6.2.2. Researches in Vietnam As well as studies on the chemical composition, studies on the biological activity of mangrove species in Vietnam are few and far from comprehensive. 4 Pham Van Ngot et al. studied on the antimicrobial activity of some mangrove species in Can Gio Mangrove Biosphere Reserve. The results show that the methanol fraction from 10 species of mangrove: S. alba, D. trifoliate, L. racemosa, R. apiculata, R. mucronata, Pluchea indica (L.) Lees., Dolichandrone spathacea (L.f.) Seem., Wedelia biflora (L.) DC., B. gymnorhiza, X. granatum are resistant to pathogens such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa (Pham Van Ngot et al., 2015) CHAPTER 2. SUBJECTS, CONTENTS AND RESEARCH METHODS 2.1. Subjects and research scope The study subjects are tracheophyta vascular plants and some mangrove floristic composition conditions in high tide and sand dunes in the core and buffer zone of Xuan Thuy National Park. Plant species in agricultural ecosystem, artificial ecosystems are not mentioned in this study - Study period: 3 years: 2014 - 2016. 2.2. Research contents - Research diversity in vascular plants at Xuan Thuy National Park, Nam Dinh. + Definition of scientific name, establish vascular plants species list. + Diversity in vascular plants taxon-level at Xuan Thuy National Park. + Diversity of life forms, botanical geography. + Assess value in use of plants species. + Rare species plants have conservation value. - Research on structure, biomass from a few feature plants communities in Xuan Thuy National Park. - Sampling, bioactivity screening of some mangrove for the next study. - Research on chemical constituents and biological activity of Sonneratia caseolaris (L.) Engl. and Rhizophora stylosa Griff. from Xuan Thuy National Park. - Propose sustainable usage on mangrove vegetation which have biological activities in Xuan Thuy National Park. 2.3. Research methods 2.3.1. Research methods of diversity in vascular plants 2.3.1.1. Methods of inheritance 2.3.1.2. Methods of plants investigation by routes Research methods of diversity in plants using scientific documents of N.N.Thin (1997, 2004 ) combined results from the study of the world’s research. 2.3.1.3. Analysis of collected information and data a) Definition of scientific name, establish plants species list. Definition of scientific name: The scientific names of mangrove species was determined by morphological comparison methods. The main documents used are FAO (1994), Vietnamese Herbs (P.H.Ho, 1999-2000), List of Vietnamese Plants (Nguyen Hoang Tri, 1996). Establish plants species list based on the system opinion A.L.Takhtazan (1973), N.T.Ban (2003, 2005) for the branches and classes. Families and species in families are arranged in alphabetical order of the scientific names (Brummit, 1992). 5 b) Diversity assessment in plants taxon-level Assessment of diversity in plants at the level of branches and classes: Statistics of number of families, genera, species with each branches, classes, families and genera. Identify genera index (species average number of a genera), families index (species average number of a families), and genera/families index as the average genera per families. Assess the diversity in a species in families and genera: Statistics of 10 families and 10 genera to determine the diversity in a species in families and genera. c) Diversity assessment in plant life-form The plant life-form is determined by Raunkiaer system (1934). d) Diversity assessment in botanical geography Based on the distribution of species in the world and Vietnam to identify botanical geography factors according to Pocs Tamas, 1965 and Le Tran Chan, 1999. e) Assessment value in use of plants species The value in use of plant species is determined by the following key documents: Vietnam Forest Tree Name (Ministry of agriculture and rural development, 2000), 1900 useful plant species in Vietnam (T.D. Ly, 1993), Useful plants in Vietnam (V.V. Chi & Tran Hop, 1999). Vietnamese medicinal plants and herbs (D.T. Loi, 1995), Dictionary of medicinal plants in Vietnam (V.V. Chi, 2012), Vietnam Plant Resources (T.M. Hoi, 2013) And based on the study that gathered by local usage experiences. f) Assessment of the conservation value of plants Vietnam Red Book (2007), Decree 32/2006 / ND-CP (2006) of the Government. 2.3.2. Research methods of the structure of mangrove plants communities 2.3.2.1. Field research methods Methods of vegetation research based on the method of plants research by Nguyen Nghia Thin (2007). 2.3.2.2. Methods of analysis information, data processing. Summarize all data collected from the phase report, measurement at plot to calculate, analyze and process data. Data is processed and analyzed by Microsoft Excel 2007. Determine biomass of species in plant communities according to the formula of Komiyama (2005). 2.2.3. Methods of chemical research and biological activity 2.3.3.1. Methods of isolation of compounds a) Thin layer chromatography (TLC) b) Preparative thin layer chromatography (Prep TLC) c) Column chromatography (CC) 2.3.3.2. Methods of determining the structure of compounds The general method for determining the chemical structure of compounds is to combine the determination of physical properties with modern spectroscopic methods including: a) Mass spectrometry (ESI-MS) b) Nuclear Magnetic Resonance Spectrum (NMR) c) Melting point (Mp) 6 2.3.3.3. Methods of biological activity research a) Evaluation of antimicrobial activity assay Antimicrobial activity assay: evaluatation of the antibiotic activity of the fractions proceeded on 96 well microtiter plates by methods Vander Bergher and Vlietlinck (1991) and McKane & Kandel (1996). b) Evaluation of cytotoxic activity assay The in vitro cytotoxicity assay was approved by the National Cancer Institute (NCI) as the standard cytotoxicity test for screening, detecting compounds that inhibit growth or kill cancer cells. This test is performed according to the method of Monks (1991). CHAPTER 3. RESEARCH RESULTS AND DISCUSSION 3.1. Diversity in vascular plants at Xuan Thuy National Park 3.1.1. Definition of scientific name, establish plants species list. Based on the collected samples, the scientific name has been determined and established vascular plants species list. According to the results, Xuan Thuy National Park has recorded 116 species (including mangrove plants, species involved in mangroves, species from inland and adapted to Xuan Thuy National Park) belonging to 101 genera, 42 families of Pteridophyta and Magnoliophyta. Magnoliophyta is divided into two classes: Magnoliopsida include 32 families, 73 genera, 112 species, Liliopsida include 5 families, 21 genera, 26 species of vascular plants. Xuan Thuy National Park has 18 mangrove plants, 88 species involved in mangroves, 10 species from coastal inland. 3.1.2. Diversity in plants in the Xuan Thuy National Park 3.1.2.1. Diversity in branches Diversity in branches at Xuan Thuy National Park has only 2 branches and very different in number of species. Magnoliophyta has 109 species, 93.97% of total species; 94 genera, 93.07% of total genera and 37 families, 88.1% of total families in the study area. Families and genera of Magnoliophyta have a high percentage compared to the rest. Polypodiophyta, only 7 species, has 6.03% of total species; 7 genera, 6.93% of total genera and 5 families, 11.9% of total families in the study area. Diversity index of families, genera and average diversity index genera and families: - Diversity index of families is 2.76 - Diversity index of genera is 1.15 - Average diversity index genera and families is 2.4 3.1.2.2. Diversity in families Of the 42 vascular plants branches at Xuan Thuy National Park, 20 families has only one species; 10 families has 2 species and 2 families has 3 species. There are 32 families has the least number of species. The 10 most diverse families are from 4 to 15 species, including one family have 15 species (Poaceae), followed by a family of 14 species (Asteraceae), a family of 9 species (Verbenaceae), a family of 6 species (Cyperaceae), two families of five species (Rhizophoraceae, Malvaceae) and four families of four species (Amaranthaceae, Euphorbiaceae, Fabaceae, Solanaceae). 3.1.2.3. Diversity in genera 7 Plants at Xuan Thuy National Park has 10 large families (9.9%) with 24 species (23.76%). The most abundant species are Cyperus with 4 species (3.96%); Bruguiera and Sonneratia has 3 species (2.97%); the remaining 7 genera are Acanthus, Achyranthes, Pluchea, Solanum, Vitex, Pandanus and Paspalum has 2 species (1.98%). 3.1.3. Diversity of life forms In Xuan Thuy National Park, 115 species (99.13% of total species) have been identified, one species has not been identified. Of the species identified, the upper shoot group (Ph) was dominant with 66 species (55.65%); followed by group of trees near the soil (Ch) has 17 species (14.78%), group of trees a year (Th) has 17 species (14.78%); group of hidden- shot tree (Cr) has 9 species (7.82%) and semi-hollowed tree (Hm) has 8 species (6.95%) were the lowest. Set up a live spectrum for plants at Xuan Thuy National Park as follows: SB = 55.65 Ph + 14.78 Ch + 6.95 Hm + 7.82 Cr + 14.78 Th So the upper shoot group (Ph) has the largest number of species, playing a dominant role in comparison to other life forms. Group Ph spectrum as follows: Ph = 7.25 Mg + 10.93 Me + 4.69 Mi + 46.87 Na + 12.5 Lp + 18.75 Hp 3.1.4. Diversity of botanical geography Botanical geography factors of 113 plant species (97.41%) have been identified, while 3 species have not identified (2.59%). Among the botanical geography factors of Xuan Thuy National Park, the Asia tropical factors is the highest proportion (32.76%); followed by new- tropical and inter-tropical factors has 16.38%; Indoch