Search

Mangroves on the islands along the Java Sea play a crucial role in supporting biodiversity, protecting coastlines, and sequestering carbon. However, there is a lack of information on mangrove structure and biomass in the area. This study aimed to assess the mangrove structures and biomass on Desa Daun, located on the Bawean Islands, and Kemujan Island, located on the Karimunjawa Islands, respectively. The study utilized a combination of line transect and quadrant plot methods with a size plot of 10x10 m. We established 7 line transects and 28 quadrant plots in the mangrove forest of Desa Daun and similarly set up 7 line transects and 21 quadrant plots on Kemujan Island. Within each quadrant, the mangrove species were identified, and their diameters at breast height (DBH) were recorded. To assess the relative significance of each species, the importance value index (IVI) was calculated, and allometric equations were applied to estimate biomass and carbon storage in the trees. PlanetScope imagery was also used to quantify the carbon stock of mangroves on those islands. In Desa Daun, 13 mangrove species were identified, while 12 species were recorded on Kemujan Island. The species Nypa fruticans and Excoecaria agallocha exhibited the highest IVI in Desa Daun and Kemujan Island, respectively. Notably, Rhizophora apiculata demonstrated the greatest biomass in both locations, with measurements of 43.08 Mg B/ha in Desa Daun and 102.22 Mg B/ha in Kemujan Island. Overall, mangrove stands on Desa Daun stored biomass of 113.60 Mg B/ha and carbon of 50.98 Mg C/ha, whereas mangrove stands on Kemujan Island stored biomass of 295.04 Mg B/ha and carbon of 131.95 Mg C/ha. Mangrove stands of the whole Bawean Islands sequestered 22,941 Mg C, while Karimunjawa Islands hold much higher C stocks, 79,451 Mg C. Despite being smaller in size, the Karimunjawa Islands have more extensive mangrove coverage compared to the Bawean Islands due to their geomorphological characteristics, which in turn influence their mangrove structures and carbon stocks. However, the loss of mangroves in the Karimunjawa Islands due to aquaculture expansions could increase carbon loss in the islands. [ABSTRACT FROM AUTHOR]

Mangrove ecosystems are crucial for biodiversity and coastal protection but face threats from climate change and human activities. This review assesses the productivity of the Matang Mangrove Forest Reserve (MMFR) in Malaysia, which is recognised as one of the best-managed mangrove forests, while also addressing challenges such as deforestation and climate change-induced factors. This review explores the concept of productivity in mangrove forests, highlighting their role in carbon sequestration and discussing litterfall measurements as fundamental metrics for assessing primary productivity. An analysis of historical changes in MMFR's biomass and productivity revealed fluctuations influenced by logging, reforestation, and climatic conditions. Trends in MMFR productivity indicate a concerning decline attributed to anthropogenic activities such as aquaculture and industrial projects. A regression analysis conducted on Rhizophora apiculata data with age as the predictor and AGB as the response variable indicated a positive trend (slope = 3.61, R-squared = 0.686), suggesting a quantitative increase in AGB with age. Further analysis revealed a significant negative trend in MMFR's overall productivity over years (coefficient = −3.974, p < 0.05) with a strong inverse relationship (rho = −0.818, p < 0.05), indicating declining AGB trends. Despite these challenges, this review underscores the significance of sustainable management practices, effective conservation efforts, and community engagement in maintaining mangrove ecosystem health and productivity. In conclusion, sharing management lessons from MMFR can contribute to global conservation and sustainable mangrove forest management efforts, fostering resilience in these vital ecosystems. [ABSTRACT FROM AUTHOR]

Mangroves on the islands along the Java Sea play a crucial role in supporting biodiversity, protecting coastlines, and sequestering carbon. However, there is a lack of information on mangrove structure and biomass in the area. This study aimed to assess the mangrove structures and biomass on Desa Daun, located on the Bawean Islands, and Kemujan Island, located on the Karimunjawa Islands, respectively. The study utilized a combination of line transect and quadrant plot methods with a size plot of 10x10 m. We established 7 line transects and 28 quadrant plots in the mangrove forest of Desa Daun and similarly set up 7 line transects and 21 quadrant plots on Kemujan Island. Within each quadrant, the mangrove species were identified, and their diameters at breast height (DBH) were recorded. To assess the relative significance of each species, the importance value index (IVI) was calculated, and allometric equations were applied to estimate biomass and carbon storage in the trees. PlanetScope imagery was also used to quantify the carbon stock of mangroves on those islands. In Desa Daun, 13 mangrove species were identified, while 12 species were recorded on Kemujan Island. The species Nypa fruticans and Excoecaria agallocha exhibited the highest IVI in Desa Daun and Kemujan Island, respectively. Notably, Rhizophora apiculata demonstrated the greatest biomass in both locations, with measurements of 43.08 Mg B/ha in Desa Daun and 102.22 Mg B/ha in Kemujan Island. Overall, mangrove stands on Desa Daun stored biomass of 113.60 Mg B/ha and carbon of 50.98 Mg C/ha, whereas mangrove stands on Kemujan Island stored biomass of 295.04 Mg B/ha and carbon of 131.95 Mg C/ha. Mangrove stands of the whole Bawean Islands sequestered 22,941 Mg C, while Karimunjawa Islands hold much higher C stocks, 79,451 Mg C. Despite being smaller in size, the Karimunjawa Islands have more extensive mangrove coverage compared to the Bawean Islands due to their geomorphological characteristics, which in turn influence their mangrove structures and carbon stocks. However, the loss of mangroves in the Karimunjawa Islands due to aquaculture expansions could increase carbon loss in the islands.

Mangroves are unique ecosystems. As they are present in a transition zone, they harbour a variety of organisms, which include microorganisms, aquatic as well as terrestrial organisms. Being present in an ever-changing and adverse environment, mangroves have developed several adaptations that make them unique. These unique features have been exploited for the isolation of various useful compounds from mangroves. The organisms associated with the mangrove ecosystem will also be well equipped to survive such extreme conditions. Microorganisms such as bacteria, fungi, actinomycetes, algae etc, survive in this changing environment, and they might be producing certain metabolites as a part of their survival mechanism, which can be exploited for the production of various compounds that are useful to mankind. Mangrove microorganisms can be used as an important source of food, medicines, enzymes, antimicrobials etc. [ABSTRACT FROM AUTHOR]

Seedlings of two species of mangroves, Bruguiera gymnorrhiza and Rhizophora apiculata, were monitored for 8 years on the Pacific island of Kosrae, Federated States of Micronesia, to determine the effects of canopy cover and hydrogeomorphic zone on long-term survival and growth. Annual rainfall is high with little seasonality. Study plots with seedling subplots were in fringe, riverine, and interior hydrogeomorphic zones along four small rivers. The height of each seedling was measured each year and was designated each time as being under an open, partially closed, or closed canopy. Growth rates of both species were slow, and no seedling that was newly established during the study became a sapling (2 m). Many seedlings stopped growing for long periods of time. Bruguiera seedlings were more numerous than Rhizophora seedlings. They grew faster than Rhizophora seedlings except in riverine zones. Predicted growth rates of Bruguiera were fastest under an open canopy and slowest under a closed canopy, but Rhizophora was not affected by canopy status. Overall mortality rates for the two species were similar, averaging 36% year−1. El-Niño-Southern Oscillation events did not affect growth or mortality but may have caused some defoliation. [ABSTRACT FROM AUTHOR]

Environmental pollution and climate change have been reported to severely affect the growth and productivity of mangroves. However, it is still unclear how the mangroves will fare if stressed by these adverse conditions, and how the mangroves might fare if these conditions improve. In this study, the trends of mangrove forests in the Thi Vai catchment (Vietnam) were assessed using mathematical models, addressing the polluted environment under climate change conditions. This simulated study was conducted based on the analysis of different types of data. Data on 18 elements' concentrations accumulated in mangrove tissues in this catchment were analyzed in relation to the states of tree growth rates. Data on the economic productivity and water quality of the Thi Vai River in the five years from 2017 to 2021 were analyzed to detect the main sources of pollution that induced damage to mangrove forests. The results achieved from data analysis are the linear and nonlinear interactions between the concentrations of tissue-accumulated substances and the growth rates of trees. Concentrations of P, Mg, and Sr in mangrove leaves have a linear relationship with plant growth while Cr, Cu, and Ni accumulated in roots have a nonlinear relationship. The mining industry and accommodation and food services are the main contributing sources of Cr and Cu, which affect mangrove health. Information supplied from the data analysis helped in designing the scenarios of different combined environmental conditions for model simulations. Our previously developed mangrove dynamics model was applied to predict the trajectory of the mangrove forest in this area under a total of 16 combined environmental condition scenarios. [ABSTRACT FROM AUTHOR]

Aims: Dengue virus is a global pathogen that lacks an effective vaccine or therapy. Screening medicinal plants for antidengue properties provides a promising avenue to identify potent compounds. Mangroves, known for their resilience in harsh conditions, produce a diverse range of natural products with unique biochemical profiles, which hold potential for anti-dengue treatments. This study aims to evaluate the anti-dengue activity of selected mangrove plant species from Sabah against DENV2 NS2B-NS3pro, utilizing an enzymatic protease assay. Methodology and results: Six mangrove species (Avicennia marina, Bruguiera gymnorrhiza, Ceriops tagal, Rhizophora apiculata, Rhizophora mucronata and Xylocarpus granatum) were investigated, with various plant parts subjected to aqueous and ethanol extraction. The results demonstrated significant anti-dengue activity in both aqueous and ethanolic extracts of the mangroves against DENV2 NS2B-NS3pro, with IC50 values ranging from 0.95 µg/mL to 6.24 µg/mL. Notably, the ethanolic extract of R. apiculata leaves exhibited the highest inhibition, with an IC50 value of 0.95 µg/mL. Conclusion, significance and impact of study: These findings suggest that the ethanolic extracts from R. apiculata leaves hold promise as potential candidates for dengue treatment. This study underscores the importance of natural products as valuable sources for the development of novel anti-dengue treatments, highlighting the need to explore mangroves in the quest for effective therapeutic options. [ABSTRACT FROM AUTHOR]

An attempt made to isolate the mangrove endophytes from Rhizophora apiculata, Nypa fruticans, and Xylocarpus granatum has shown the presence of about 28 different strains of endophytic fungi belonging to the phyla Ascomycota. Rhizophora apiculata was found to possess highly diverse endophytic species compared to Nypa fruticans and Xylocarpus granatum. Furthermore, the leaves of the mangrove trees were found to serve as a rich source of endophytic fungal species compared to other segments studied. Moreover, it was observed that the leaf acted as a major source of endophytic fungi in Rhizophora apiculata and Nypa fruticans, whereas barks were found to have a high number of species in Xylocarpus granatum. [ABSTRACT FROM AUTHOR]

A mangrove plant known as Rhizophora apiculata is employed by Malay for treating skin diseases, diarrhea, vomiting, and nausea, as an antiseptic, for tanning, and also as fuelwood and fodder. Its large-scale use can be attributed to its high-quality timber, availability as well and the presence of a chemical named tannin that is employed for reinforcing fishing lines, nets, and ropes. The tannin content of R. apiculata's roots, bark, and leaves is regarded to be a natural inhibitor of fungal infections. This study is focused on determining the different kinds of functional groups, as well as individual phenolic compounds present in R. apiculata for identifying new bioactive compounds via decoding of the traditional values of Malay remedies. There is a high demand for such natural bioactive compounds, particularly in the healthcare and pharmaceutical markets. Alkaline fractional extracts were employed to design an analytical extraction method for R. apiculata. As per the HPLC results, there were three phenolic acids detected namely Caffeic acid, 4-Hydroxybenzoic acid, and Vanillic acid. Meanwhile, ten volatile compounds were identified by the GCTOF-MS. With regards to antibacterial activity, S. aureus, S. epidermidis, and E. coli were inhibited by R. apiculata leaf extract, while C. albicans and Fusarium sp. were inhibited by their antifungal activity. [ABSTRACT FROM AUTHOR]

Mangrove ecosystems are crucial for biodiversity and coastal protection but face threats from climate change and human activities. This review assesses the productivity of the Matang Mangrove Forest Reserve (MMFR) in Malaysia, which is recognised as one of the best-managed mangrove forests, while also addressing challenges such as deforestation and climate change-induced factors. This review explores the concept of productivity in mangrove forests, highlighting their role in carbon sequestration and discussing litterfall measurements as fundamental metrics for assessing primary productivity. An analysis of historical changes in MMFR’s biomass and productivity revealed fluctuations influenced by logging, reforestation, and climatic conditions. Trends in MMFR productivity indicate a concerning decline attributed to anthropogenic activities such as aquaculture and industrial projects. A regression analysis conducted on Rhizophora apiculata data with age as the predictor and AGB as the response variable indicated a positive trend (slope = 3.61, R-squared = 0.686), suggesting a quantitative increase in AGB with age. Further analysis revealed a significant negative trend in MMFR’s overall productivity over years (coefficient = −3.974, p < 0.05) with a strong inverse relationship (rho = −0.818, p < 0.05), indicating declining AGB trends. Despite these challenges, this review underscores the significance of sustainable management practices, effective conservation efforts, and community engagement in maintaining mangrove ecosystem health and productivity. In conclusion, sharing management lessons from MMFR can contribute to global conservation and sustainable mangrove forest management efforts, fostering resilience in these vital ecosystems.

Multidrug and Toxic Compound Extrusion (MATE) proteins are essential transporters that extrude metabolites and participate in plant development and cellular detoxification. MATE transporters, which play crucial roles in the survival of mangrove plants under highly challenged environments, by specialized salt extrusion mechanisms, are mined from their genomes and reported here for the first time. Through homology search and domain prediction in the genome assemblies of Avicennia marina, Bruguiera sexangula, Ceriops zippeliana, Kandelia obovata, Rhizophora apiculata and Ceriops tagal, 74, 68, 66, 66, 63 and 64 MATE proteins, respectively were identified. The phylogenetic analysis divided the identified proteins into five major clusters and following the clustering pattern of the functionally characterized proteins, functions of the transporters in each cluster were predicted. Amino acid sequences, exon-intron structure, motif details and subcellular localization pattern for all the 401 proteins are described. The custom designed repeat masking libraries generated for each of these genomes, which will be of extensive use for the researchers worldwide, are also provided in this paper. This is the first study on the MATE genes in mangroves and the results provide comprehensive information on the molecular mechanisms enabling the survival of mangroves under hostile conditions. [ABSTRACT FROM AUTHOR]

A field survey of synchronized fireflies (Pteroptyx tener Olivier) was conducted in Kuala Sepetang, Perak. It involved sampling efforts for six months, from November 2021 to April 2022. A total of 10 sampling stations were selected along 5.63 km from the upstream to the downstream of the river. A sweep net was used for sampling at each station, and the net was swept for two minutes. Such sampling was replicated twice at each station. At the same time, collecting vegetation samples was done by taking the leaves, flowers, fruits, tree trunks, and roots. For species identification, collected specimens were taken to the Laboratory of the School of Biological Sciences, Universiti Sains Malaysia (USM). From this survey, a total of 111,622 individuals were recorded. This species has been observed on Rhizophora mucronata, Rhizophora apiculata, and Sonneratia caseolaris. The distribution and abundance of fireflies in the sampling area were undocumented prior to this study. This study is being conducted to understand Pteroptys tener’s distribution in Malaysia better and to add knowledge about the undocumented area of Kuala Sepetang. By adding an undocumented location for this species, this study can contribute to and expand the knowledge of the distribution and occurrence of fireflies in Malaysia, particularly in Perak. [ABSTRACT FROM AUTHOR]

As a productive ecosystem component, mangroves provide critical services to humankind. Mangroves may be a source of antibacterial compounds that could be used as a natural treatment for managing bacterial infections. This study determined the phytochemical constituents of leaf extracts of three selected mangrove species Avicennia marina (Bungalon), Rhizophora apiculata (Bakhaw), and Sonneratia alba (Pagatpat), using the Test-tube Method and antibacterial sensitivity using an Agar Well-Diffusion Method found in the coastal areas of Talisay City, Negros Occidental, Philippines. The results showed that the three species of mangroves leaf methanolic extracts exhibit susceptibility to antibacterial properties against S. aureus; it was observed that S. alba has the highest inhibitory effect on S. aureus among the three selected mangrove species. There was a significant difference between the positive control (Linezolid 30 mcg) and the methanolic crude extract of R. apiculata (MD = 27.97, p < 0.01), A. marina (MD = 24.37, p < 0.01), and S. alba (MD = 23.09, p < 0.01). On the contrary, A. marina and S. alba did not differ significantly with p= 0.172; this means that the antibacterial activity of methanolic crude extracts of A. marina and S. alba are comparable but significantly differ with the positive control (Linezolid 30 mcg). The qualitative phytochemical analyses of the three species of mangroves' leaf methanolic extracts showed flavonoids, phenols, saponins, and tannins. Terpenoids were present only on R. apiculata.

Mangrove forest in Lubuk Kertang Village, West Brandan sub-district has been converted around 20 ha annually (1996–2016) into various non-forest land use. Rehabilitation can be a solution to restore the condition of the ecosystem so that it can resume its ecological and economic functions. This paper discusses the evaluation of mangrove rehabilitation carried out by planting 6000 propagules in December 2015 and 5000 seedlings in May 2016 with Rhizophora apiculata species in abandoned ponds. Monitoring was carried out every 6 months from 2016 to 2022. In the restored area, 11 true mangrove species and 3 associated mangrove species were found. The percentage of plants that survived after seven years was 69.42% for planting using propagules and 86.38% for planting with seedlings. The total biomass carbon stocks stored by 7-year-old plants using propagules was 51.18 Mg ha−1, while the carbon stored by planting using seedlings was 56.79 Mg ha−1. Soil carbon stocks at the planted site with propagules were 506.89 ± 250.74 MgC ha−1, and at the planted site with seedlings were 461.85 ± 102.23 MgC ha−1. The total ecosystem carbon stocks (including aboveground carbon) in the planted site using propagules were 558.07 MgC ha−1, while planting using seedlings were 518.64 MgC ha−1. The dataset and findings on the carbon storage evaluation of mangrove rehabilitation will be useful for blue carbon research community and policymakers in the context of the climate change mitigation strategy for Indonesia. [ABSTRACT FROM AUTHOR]

Mangrove productivity depends on the storage of nutrients and elements. Elemental concentrations were examined in leaves, roots, and sediments for three age stands (15, 25 years, and VJR) of Rhizophora apiculata in the Matang Mangrove Forest Reserve (MMFR). Six compartments with two compartments each for each age group were used to analyze sixteen elements. Four types of elemental patterns were examined with decreasing order during analysis: (1) Cd < Cu < Pb < Zn < Mg < Mn < Fe < K < Na < Ca and P% < S% < N% < C% in leaves, (2) Cd < Pb < Cu < Zn < Mg < Mn < Fe < K < Na < Ca and P% < S% < N% < C% in roots, (3) Cd < Pb < Cu < Zn < Mg < Mn < K < Fe < Na < Ca and P% < N% < S% < C% in sediment samples and (4) Cd(S) < Pb(S) < Cu(S) < Zn(S) < Mg(S) < Mn(L) < K(L) < Fe(S) < Na(R) < Ca(R) and P%(S) < S%(S) < N%(L) < C%(R) collectively for all samples. Evidence that elements do not store primarily in above-ground biomass can be found in the observation that elements are stored more in sediment and roots. The outcome of the present study shows that the rate of increase of elements in trees (leaves and roots) was less as compared to sediments, where the elemental concentration increased considerably with time. Elemental concentration comparison within three age classes showed that C, N, and S were significantly different in all three types of samples. The δ15N ratios showed positive values in all six compartments which supported the concept that the δ15N ratio could not be observed in N concentration in this study. The δ13C values showed more negative values in all six compartments which represented less salinity and a freshwater intake. The S, P, and heavy metals concentrations were high. The concentrations of Cd, P, N, C, and S in the sediment influenced variations in four compartments in accordance with the three mangrove age groups. The results of this study can be utilized to create management plans for MMFR and conduct risk assessments of the elements' concentration in sediment. [ABSTRACT FROM AUTHOR]

Mangrove is a species of high-level plant whose growth is influenced by the tides of seawater. Antifouling is a system used to prevent marine life attached to an object that is submerged in seawater. The use of natural Antifouling is one of the efforts to reduce water and environmental pollution, such as natural Antifouling from the mangrove plants Rhizophora apiculata and Avicennia alba. The study was conducted in Sungsang, South Sumatera, Indonesia. Avicennia marina and Rhizophora apiculata are mangrove plants that are suspected to have Antifouling content, namely tannins, terpenoids, and steroids. This research aims to determine the effect of the addition of the Avicennia marina fraction and the Rhizophora apiculata fraction on oil paints on the area of macrofouling pasting on the test plate, how the effect of adding different Avicennia marina fractions on the sticking of macrofouling on the wood plate. Avicennia marina and Rhizophora apiculata contain secondary metabolite compounds as natural Antifouling that do not pollute the environment and meet the H0 hypothesis rejected and H1 accepted and suspected that there is no macrofouling on the plates that have been tested proven to reduce pasting.

Simple Summary: We utilized the 10× Genomics technology to obtain a reference whole-genome sequence for assessing the genetic diversity and population structure of Rhizophora apiculata in Thailand. Using SNPs identified from the R. apiculata genome sequence, moderate genetic diversity and high genetic differentiation were observed among 82 R. apiculata accessions collected along the coasts of Thailand. Two subpopulations corresponding to the Gulf of Thailand and the Andaman Sea coasts were clustered and confirmed from three approaches: population structure, PCA, and phylogenetic analyses. The AMOVA result revealed that the percentage of variation within populations (76%) was higher than that among populations (24%). Rhizophora apiculata is one of the most widespread and economically important mangrove trees in the Indo-West Pacific region. Knowledge of the genetic variation of R. apiculata in Thailand is limited. Here, we generated a whole-genome sequence of R. apiculata using the 10× Genomics technology. R. apiculata genome assembly was 230.47 Mb. Based on its genome, 2640 loci of high-quality biallelic SNPs were identified from 82 R. apiculata accessions collected from 17 natural mangrove forests in Thailand to assess the genetic diversity and population structure among them. A moderate level of genetic diversity of R. apiculata was observed. The average observed heterozygosity (Ho = 0.48) was higher than the average expected heterozygosity (He = 0.36). Two subpopulations were observed and confirmed from three approaches: population structure, PCA, and phylogenetic analyses. They corresponded to the Gulf of Thailand and the Andaman Sea separated by the Malay Peninsula. AMOVA analyses indicated that genetic variation was attributable to 76.22% within populations and 23.78% among populations. A high level of genetic differentiation between the two subpopulations (FST = 0.24, p < 0.001) was observed. This study evaluated the genetic diversity and population structure of R. apiculata, providing useful information for sustainable mangrove management in Thailand. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two new and twenty-one known compounds were isolated from R. apiculata leaves. • The structures were elucidated by spectroscopic methods and computational studies. • All isolated compounds were evaluated for their cytotoxicity. One new 8,4'-oxyneolignan (1) and one new 7,8-dihydrobenzofuranone (2), together with twenty-one known compounds (3 ‒ 23) were isolated from the methanol extract of Rhizophora apiculata leaves. The structures of new compounds, as well as their absolute configuration, were determined by a combination of spectroscopic methods and quantum chemical calculations of NMR and ECD data. All isolated compounds were evaluated for their cytotoxicity, and only 2,6-dimethoxy-1,4-benzoquinone (8) exhibited inhibitory effects against SK-LU-1, HepG2, and MCF7 cells with IC 50 values in the range of 8.33–14.82 μ M. [ABSTRACT FROM AUTHOR]

In this study, 16S high-throughput and metagenomic sequencing analyses were employed to explore the changes in microbial community and function with the succession of mangroves (Sonneratia alba , Rhizophora apiculata , and Bruguiera parviflora) along the Merbok river estuary in Malaysia. The sediments of the three mangroves harbored their own unique dominant microbial taxa, whereas R. apiculata exhibited the highest microbial diversity. In general, Gammaproteobacteria, Actinobacteria, Alphaproteobacteria, Deltaproteobacteria, and Anaerolineae were the dominant microbial classes, but their abundances varied significantly among the three mangroves. Principal coordinates and redundancy analyses revealed that the specificity of the microbial community was highly correlated with mangrove populations and environmental factors. The results further showed that R. apiculata exhibited the highest carbon-related metabolism, coinciding with the highest organic carbon and microbial diversity. In addition, specific microbial taxa, such as Desulfobacterales and Rhizobiales, contributed the highest functional activities related to carbon metabolism, prokaryote carbon fixation, and methane metabolism. The present results provide a comprehensive understanding of the adaptations and functions of microbes in relation to environmental transition and mangrove succession in intertidal regions. High microbial diversity and carbon metabolism in R. apiculata might in turn facilitate and maintain the formation of climax mangroves in the middle region of the Merbok river estuary. [ABSTRACT FROM AUTHOR]

Tomato (Lycopersicon esculentum Mill.) is one of the most remunerative and widely grown vegetables in the world. Tomato has ranks second next to potato in world acreage, but it has rank first among processing crops. In the present study, tomato plants treated with Rhizophora apiculata as seed treatment at 15% and as foliar spray at 30 and 45 days after treatment (DAT), co-inoculated with the Alternaria solani pathogen, recorded maximum activity of the defense related enzymes and PR proteins including; peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), catalse, chitinase and β- 1,3 glucanses. Induction of these defense enzymes was studied in vivo in treated tomato plants grown in the greenhouse. Moreover, the healthy control tomato plants also showed slight increase in activities of all these defense enzymes up to four days, and thereafter showed gradual decline. The aim of the present investigation was to access the induction of the defense enzymes and PRproteins in tomato plants infested with A. solani, through the application of R. apiculata extract. Accordingly, we can reduce the incidence of early blight disease in these tomato plants. Current findings recorded the earlier and higher accumulation of the defense enzymes and PR-proteins mainly; PO, PPO, PAL, β- 1, 3 glucanse and chitinase in tomato plants, resulting in significant reduction in early blight infection.

Mangrove forest in Lubuk Kertang Village, West Brandan sub-district has been converted around 20 ha annually (1996–2016) into various non-forest land use. Rehabilitation can be a solution to restore the condition of the ecosystem so that it can resume its ecological and economic functions. This paper discusses the evaluation of mangrove rehabilitation carried out by planting 6000 propagules in December 2015 and 5000 seedlings in May 2016 with Rhizophora apiculata species in abandoned ponds. Monitoring was carried out every 6 months from 2016 to 2022. In the restored area, 11 true mangrove species and 3 associated mangrove species were found. The percentage of plants that survived after seven years was 69.42% for planting using propagules and 86.38% for planting with seedlings. The total biomass carbon stocks stored by 7-year-old plants using propagules was 51.18 Mg ha−1, while the carbon stored by planting using seedlings was 56.79 Mg ha−1. Soil carbon stocks at the planted site with propagules were 506.89 ± 250.74 MgC ha−1, and at the planted site with seedlings were 461.85 ± 102.23 MgC ha−1. The total ecosystem carbon stocks (including aboveground carbon) in the planted site using propagules were 558.07 MgC ha−1, while planting using seedlings were 518.64 MgC ha−1. The dataset and findings on the carbon storage evaluation of mangrove rehabilitation will be useful for blue carbon research community and policymakers in the context of the climate change mitigation strategy for Indonesia.

In this study, 16S high-throughput and metagenomic sequencing analyses were employed to explore the changes in microbial community and function with the succession of mangroves (Sonneratia alba, Rhizophora apiculata, and Bruguiera parviflora) along the Merbok river estuary in Malaysia. The sediments of the three mangroves harbored their own unique dominant microbial taxa, whereas R. apiculata exhibited the highest microbial diversity. In general, Gammaproteobacteria, Actinobacteria, Alphaproteobacteria, Deltaproteobacteria, and Anaerolineae were the dominant microbial classes, but their abundances varied significantly among the three mangroves. Principal coordinates and redundancy analyses revealed that the specificity of the microbial community was highly correlated with mangrove populations and environmental factors. The results further showed that R. apiculata exhibited the highest carbon-related metabolism, coinciding with the highest organic carbon and microbial diversity. In addition, specific microbial taxa, such as Desulfobacterales and Rhizobiales, contributed the highest functional activities related to carbon metabolism, prokaryote carbon fixation, and methane metabolism. The present results provide a comprehensive understanding of the adaptations and functions of microbes in relation to environmental transition and mangrove succession in intertidal regions. High microbial diversity and carbon metabolism in R. apiculata might in turn facilitate and maintain the formation of climax mangroves in the middle region of the Merbok river estuary.

Mangrove productivity depends on the storage of nutrients and elements. Elemental concentrations were examined in leaves, roots, and sediments for three age stands (15, 25 years, and VJR) of Rhizophora apiculata in the Matang Mangrove Forest Reserve (MMFR). Six compartments with two compartments each for each age group were used to analyze sixteen elements. Four types of elemental patterns were examined with decreasing order during analysis: (1) Cd < Cu < Pb < Zn < Mg < Mn < Fe < K < Na < Ca and P% < S% < N% < C% in leaves, (2) Cd < Pb < Cu < Zn < Mg < Mn < Fe < K < Na < Ca and P% < S% < N% < C% in roots, (3) Cd < Pb < Cu < Zn < Mg < Mn < K < Fe < Na < Ca and P% < N% < S% < C% in sediment samples and (4) Cd(S) < Pb(S) < Cu(S) < Zn(S) < Mg(S) < Mn(L) < K(L) < Fe(S) < Na(R) < Ca(R) and P%(S) < S%(S) < N%(L) < C%(R) collectively for all samples. Evidence that elements do not store primarily in above-ground biomass can be found in the observation that elements are stored more in sediment and roots. The outcome of the present study shows that the rate of increase of elements in trees (leaves and roots) was less as compared to sediments, where the elemental concentration increased considerably with time. Elemental concentration comparison within three age classes showed that C, N, and S were significantly different in all three types of samples. The δ15N ratios showed positive values in all six compartments which supported the concept that the δ15N ratio could not be observed in N concentration in this study. The δ13C values showed more negative values in all six compartments which represented less salinity and a freshwater intake. The S, P, and heavy metals concentrations were high. The concentrations of Cd, P, N, C, and S in the sediment influenced variations in four compartments in accordance with the three mangrove age groups. The results of this study can be utilized to create management plans for MMFR and conduct risk assessments of the elements’ concentration in sediment.

Rhizophora apiculata is one of the most widespread and economically important mangrove trees in the Indo-West Pacific region. Knowledge of the genetic variation of R. apiculata in Thailand is limited. Here, we generated a whole-genome sequence of R. apiculata using the 10× Genomics technology. R. apiculata genome assembly was 230.47 Mb. Based on its genome, 2640 loci of high-quality biallelic SNPs were identified from 82 R. apiculata accessions collected from 17 natural mangrove forests in Thailand to assess the genetic diversity and population structure among them. A moderate level of genetic diversity of R. apiculata was observed. The average observed heterozygosity (Ho = 0.48) was higher than the average expected heterozygosity (He = 0.36). Two subpopulations were observed and confirmed from three approaches: population structure, PCA, and phylogenetic analyses. They corresponded to the Gulf of Thailand and the Andaman Sea separated by the Malay Peninsula. AMOVA analyses indicated that genetic variation was attributable to 76.22% within populations and 23.78% among populations. A high level of genetic differentiation between the two subpopulations (FST = 0.24, p < 0.001) was observed. This study evaluated the genetic diversity and population structure of R. apiculata, providing useful information for sustainable mangrove management in Thailand.

Induction of defence enzymes and PR-protein in rice plants treated with Pseudomonas fluorescens and Rhizophora apiculata individually or in combinations against bacterial leaf blight (BLB) disease in rice was studied. Challenged inoculation of Xanthomonas oryzae pv. oryzae under pot culture conditions was used. The plants treated with P. fluorescens at the rate of 10 mL/kg and R. apiculata at 15% gave maximum defence through enzymes and PR-proteins viz., peroxidase (PO, 2.98), polyphenoloxidase (PPO, 2.06), phenylalanine ammonia-lyase (PAL, 19.55), catalase (2.01), chitinase (5.12), β-1,3-glucanase (54.56), and phenols (21.84). Seed treatment with P. fluorescens at 10 mL/kg concentration and foliar spray with P. fluorescens at 0.5% were statistically significant and similar in inducing the PO (2.83), PPO (1.73), and PAL (19.01) activities. Enhancement of defence enzymes and PR-Proteins in rice crops treated with R. apiculata and P. fluorescens plays a significant role in managing rice BLB disease. [ABSTRACT FROM AUTHOR]

Hongru Zhang,1 Joe Antony Jacob,2 Ziyu Jiang,3 Senlei Xu,1 Ke Sun,1 Zehao Zhong,1 Nithya Varadharaju,4 Achiraman Shanmugam21The Second Clinical Medical College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China; 2Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli, 620024, Tamil Nadu, India; 3Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing 210028, Jiangsu, People’s Republic of China; 4Department of Animal Health and Management, Alagappa University, Karaikudi 630 003, Tamil Nadu, IndiaBackground: Liver plays a vital role in the elimination of xenobiotics that can induce hepatotoxicity in living organisms.Silver nanoparticles have evolved recently as an alternative in various industries and are used for their biomedical applications.Rhizophora apiculata is a least studied mangrove-based plant that has been used in the traditional medicine of Southeast Asia for its healing properties. It is a well-known fact that the generation of free radicals has been associated with oxidative stress. Methods: Hence, in this study we used carbon tetrachloride as a hepatotoxin to induce liver damage. The protective effects of silver nanoparticles synthesized using Rhizophora apiculata on hepatotoxin-induced liver damage in experimental mice were assessed. Results: The results of the assessment indicate that silver nanoparticles were effective in protecting the liver from damages induced by carbon tetrachloride. Conclusion: Among existing literature, this is the first ever approach for hepatoprotective effect of nanoparticles derived using plant extract from mangrove ecosystem.Keywords: mangroves, Rhizophora apiculata, silver nanoparticles, carbon tetrachloride, hepatotoxicity

The carbon cycle includes important fluxes of methane (CH4) and carbon dioxide (CO2) between the ecosystem and the atmosphere. The fluxes may acquire either positive (release) or negative values (consumption). We calculated these fluxes based on short-campaign in situ chamber measurements from four ecosystems of South Vietnam: intact mountain rain forest, rice field, Melaleuca forest and mangroves (different sites with Avicennia or Rhizophora and a typhoon-disturbed gap). Soil measurements were supplemented by chamber measurements of gas fluxes from the tree stems. Measuring CH4 and CO2 together facilitates the assessment of the ratio between these two gases in connection with current conditions and specificity of individual ecosystems. The highest fluxes of CH4 were recorded in the Melaleuca forest, being within the range from 356.7 to 784.2 mg CH4–C m−2 day−1 accompanied by higher fluxes of CH4 release from Melaleuca tree stems (8.0–262.1 mg CH4–C m−2 day−1). Significant negative soil fluxes of CH4 were recorded in the mountain rain forest, within the range from − 0.3 to − 0.8 mg CH4–C m−2 day−1. Fluxes of CO2 indicate prevailing aerobic activity in the soils of the ecosystems investigated. Quite a large variability of CO2 fluxes was recorded in the soil of the Avicennia mangroves. The in situ measurements of different ecosystems are fundamental for follow-up measurements at different levels such as aerial and satellite gas fluxes observations. [ABSTRACT FROM AUTHOR]

Mangrove forests are distributed in the intertidal zones of tropical and subtropical regions, and have been severely damaged by anthropogenic activities, climate change, and stochastic events. Although much progress has been made in the conservation and restoration of mangroves in China, studies of the genetic diversity of mangroves are lacking, especially for isolated populations, yet such studies are essential for guiding conservation and restoration efforts. Here, we evaluated the genetic diversity, spatial genetic structure, and mating system of two mangrove species, Rhizophora apiculata and Avicennia marina, in a heavily disturbed area in Tielu Harbor, Sanya City, Hainan Island, China, using 18 nuclear microsatellite markers. We found that the genetic diversity of R. apiculata, which is classified as ‘Vulnerable’ in the China Red List categories, was high and similar compared with the genetic diversity estimates of other populations reported in previous studies. In contrast, the genetic diversity of A. marina, which is classified as a species of ‘Least Concern’, was low compared with the genetic diversity estimates of other populations. We then evaluated the presence of genetic bottlenecks, spatial genetic structure, and the mating system to determine the effects that habitat destruction has had on these two species. Our findings indicate that distinct conservation and restoration approaches are needed for these two species. Generally, our results provide valuable information that will aid the development of conservation and restoration strategies for the mangroves of Tielu Harbor.

Mangrove health is very important for the ecosystem to survive the challenges and threats due to climate change and anthropogenic pressures. However, unhealthy mangroves due to pathogenic fungi causing diseases may demote the survival rate of younger plants to grow and information on the status of foliar disease incidence is limited. This study aimed 1) to observe the foliar disease symptoms that occurred on Rhizophora apiculata and Avicennia marina and 2) to identify the fungi isolated from the symptomatic leaves. Samples were collected from the mangrove area located in Universiti Malaysia Terengganu (UMT) campus, along the South China Sea. All isolates were identified based on their morphological characteristics. A total of five foliar disease symptoms were observed namely black leaf spot, grey leaf spot, leaf rot, sunken leaf blight, and anthracnose. Rhizophora apiculata has a greater number of leaf spots than A. marina. Four genera of fungi; Pestalotiopsis sp., Curvularia sp., Colletotrichum sp. and Rhizopus sp. were successfully isolated from symptomatic leaves where the most dominant was Pestalotiopsis sp. to both mangrove species. This finding highlights the need to obtain the status of foliar diseases and their impact on the resilience of mangroves in Malaysia. [ABSTRACT FROM AUTHOR]

Seed dispersal study is essential to understand the population dynamics, which is fundamentally important to support the conservation and management of mangrove ecosystem. A laboratory study was conducted to investigate the propagule dispersal properties of two important mangrove species in Malaysia, Avicennia marina and Rhizophora apiculata. Propagules of both species were collected from the wild and released into the salinity treatments of 0, 10, 20 and 30 ppt. The dispersal properties of the propagules were observed for 60 days. In the saltwater, A. marina propagules showed high viability rate, always buoyant and developed roots and shoots rapidly while R. apiculata propagules also presented high viability rate, but their buoyancy depended on salinity and they had slower growth rate. Both species developed poorly in the freshwater especially those of A. marina. Overall, the propagule dispersal properties were significantly different between species and between freshwater and saltwater. A. marina propagules possess greater attributes to be dispersed in open coast while R. apiculata propagules are more adapted to the inland areas. The dispersal potentials of both species were found corresponded to their natural distributions in the west coast of Peninsular Malaysia. This supports the notion that propagule dispersal is one of the determinants of species distribution and abundance. [ABSTRACT FROM AUTHOR]

Until recently, peatlands in Cambodia were relatively unknown despite numerous efforts to locate and identify them. In 2012–2014, mangrove vegetation on the south-western coast of Cambodia was found to be growing on top of a peat layer underlain by marine clay. Believing that more mangrove peat might remain to be discovered, additional surveys were conducted in 2015, focusing on part of the east coast of Botum Sakor National Park and the riverine mangroves outside the National Park boundary. A total area of 4,768 ha of mangrove peat was confirmed to be present. Overall, the peat layer within this mangrove area is not very thick, with about half of all measurements in the range 50–100 cm and the deepest record 135 cm. In total, 26 mangrove species were recorded during the survey, including 20 tree species. Most were typical (either true or associate) species and very similar to those found in other mangrove forests in Cambodia and elsewhere in Southeast Asia. Although the mangrove peat area confirmed is small, it nevertheless contributes to the total peatland extent and carbon stock of the ASEAN region. Mangrove peat ecosystems, such as the one studied here, are not common in Southeast Asia and deserve more detailed and in-depth studies.

Mangrove plant endophytic bacteria are prolific sources of bioactive secondary metabolites. In the present study, twenty-three endophytic bacteria were isolated from the fresh roots of the mangrove plant Rhizophora apiculata. The identification of isolates by 16S rRNA gene sequences revealed that the isolated endophytic bacteria belonged to nine genera, including Streptomyces, Bacillus, Pseudovibrio, Microbacterium, Brevibacterium, Microbulbifer, Micrococcus, Rossellomorea, and Paracoccus. The ethyl acetate extracts of the endophytic bacteria’s pharmacological properties were evaluated in vitro, including antimicrobial, antioxidant, α-amylase and α-glucosidase inhibitory, xanthine oxidase inhibitory, and cytotoxic activities. Gas chromatography–mass spectrometry (GC-MS) analyses of three high bioactive strains Bacillus sp. RAR_GA_16, Rossellomorea vietnamensis RAR_WA_32, and Bacillus sp. RAR_M1_44 identified major volatile organic compounds (VOCs) in their ethyl acetate extracts. Genome analyses identified biosynthesis gene clusters (BGCs) of secondary metabolites of the bacterial endophytes. The obtained results reveal that the endophytic bacteria from R. apiculata may be a potential source of pharmacological secondary metabolites, and further investigations of the high bioactive strains—such as fermentation and isolation of pure bioactive compounds, and heterologous expression of novel BGCs in appropriate expression hosts—may allow exploring and exploiting the promising bioactive compounds for future drug development.

The efficacy of R. apiculata tested @15% concentration against early blight disease in pot and field trials. The study revealed that seed treatment as well as foliar spray with R. apiculata @ 15% at 30 and 45 DAT (T7) recorded minimum percent disease incidence (15.24%), maximum plant height (79.87cm) and fruit yield (311.54g/plant) over control in pot trial. Also, the same treatment recorded minimum PDI (12.71%) maximum number of fruits per plant (45.67), maximum individual fruit weight (82.63g) and maximum fruit yield (69.33 t/ha) over control in field trial. It was followed by the treatment T6 and T5 in respect of reducing the disease incidence and enhanced the biometric of tomato. [ABSTRACT FROM AUTHOR]

The present investigation was undertaken to assess the antifungal activity of different solvent extract of Rhizophora apiculata against A. solani and evaluation of its antimicrobial compounds. The experiment clearly revealed that all the solvent extracts of R. apiculata (15%) considerably inhibited the growth of test pathogenwhen compared to control. The minimum mycelial growth (3.65mm) was recorded with methanol extract which accounted for the highest percent inhibition (95.54%) over control. This was followed by aqueous extract, ethanol extract and chloroform extract of R. apiculata (15%) accounting 94.47, 92.28 and 89.94 percent inhibition. The standard chemical fungicide Mancozeb 75% WP at 0.25% conc. showed 100 percent inhibition of the test pathogen. Also, 13-Docosenamide, (Z)-, -13-Docosenamide, 9-Octadecenamide, (Z)-was recorded highest peak area with 36.86% with retention time (RT) 25.14 min. ç-Sitosterol, á-Sitosterol, Cholest-8(14)-en-3-ol, 4,4-dimethyl-, (3á,5à) was identified as most abundant compounds of R. annamalayna with 3.31 % peak area with highest retention time (RT) 33.33 min under GC-MS analysis. [ABSTRACT FROM AUTHOR]

A study in enhancing the strength properties of Rhizophora apiculata by turning the solid wood into an engineered laminated board was executed. The matured Rhizophora species was selected from peat swamp forest in Sibu, Sarawak. The trunk was segregated into three parts, namely the bottom, middle and top portion and subsequently sawn into wooden planks. The laminated boards were cut into specific thicknesses and immediately bonded with an adhesive by pressed drying. Preparation for solid and laminated boards testing samples followed the ISO and ASTM standards. Properties such as the moisture content, density, basic density, static bending (MOR and MOE) and compression were determined. The results show an improvement in properties from the solid to laminated board. The values in density, MOR, and MOE increased in the range of 2-6%, 29-42%, and 13-36%, respectively. However, the values of the moisture content, basic density, and compression, indicated a vice versa trend ranging from 1-2%, 2-6%, and 8-24%, respectively. The bottom portion was more durable and robust compared to the other portions. [ABSTRACT FROM AUTHOR]

Disposal of industrial wastewater has resulted in increased concentration of heavy metals (HMs) along the coastline of Malaysia. However, little is known about the accumulation capacity of HMs by Rhizophora apiculata in Matang Mangrove Forest Reserve (MMFR) Malaysia. The aim of this study is to measure the concentration of HMs in different ages of mangrove forests. In this study, 15 and 80-year old trees of Rhizophora apiculata were selected for experimentation. Thirty samples of leaves, roots and sediments were analyzed to measure the concentration of HMs in 15 and 80-year-old trees. The measured concentrations of copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) in leaves, roots and sediments were used to compare bio- concentration and translocation factor between the abovementioned two age groups. Concentration of Mn came out to be significantly higher in leaves than in sediment. This suggested that Rhizophora apiculata was an efficient Mn-extractor. On the other hand, it was found less efficient in extracting heavier metals (Fe, Cu and Zn) from the sediment, as their concentration was lower in leaves and roots as compared to sediments. The translocation factor was highest for Mn, indicating high mobility of Mn from roots towards the leaves. Bio-concentration factor was also found highest for Mn (3.52) followed by Zn (1.88), Cu (1.33) and Fe (0.26). Therefore, it can be concluded that Rhizophora apiculata is more efficient in extracting Mn as compared to Zn, Cu and Fe. [ABSTRACT FROM AUTHOR]

Bioturbation is an important process in the soft-bottom ecosystem to return nutrients in the environment. This study aimed to evaluate the effects of bioturbation activities on the growth of mangrove saplings (Rhizophora apiculata). A caging experiment using a total of 16 plots each measuring 1 × 1 m containing two mangrove saplings in each plot (N=32 saplings) with eight caged and eight uncaged plots were placed randomly in Guang-guang, Davao Oriental, Philippines. The set-up was monitored for five months. The length of internode, number of nodes, leaves and length of branches of the saplings were measured and counted. In addition, the number of mounds, holes and fiddler crabs were also counted in the uncaged, marked plots to determine their activities. Result of the comparison of the number of holes, mounds, and fiddler crabs showed high significant differences with the number of holes in the sediment being greater in the uncaged set-ups (holes > mounds = fiddler crab; P<0.001). Further, the result based on t-test showed high significant differences in terms of internode length (uncaged=35.68 cm vs caged=33.19 cm; t-value=-5.15; P<0.001), number of nodes (uncaged=8.70 vs caged=6.75; t-value=-8.55; P<0.001), and branch length (uncaged=6.0 cm vs caged=5.24 cm; tvalue= -2.73, P=0.008) as well as for the number of leaves (uncaged=7.12 vs caged=6.0 leaves; t-value=-4.83, P<0.001). The study concludes that bioturbation by fiddler crabs can affect the growth of saplings. [ABSTRACT FROM AUTHOR]

The efficacy of R. apiculata tested @15% concentration against early blight disease in pot and field trials. The study revealed that seed treatment as well as foliar spray with R. apiculata @ 15% at 30 and 45 DAT (T7) recorded minimum percent disease incidence (15.24%), maximum plant height (79.87cm) and fruit yield (311.54g/plant) over control in pot trial. Also, the same treatment recorded minimum PDI (12.71%) maximum number of fruits per plant (45.67), maximum individual fruit weight (82.63g) and maximum fruit yield (69.33 t/ha) over control in field trial. It was followed by the treatment T6 and T5 in respect of reducing the disease incidence and enhanced the biometric of tomato. [ABSTRACT FROM AUTHOR]

The present investigation was undertaken to assess the antifungal activity of different solvent extract of Rhizophora apiculata against A. solani and evaluation of its antimicrobial compounds. The experiment clearly revealed that all the solvent extracts of R. apiculata (15%) considerably inhibited the growth of test pathogenwhen compared to control. The minimum mycelial growth (3.65mm) was recorded with methanol extract which accounted for the highest percent inhibition (95.54%) over control. This was followed by aqueous extract, ethanol extract and chloroform extract of R. apiculata (15%) accounting 94.47, 92.28 and 89.94 percent inhibition. The standard chemical fungicide Mancozeb 75% WP at 0.25% conc. showed 100 percent inhibition of the test pathogen. Also, 13-Docosenamide, (Z)-, -13-Docosenamide, 9-Octadecenamide, (Z)-was recorded highest peak area with 36.86% with retention time (RT) 25.14 min. ç-Sitosterol, á-Sitosterol, Cholest-8(14)-en-3-ol, 4,4-dimethyl-, (3á,5à) was identified as most abundant compounds of R. annamalayna with 3.31 % peak area with highest retention time (RT) 33.33 min under GC-MS analysis. [ABSTRACT FROM AUTHOR]

Rhizophora apiculata is a halophytic, small mangrove tree distributed along the coastal regions of the tropical and subtropical areas of the world. They are natural genetic reservoirs of salt adaptation genes and offer a unique system to explore adaptive mechanisms under salinity stress. However, there are no reliable studies available on selection and validation of reference genes for quantitative real-time polymerase chain reaction (qRT-PCR) in R. apiculata physiological tissues and in salt stress conditions. The selection of appropriate candidate reference gene for normalization of qRT-PCR data is a crucial step towards relative analysis of gene expression. In the current study, seven genes such as elongation factor 1α (EF1α), Ubiquitin (UBQ), β-tubulin (β-TUB), Actin (ACT), Ribulose1,5-bisphosphate carboxylase/oxygenase (rbcL), Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and 18S rRNA (18S) were selected and analyzed for their expression stability. Physiological tissues such as leaf, root, stem, and flower along with salt stress leaf samples were used for selection of candidate reference genes. The high-quality expression data was obtained from biological replicates and further analyzed using five different programs such as geNorm, NormFinder, BestKeeper, Delta Ct and RefFinder. All algorithms comprehensively ranked EF1α followed by ACT as the most stable candidate reference genes in R. apiculata physiological tissues. Moreover, β-TUB and 18S were ranked as moderately stable candidate reference genes, while GAPDH and rbcL were least stable reference genes. Under salt stress, EF1α was comprehensively recommended top-ranked candidate reference gene followed by ACT and 18S. In order to validate the identified most stable candidate reference genes, EF1α, ACT, 18S and UBQ were used for relative gene expression level of sodium/proton antiporter (NHX) gene under salt stress. The expression level of NHX varied according to the internal control which showed the importance of selection of appropriate reference gene. Taken together, this is the first ever systematic attempt of selection and validation of reference gene for qRT-PCR in R. apiculata physiological tissues and in salt stress. This study would promote gene expression profiling of salt stress tolerance related genes in R. apiculata.

Mangroves are abundant in bioactive natural substances that fight off pathogenic diseases. Different parts of R. apiculata, an abundant mangrove found in Bhitarkanika National Park, India were extracted with methanol and a mixture of solvents methanol/ethanol/chloroform (60 : 20 : 20) to evaluate their antimicrobial properties. The combination solvent extract of bark had the highest zone of inhibition (ZOI) of 18.62 mm against Pseudomonas aeruginosa and a ZOI of 17.41 mm against Streptococcus mitis. Bark extracts had the highest DPPH (43 %) and FRAP (96 %) activities. The combination solvent bark extract of R. apiculata had the highest ZOI of 20.42 mm (lowest MIC of 2.12 μg/ml) against Candida albicans and ZOI of 15.33 mm (MIC of 3.02 μg/mL) against Penicillium chrysogenum. Combination bark extracts of R. apiculata contained flavanols than methanolic extracts. The crude extract of R. apiculata bark made with a mixture of solvents containing more active ingredients could be used in novel drug formulation., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

Introduction: Rhizophora apiculata is an important traditional medicinal plant used in many people in Asia and Africa for curing of both infectious and non-infectious diseases. Objective: The present study was aimed to evaluate the cytotoxic effect and observation of cell morphology changes of breast cancer (Michigan Cancer Foundation-7 [MCF-7]) cell lines of after the treatment with the methanolic leaf extract of R. apiculata. Materials and Methods: Cytotoxicity of the methanolic leaf extract of R. apiculata was tested against MCF-7 cell lines by using MTT assay and to find the cell morphology of MCF- 7 cells upon exposure to the methanolic leaf extract of R. apiculata by using phase contrast microscope Results: The results showed that the methanolic leaf extract of R. apiculata with different concentrations (25,50, 100, and 200 µg/mL) had shown significant concentration-dependent anticancer (cytotoxic) activity against MCF-7 breast cancer cell by showing 48.27% of cell viability with half maximal inhibitory concentration (IC50) values are of 140.97 µg/ml, comparing with standard tamoxifen by showing 80.80% of cell viability with IC50 values of 61.88 µg/ml. Conclusion: From this study, it can be concluded that the methanolic leave extract of R. apiculata could be serve as a potential source of plant-derived, anticancer agents for the development of therapeutic anticancer drugs and further study has been focused on the isolation of bioactive anticancer compounds present in the methanolic leaf extract of R. apiculata by bioactivity-guided fractionation. [ABSTRACT FROM AUTHOR]

Until recently, peatlands in Cambodia were relatively unknown despite numerous efforts to locate and identify them. In 2012-2014, mangrove vegetation on the south-western coast of Cambodia was found to be growing on top of a peat layer underlain by marine clay. Believing that more mangrove peat might remain to be discovered, additional surveys were conducted in 2015, focusing on part of the east coast of Botum Sakor National Park and the riverine mangroves outside the National Park boundary. A total area of 4,768 ha of mangrove peat was confirmed to be present. Overall, the peat layer within this mangrove area is not very thick, with about half of all measurements in the range 50-100 cm and the deepest record 135 cm. In total, 26 mangrove species were recorded during the survey, including 20 tree species. Most were typical (either true or associate) species and very similar to those found in other mangrove forests in Cambodia and elsewhere in Southeast Asia. Although the mangrove peat area confirmed is small, it nevertheless contributes to the total peatland extent and carbon stock of the ASEAN region. Mangrove peat ecosystems, such as the one studied here, are not common in Southeast Asia and deserve more detailed and in-depth studies. [ABSTRACT FROM AUTHOR]

Rhizophora apiculata is a halophytic, small mangrove tree distributed along the coastal regions of the tropical and subtropical areas of the world. They are natural genetic reservoirs of salt adaptation genes and offer a unique system to explore adaptive mechanisms under salinity stress. However, there are no reliable studies available on selection and validation of reference genes for quantitative real-time polymerase chain reaction (qRT-PCR) in R. apiculata physiological tissues and in salt stress conditions. The selection of appropriate candidate reference gene for normalization of qRT-PCR data is a crucial step towards relative analysis of gene expression. In the current study, seven genes such as elongation factor 1α (EF1α), Ubiquitin (UBQ), β-tubulin (β-TUB), Actin (ACT), Ribulose1,5-bisphosphate carboxylase/oxygenase (rbcL), Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and 18S rRNA (18S) were selected and analyzed for their expression stability. Physiological tissues such as leaf, root, stem, and flower along with salt stress leaf samples were used for selection of candidate reference genes. The high-quality expression data was obtained from biological replicates and further analyzed using five different programs such as geNorm, NormFinder, BestKeeper, Delta Ct and RefFinder. All algorithms comprehensively ranked EF1α followed by ACT as the most stable candidate reference genes in R. apiculata physiological tissues. Moreover, β- TUBand 18S were ranked as moderately stable candidate reference genes, whileGAPDH and rbcL were least stable reference genes. Under salt stress, EF1α was comprehensively recommended top-ranked candidate reference gene followed by ACT and 18S. In order to validate the identified most stable candidate reference genes, EF1α, ACT, 18S and UBQ were used for relative gene expression level of sodium/proton antiporter (NHX) gene under salt stress. The expression level of NHX varied according to the internal control which showed the importance of selection of appropriate reference gene. Taken together, this is the first ever systematic attempt of selection and validation of reference gene for qRT-PCR in R. apiculata physiological tissues and in salt stress. This study would promote gene expression profiling of salt stress tolerance related genes in R. apiculata. [ABSTRACT FROM AUTHOR]

The inhibitive characteristics of aqueous extracts from mangrove ( Rhizophora apiculata) bark and leaf on the corrosion of mild steel (MS) coupon in 1 M HCl were examined by means of the gravimetric measurement (weight loss), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The MS surface morphologie were investigated using field emission scanning electron microscopy (FESEM) with Energy Dispersive X-Ray Analysis (EDX) at 120h in the presence and absence of green inhibitors in corrosive medium. Respective inhibition efficiencies of 68.1% and 59.0% were obtained when exposed to 10% v/v Rhizophora apiculata solution for 72h. Examination of the adsorption behavior of the solutions indicated the Langmuir isotherm model as being the most likely relevant adsorption mechanism. In addition, polarization measurements showed that both bark and leaves extract inhibitors act via mixed type inhibition. [ABSTRACT FROM AUTHOR]

Many mangrove forests have suffered from the contaminated environments near industrial areas. This study addresses the question how these environments influence the renewal of mangrove forests. To this end ecophysiological responses of the young mangrove species Rhizophora apiculata (Blume) grown under combinations of the factors heavy metals (here chromium), nutrition and soil/water environment were analyzed. We tested the hypothesis that soil/water conditions and nutrient status of the soil strongly influence the toxic effect of chromium. Seedlings of R. apiculata were grown in three different soil/water environments (natural saline soil with brackish water, salt-leached soil with fresh water and salt-leached-sterilized soil with fresh water) treated with different levels of chromium and NPK fertilizer. The system was inundated twice a day as similar to natural tidal condition in the mangrove wetland in the south of Vietnam. The experiments were carried out for 6 months. Growth data of root, leaf and stem, root cell number and stomata number were recorded and analyzed. Results showed that growth of R. apiculata is slower in natural saline soil/water condition. The effect of chromium and of nutrients respectively depends on the soil/water condition. Under high concentrations of chromium, NPK fertilizer amplifies the toxic effect of chromium. Stomata density increases under chromium stress and is largest under the combination of chromium and salty soil/water condition. From the data a nonlinear multivariate regression model was derived capturing the toxicity threshold of R. apiculata under different treatment combinations. [ABSTRACT FROM AUTHOR]