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Elevated human-induced activities have prompted significant uncontrolled release of potentially toxic metals (PTM) to the undisturbed ecosystem throughout the globe. Riparian mangrove vegetations act as a natural purifier of wastewaters and assist in maintaining a healthy ecosystem. We have investigated the elevated PTM-induced stress and biotic response of two riparian mangrove species e.g. Sonneratia caseolaris and Avicennia officinalis by river Hooghly. The increased PTM concentrations were observed throughout the river bank; with the maximum pollution load at Chemaguri (S9). Except Co, Cr and Pb, higher enrichment factor (1.97–8.89) and contamination factor (0.64–2.88) values were observed for Cd, Cu, Fe, Zn. Mn, and Ni. Geo-accumulation index (−2.2 – 0.92) values indicates natural geogenic accumulation of Cu in the riparian mangrove sediment. Thus, sediment quality indices suggest except Cu, enrichment of all studied PTMs was sourced from anthropogenic activities. The sediment of the region when compared with consensus-based sediment quality guidelines shows considerable ecotoxicological risks and threat towards human health considering Ni accumulation. The highest potential ecological risk index value was observed in Chemaguri (S9). The biotic response of riparian mangroves was characterized by reduced photosyhthetic pigments (Chlorophyll a and Chlorophyll b) and increased activity of antioxidative stress enzymes (POD, CAT and SOD). Significant statistical relationship between antioxidative enzyme activity, photosynthetic pigments and bioaccumulated PTMs reflects active functioning of detoxification mechanism in the riparian mangrove species.

Variations in stem biomass and carbon density in 12 mangrove species were studied to understand the potential of carbon storage in the live biomass of Bhitarkanika mangrove ecosystems, South-East Coast of India. The results highlighted significant inter-species variations (p C org / N tot ratios followed by Heritiera fomes. Further, the higher carbon sequestration capacity of these two mangrove species was confirmed through Principal Component Analysis (PCA). C org , C org / N tot and cellulose/protein ratio were strongly associated with the wood density of the studied mangrove species. Mangrove stem diameter (at breast height; DBH), wood density and tree height were used to estimate the above-ground biomass of all the species, which showed remarkably higher biomass for Avicennia officinalis. Possible adaptation of these species under extreme environmental conditions in addition to variations in vessel wall thickness caused by differential carbon fixation and storage in the form of biomass could explain the variability in elemental properties of mangrove stem wood. Heritiera littoralis and Kandelia candel with relatively higher lignin to cellulose content showed greater potentials to sustain biotic and abiotic stresses and indicated higher carbon sequestration as recalcitrant biomass. The lowest carbon density and highest ratio of cellulose/lignin in the Sonneratia apetala and Sonneratia caseolaris species indicated faster plant growth compared to the other studied species. FTIR analysis evidenced that the increase in the 1728–1733 cm −1 band height assigned to cellulose and decrease in the 1517–1519 cm −1 band height assigned to lignin.

The genetic assembly of Avicennia marina (Forsk.) Vierh, Avicenniaceae within and between the three natural mangrove forests of Kerala coast belonging to the districts of Kochi, Kozhikode and Kannur was investigated using Inter Simple Sequence Repeat (ISSR) markers to provide coherent scientific conservation practices. The ten selective ISSR primer combinations of 60 genotypes of Avicennia marina ensured a total of 171 bands of which 84.5% were polymorphic. Gene diversity index H varied from 0.142 Kochi to 0.195 Kozhikode. The mean gene diversity HS was 0.169 and the total gene diversity HT was 0.262 which showed a moderate level of genetic diversity in the studied population. The mangrove Avicennia marina populations showed large genetic difference GST = 0.3849, indicating that 38% of the total genetic diversity was among the populations and the rest 62% resides within the population. The gene flow estimates Nm = 0.79 shown that natural mangroves of Kerala are in the course of differentiation due to genetic drift. We investigated the genetic distinctiveness of taxonomically confusing species, Avicennia marina and Avicennia officinalis, and resulted in clear demarcation between the two. There is a significant correlation between dendrogram and PCoA designated that extensive distant spreading of seeds between populations of Avicennia marina is comparatively low. The genetic study contributed relatively high diversity and strong differentiation across the three eco-geographic locations. The best remedy to preserve coastal mangrove species like Avicennia marina is to plant the identical species in its respective habitat. Launch, on-site protection zones to safeguard the species and to decrease the impact of human activities would allow its habitats to increase in size through natural regeneration.

The species-specific potentiality of mangroves in terms of ecosystem services is not well understood. Therefore, this study addressed the carbon sequestration and litterfall production potentiality of six major species in Sundarbans, Bangladesh, by evaluating three consecutive years of inventory data, including the stand variables and weather events impacts on them. The total mean aboveground, belowground biomass, biomass accumulation, and carbon accumulation rate were 243.4 Mg ha−1, 132.2 Mg ha−1, and 14.3 Mg ha−1 yr−1, 7.2 Mg ha−1 yr−1, respectively. Carbon stocks and sequestration rates are significantly influenced by stand variables such as diameter, density, and species composition. Large-sized trees and stands with lower density sequester more carbon than small-sized trees, and higher density stands. Among species, Avicennia officinalis contributed higher carbon to carbon stocks and also significantly different from other species for sequestering carbon, whereas Aglaia cucullata was the lowest. Mean annual litterfall was 10.01 Mg ha−1 yr−1, with the maximum litterfall for Hereteira fomes (19.2 Mg ha−1 yr−1) during the late summer or wet season (e.g., April to August). Litterfall showed a significant positive (p

The release of nutrients and anti-nutrients from mangrove leaf litter plays an important role in the biogeochemical cycling in aquatic environments and directly or indirectly affects water quality and food availability to shrimp. In this study, we assessed nutrient and anti-nutrient loss during decomposition of leaf litter at a concentration of 1 g/L for four mangrove species (Avicennia officinalis, Heritiera fomes, Sonneratia apetala, Sonneratia caseolaris) to monitor water quality and to estimate how leaf litter influences shrimp post larvae (PL) growth and survival. There were significant differences (P < 0.05) between the studied species in terms of mass loss of the leaf litter during the investigation period. There were also significant differences (P < 0.05) between the studied species in terms of loss of nutrients and anti-nutrients in the shrimp PL rearing tank during the four-week experimental period. Decomposing mangrove leaves stimulated availability of natural food for shrimp PLs. There was a strong positive correlation between mass loss and PL production. At the concentrations of leaf litter used, the anti-nutritional factors did not affect the PLs. PL survival with mangrove leaf litter was 75–82%, whereas all the PL died without any leaf litter. PL weight gain ranged from 0.83–3.33 mg/d where S. apetala leaf litter resulted in the highest PL growth rate, followed by A. officinalis, S. caseolaris and H. fomes, in that order (P < 0.05). Overall, mangrove leaf litter had a positive effect on shrimp performance in terms of growth and survival and this effect was highest for S. apetala leaf litter.

Adaptive phenotypic plasticity of Avicennia officinalis across the salinity gradient in the Sundarbans of Bangladesh was studied. Propagule morphology was compared through use of a completely randomized design. Propagule growth initiation traits across the salinity gradient (from 0 to 35 ppt at 5 ppt interval) were studied by means of a randomized block design. Propagules showed variability in length, width, and weight across the salinity gradient in the Sundarbans. Propagule growth initiation time, mean growth initiation time, growth initiation index, and propagule growth initiation percentage of A. officinalis varied significantly with the increasing salinity and among low, medium, and high saline zones. However, propagules originating from the high and medium saline zones started their growth initiation more rapidly and vigorously at high salinities compared to those from the low saline zone. Therefore, A. officinalis exhibited adaptive phenotypic plasticity in terms of variability in propagule size and weight as well as physiologically adaptive plastic responses during propagule growth initiation across the salinity gradient in the Sundarbans. A. officinalis in high and medium saline zones of Sundarbans is the most salt-adapted phenotype, and a good knowledge about this will be widely useful for successful regeneration, coastal afforestation, and conservation of this species in increasing saline environments in the future.

The stimulation or suppression of the immune response may modulate disease free state. Herbal medicine paved way for immunmodulation role in many mmunological disorder. The present study was aimed to prove the traditional claim on the theimmunomodulatory activity ofAvicenniaofficinalisagainst autoimmune diseases. TheAvicenniaofficinalis leaves was authentified and coarsely powdered then extracted successively with n-hexane,70% hydroalcohol followed by, ethylacetate. The phytoconstituentsofthe three extracts were analysed . Finally, all were subjected to (NBT) Nitrobluetetrazolium Assay, Candidacidal assay and Phagocytotic evaluation. The percentage yield and phytoconstituents of the extracts were determined. Among thethree extract, the ethanolic extract and Ethylacetateextractshowed effective immunomodulatory effect by their suppression of leucocytes and neutrophils. The results of the present study proved the immunomodulatory effect of Avicenniaofficinalis and further studies are essential to target this species against autoimmune diseases.

Background The article presents the first estimates of biomass and productivity for mangrove forests along the Oligohaline zone of the Sundarbans Reserve Forest (SRF), Bangladesh. This study was conducted overone year from March 2016 to April 2017. Stand structure, above and below-ground biomass changes, and litterfall production were measured within a 2100 m2 sample plot. Methods All trees in the study plots were numbered and height (H) and diameter at breast height (DBH) were measured. Tree height (H) and DBH for each tree were measured in March 2016 and 2017. We apply the above and belowground biomass equation for estimating the biomass of the mangrove tree species (Chave et al. Oecologia 145:87−99, 2005; Komiyama et al. J Trop Ecol 21:471–477, 2005). Litterfall was collected using 1-mm mesh litter traps with collection area of 0.42 m2. Net Primary Production (NPP) was estimated by the summation method of Ogawa Primary productivity of Japanese forests: productivity of terrestrial communities, JIBP synthesis (1977) and Matsuura and Kajimoto Carbon dynamics of terrestrial ecosystem: Systems approach to global environment (2013). Results Heritiera fomes has maintained its dominance of the stand and also suffered the highest tree mortality (2.4%) in the suppressed crown class. The total above-ground biomass (AGB) and below-ground biomass (BGB) of the studied stand was 154.8 and 84.2 Mg∙ha−1, respectively. Among the total biomass of the trees, 64.8% was allocated to AGB and 35.2% to BGB. In case of species-wise contribution of biomass allocation, Avicennia officinalis showed the highest score and Aglaia cucullata the lowest. Mean annual total litterfall was 10.1 Mg∙ha−1∙yr−1, with the maximum litterfall in winter or dry season and late summer or rainy season. The mean AGB increment and above-ground net primary productivity (AGNPP) were 7.1 and 17.2 Mg∙ha−1∙yr−1, respectively. Total net primary productivity (NPP) was estimated to be 21.0 Mg∙ha−1∙yr−1 over the observed period. The results in the Sundarbans mangrove forests exhibited that mangrove communities with similar height and diameter produced different biomass production with the different basal area. The present analysis revealed that the root biomass was large enough and the mean ratio of above−/below-ground biomass was estimated to be 1.84. Conclusions Mangrove communities growing at the oligohaline zone of the Sundarbans, Bangladesh showed high biomass and net primary production indicating their ecological and conservation significance that may be considered in future decision making process for the area as well as in understanding the role of Sundarbans mangrove forest on mitigating the effect of global warming.

Salinity affects growth and development of plants, but mangroves exhibit exceptional salt tolerance. With direct exposure to salinity, mangrove roots possess specific adaptations to tolerate salt stress. Therefore, studying the early effects of salt on mangrove roots can help us better understand the tolerance mechanisms. Using two-month-old greenhouse-grown seedlings of the mangrove tree Avicennia officinalis subjected to NaCl treatment, we profiled gene expression changes in the roots by RNA-sequencing. Of the 6547 genes that were differentially regulated in response to salt treatment, 1404 and 5213 genes were significantly up- and down-regulated, respectively. By comparative genomics, 93 key salt tolerance-related genes were identified of which 47 were up-regulated. Upon placing all the differentially expressed genes (DEG) in known signaling pathways, it was evident that most of the DEGs involved in ethylene and auxin signaling were up-regulated while those involved in ABA signaling were down-regulated. These results imply that ABA-independent signaling pathways also play a major role in salt tolerance of A. officinalis. Further, ethylene response factors (ERFs) were abundantly expressed upon salt treatment and the Arabidopsis mutant aterf115, a homolog of AoERF114 is characterized. Overall, our results would help in understanding the possible molecular mechanism underlying salt tolerance in plants.

Mangrove pneumatophores (respiratory roots) form a unique habitat about which very little ecological information is available. In this study, epiphytic diatoms on the pneumatophore surface of Avicennia officinalis (L.) were investigated with a focus on their seasonal and vertical distribution. The results indicated that among the seasons, highest diatom abundance was observed in monsoon. Vertically, maximum abundance was observed on 0–5 cm of the pneumatophore during post-monsoon and pre-monsoon and then gradually decreased upwards, but during monsoon, 5–10 cm section hosted maximum abundance. There was a seasonal and vertical variation on the diatom abundance and their interactive effect. This is because diatoms probably avoid the basal section (0–5 cm) of the pneumatophore during monsoon due to excessive sediment burial caused by intense riverine flux and settlement of suspended material. Overall it was found that vertically, diatoms (>70%) are mainly concentrated on the lower 0–10 cm of the pneumatophore, probably because this section remains moist during emersion period (low tide). Among the diatoms, Melosira nummuloides and Bacillaria paradoxa exhibited dominance during the monsoon, whereas Thalassiosira spp., Navicula spp., and Nitzschia spp.were prevalent during post- and pre-monsoon. To the best of our knowledge, this is the first study describing the composition of epiphytic diatoms from the pneumatophore surface of A. officinalis. Keeping in mind that these aerial roots together greatly enhance the surface area for attachment of epiphytic diatoms, their cumulative primary production would probably surpass that of mangroves on a quantitative basis and needs future investigation.

Mangrove sediment-associated bacteria are of significantly important in the field of medicine and pharmaceuticals as new promising sources of biologically active pharmacophores due to the extreme conditions, such as high salt concentration and soil anoxia. The sediment bacteria associated with Acanthus ilicifolius and Avicennia officinalis collected from the Mangalavanam mangrove ecosystem of the Kerala State of India were evaluated using various in vitro models for the assessment of their pharmacological properties. The bacteria exhibiting significant antioxidant and antimicrobial activities were isolated, identified, and characterized by the integrated microbiological, biochemical, and 16S rRNA sequencing. Among the varied bacteria isolated from mangrove sediments, Bacillus amyloliquefaciens MBMS5 (GenBank accession number MK765025) exhibited significant antimicrobial activities against various pathogenic bacteria, such as Aeromonas caviae, Vibrio parahemolyticus, and methicillin-resistant Staphylococcus aureus. The extracellular extracts of B. amyloliquefaciens MBMS5 exhibited potential antioxidant activity against free radical species coupled with anti-inflammatory property as displayed by the attenuation activity against pro-inflammatory 5-lipoxygenase.

Expression of AoNHX1 from the mangrove Avicennia increases salt tolerance of rice and Arabidopsis, and specific bHLH transcription factors regulate AtNHX1 and AtNHX6 in Arabidopsis to mediate the salinity response. Improving crop plants to better tolerate soil salinity is a challenging task. Mangrove trees such as Avicennia officinalis have special adaptations to thrive in high salt conditions, which include subcellular compartmentalization of ions facilitated by specialized ion transporters. We identified and characterized two genes encoding Na+/H+ exchangers AoNHX1 and AoNHX6 from Avicennia. AoNHX1 was present in the tonoplast, while, AoNHX6 was localized to the ER and Golgi. Both NHXs were induced by NaCl treatment, with AoNHX1 showing high expression levels in the leaves and AoNHX6 in the seedling roots. Yeast deletion mutants (ena1-5Δ nha1Δ nhx1Δ and ena1-5Δ nha1Δ vnx1Δ) complemented with AoNHX1 and AoNHX6 showed increased tolerance to both NaCl and KCl. Expression of AoNHX1 and AoNHX6 in the corresponding Arabidopsis mutants conferred enhanced NaCl tolerance. The underlying molecular regulatory mechanism was investigated using AtNHX1 and AtNHX6 in Arabidopsis. We identified two basic helix–loop–helix (bHLH) transcription factors AtMYC2 and AtbHLH122 as the ABA-mediated upstream regulators of AtNHX1 and AtNHX6 by chromatin immunoprecipitation. Furthermore, expression of AtNHX1 and AtNHX6 transcripts was reduced in the atmyc2 and atbhlh122 mutants. Lastly, transgenic rice seedlings harboring pUBI::AoNHX1 showed enhanced salt tolerance, suggesting that this gene can be exploited for developing salt-tolerant crops.

Mangrove plants are endowed with various biologically active compounds which have potent antibacterial and antioxidant properties. In present study, a bioactivity-guided fractionation for antibacterial and antioxidant active metabolites from the twigs of Avicennia officinalis collected from Kuala Selangor Nature Park, Selangor, Malaysia gave 13 major fractions. The antibacterial activity of A. officinalis fractions using well-diffusion showed strong selectivity on the Gram-positive bacteria (Staphylococcus epidermidis, S. aureus and Bacillus subtilis) with minimum inhibition concentration (MIC) values of 0.156-5.00 mg/mL. However, no antibacterial activities were observed on the Gram-negative bacteria (Vibrio cholera, Enterobacter cloacae and Escherichia coli). The active antibacterial fractions were further isolated using several chromatographic techniques to give two naphthofuranquinones, namely, avicenol C (1) and stenocarpoquinone B (2). Meanwhile, the antioxidant activity of A. officinalis fractions were evaluated using DPPH radical scavenging assay exhibited low antioxidant activities. Molecular structure of the naphthofuranquinones was elucidated using 1 D and 2 D NMR spectroscopy.

Although studies on species-level classification and mapping using multisource data and machine learning approaches are plenty, the use of data with ideal placement of central wavelength and bandwidth at appropriate spatial resolution, for the classification of mangrove species is underreported. The species composition of a mangrove forest has been estimated utilising the red-edge spectral bands and chlorophyll absorption information from AVIRIS-NG and Sentinel-2 data. In this study, three dominant species, Heritiera fomes, Excoecaria agallocha and Avicennia officinalis, have been classified using the random forest (RF) model for a mangrove forest in Bhitarkanika Wildlife Sanctuary, India. Various combinations of reflectance/backscatter bands and vegetation indices derived from Sentinel-2, AVIRIS-NG, and Sentinel-1 were used for species-level discrimination and mapping. The RF model showed maximum accuracy using Sentinel-2, followed by the AVIRIS-NG, in discriminating three dominant species and two mixed compositions. This study indicates the potential of Sentinel-2 data for discriminating various mangrove species owing to the appropriate placement of central wavelength and bandwidth in Sentinel-2 at ≥10 m spatial resolution. The variable importance plots proved that species-level classification could be attempted using red edge and chlorophyll absorption information. This study has wider applicability in other mangrove forests around the world.

Mangrove forest are used widely for meeting fuelwood needs of local communities in the tropics. However, the implications of fuelwood extraction on mangrove ecology has received very little attention. In this study, we investigated the impact of such small-scale fuelwood harvesting practices on mangrove forest structure, composition, regeneration, and biomass and carbon stocks in a protected area on the east coast of India. We sampled vegetation plots in areas where harvesting was practised and where no harvesting was observed. We found that species composition differed across forest categories with Exoecaria aggalocha and Heriteria fomes dominating non-harvested forest types and Sonneratia apetela, Sonneratia caseolaris, Avicennia officinalis along with mangrove associates comprising a large proportion of harvested mangrove forests. Similarly, tree, sapling and seedling densities, basal area, and biomass and carbon stocks were also found to vary across forest categories, with overall lower values observed in harvested areas. Lastly, total aboveground (11%) and belowground (18%) biomass and carbon stocks were also lower in harvested forests than non-harvested forests. However, large DBH size-class trees were found in harvested areas implying selective cutting practices that conserved old-growth trees and contributed to larger mean carbon pools. As harvesting is selective, mainly for cooking fuel demands, integrated management plans are required to accommodate local cultural and economic needs of the communities in this region.

This study shows results on litterfall dynamics contributing to Net Primary Productivity (NPP) and phenology in three major mixed mangrove habitats in Cochin estuarine system, south-west coast of India. Eleven true mangrove species and three mangrove associates formed the plant biomass where Avicennia officinalis was abundant in Site 1, Excoecaria agallocha in Site 2 and Avicennia officinalis , Rhizophora mucronata were abundant in Site 3. Total tree density varied from 11760 stems ha −1 in Vypin Island (Site 2); 11440 stems ha −1 in Mangalavanam Bird sanctuary (Site 3) and 7680 stems ha −1 , Aroor (Site1). The average stands basal area of the three mangrove habitats were 75.54, 54.85 and 103.26 m 2 ha −1 . The mean annual litterfall production in Cochin mangroves was 16.57±6.58 t ha −1 y −1 in which leaves (53.90%) contributed more followed by flowers, propagules (28.66%) and twigs (17.44%). The spatial variability in litterfall recorded highest in lower latitudinal mangrove habitat, Site.1 followed by Site 2 and Site 3 (2413.36 ± 873.72, 1295.65 ± 401.09, 1263.28±255.28 g DW m −2 y −1 ). Site differences in litter production were statistically significant (one-way ANOVA p 0.001 for total litterfall and p 0.05 for litter components) between the three mangrove habitats. Litter components and total litterfall showed significant seasonality ( p 0.001 ). Highest litterfall was recorded in pre-monsoon period followed by post-monsoon and least in monsoon period. The temporal trend of litterfall was explained through rainfall and mean atmospheric temperature and a negative correlation was there to rainfall during the period. The mean carbon content in the litterfall was estimated as 42.96% of the dry weight and the primary productivity through litterfall in the study area was estimated to be 7.12±2.81 t C ha −1 y −1 . This will act as the major source of carbon input to the mangrove ecosystem and surrounding coastal ecosystems and in turn reflected in NPP.

There are few studies that dealt with species preference in seedling predation by sesarmid crabs in mangrove forests. We investigated predation preference of the sesarmid crab Neosarmatium malabaricum to the seedlings of Aegiceras corniculatum, Avicennia officinalis, Excoecaria agallocha and Rhizophora mucronata in Kunhimangalam mangrove forest in Kerala. Enclosure-exclosure experiments showed that the crab preferred seedlings of E. agallocha the most and that of R. mucronata the least. Reason for this preference was the cumulative effect of morphological and chemical factors of these seedlings. Morphological factors negatively and chemical factors positively influenced the predation preference. Species preference in seedling predation could be inversely proportional to relative abundance and density of saplings. Saplings of the most preferred A. corniculatum and E. agallocha registered low density, and the least preferred R. mucronata and A. officinalis recorded high density in Kunhimangalam mangrove forest. Species preference exhibited by N. malabaricum in seedling predation has been reflected in sapling density and composition. So, this preference can possibly influence the future forest composition.

Absorption, accumulation and translocation of 12 trace elements in nine dominant mangrove plants in the Indian Sundarban Wetland revealed both organ-specific and site-specific characteristics. An overall enrichment of elements was recorded in rhizosediment, exceeding the prescribed effects range-low (ER-L) of consensus based sediment quality guidelines (SQGs) for Cu and Pb. Avicennia officinalis, A. alba, Ceriops decandra and Excoecaria agallocha exhibited unique potential for accumulating Al, Cd, Co, Cr, Cu, Ni, Mn and Zn and could be considered efficient accumulators. Maximum element accumulation in trunk bark (As 6.16, Cr 49.9, Co 2.67, Cu 91.00 and Zn 85.5 mg kg−1) and root/pneumatophore (Al 1000 and Fe 2430 mg kg−1) was recorded. Maximum bioconcentration factor (6.23) in A. officinalis and translocation factor (17.5 for Mn) in C. decandra distinguished their phytoremediation capacity. These halophytes could be used for trace element phytoremediation in stressed sites of Sundarban.

The objective of this present attempt was to investigate the relationship between leaf quality and level of herbivory at study site during August 2010–July 2011. Total amino acids with a maximum of 9.47 mg g −1 during February 2011 in Rhizophora mucronata and a minimum of 4.671 mg g −1 in May 2011 in Avicennia officinalis were noticed. Tannin was maximum (6.844 mg g −1 ) during April 2011 and minimum (0.667 mg g −1 ) in July 2011 in A. officinalis . Total nitrogen showed a maximum of 9.851 mg g −1 during February 2011 in R. mucronata and a minimum of 2.158 mg g −1 in February 2011 in A. officinalis . Total sugars registered a maximum of 4.075 mg g −1 during March 2011 in A. officinalis and a minimum of 0.063 mg g −1 in March 2011 in R. mucronata . Total phosphorus recorded the maximum (4.321 mg g −1 ) during November 2010 in R. mucronata and minimum (0.258 mg g −1 ) during May 2011 in A. officinalis . Potassium content was maximum (3.710 mg g −1 ) during October 2010 in R. mucronata and minimum (0.039 mg g −1 ) in July 2011 in A. officinalis . These data suggest that artificially developed mangrove ecosystems may be an adaptive mechanism related to nutrient conservation, and that it is associated with mangrove survival in phosphorus-deficient soil rather than an adaptation to herbivory.

Aims: Evaluation of cytotoxic potential on the leaves and stem bark extracts of 15 mangrove plants grown in Sri Lanka on breast cancer (MCF -7) and hepatocellular carcinoma (HepG2) cells. Place and Duration of Study: At the Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo between 1 of February 2014 to April 2015. Methodology: Leaves and stem barks of 15 mangrove plants were extracted with hexane, chloroform, ethyl acetate and methanol. Resulting extracts were screened for cytotoxic activity against MCF-7 and HepG2 cells using the Sulforhodamine B (SRB) assay. Original Research Article Samarakoon et al.; EJMP, 14(4): 1-11, 2016; Article no.EJMP.26107 2 Results: Phoenix paludosa, Avicennia officinalis and Scyphiphora hydrophyllacea showed highest cytotoxic properties on cancer cells. Chloroform extract of stem bark of S. hydrophyllacea, Bruguiera gymnorrhiza (chloroform, ethyl acetate and methanol extracts of leaves), hexane and ethyl acetate extracts of leaves of Aegiceras corniculatum, methanol extracts of leaves and stem bark of Nypa fruticans and Rhizophora mucronata, methanol extract of stem bark of Sonneratia alba and Rhizophora apiculata and methanol extract of bark of A. officinalis exerted selective cytotoxicity to HepG2 cells. The hexane extract of leaves of B. gymnorrhiza, chloroform extract of leaves of N. fruticans, ethyl acetate extract of stem bark of Lumnitzera littorea, chloroform extract of leaves of Rhizophora apiculata and chloroform extract of leaves of Pemphis acidula showed selective cytotoxic effects against MCF-7 cells. Out of the 116 mangrove extracts tested, 82 extracts showed no significant cytotoxic effects (IC50>100 μg/mL) against MCF 7 or HepG2 cells. Conclusion: The cytotoxic activities demonstrated by some of the solvent extracts of some mangrove plants provide scientific evidence for their therapeutic potentials and further studies are needed to identify active compounds responsible for cytotoxic effects.

The Sundarbans, the largest mangrove forest in the world and a UNESCO world heritage site has been facing increasing pressure of habitat destruction. Yet, no study has been conducted to test how human disturbances are affecting plant-pollinator interactions in this unique ecosystem. Hence, we aimed to provide the first insight into the impact of habitat loss and human disturbances on the pollinator communities in the Sundarbans. We selected 12 sites in the North-Western region of the Sundarbans, along a gradient of decreasing habitat loss and human activities from forest fragments near human settlements to continuous pristine forest, where we studied insect pollinators of two mangrove plant species, Acanthus ilicifolius and Avicennia officinalis. Our results show that different pollinator groups responded to the disturbance gradient differently. For example, the abundance of Apis dorsata, one of the three local species of honey bees, increased gradually from the village area towards the deep pristine forest. On the other hand, A. cerana and A. florea were found in the village sites and completely absent in the deep forest. Although pollinator community composition changed along the disturbance gradient, their efficacy in pollination did not seem to be significantly affected. However, lower plant diversity and low understory plant cover in the forest patches nearby the village indicated that human disturbances not only affected pollinator community composition but also played a major negative role in the regeneration of the forest. Our study provides first insights into plant-pollinator interactions in the Sundarbans and demonstrates that more research is needed to imply conservation strategies for this unique habitat.

Mangrove endophytic fungi have recently gained attention among researchers as a replacement of mangrove phytoconstituents to protect critically endangered mangrove species. 2,4,6-triphenylaniline (TPA) is an endophytic secondary metabolite isolated from a novel strain Alternaria longipes strain VITN14G derived from mangrove plant Avicennia officinalis to perceive its role in antidiabetic activity. Antidiabetic efficacy of TPA and TPA loaded nanoemulsion formulation (NE) were validated using low dosage (35 mg/kg bw) of streptozotocin (STZ) induced high-fat diet Albino Wistar rats. The diabetic rats were orally administered with TPA (10 mg/kg bw), nano emulsified TPA (10 mg/kg bw) and the standard drug metformin (10 mg/kg bw) respectively once on a daily basis for a period of 48 days. After intervention period, TPA and TPA loaded NE showed controlled blood glucose, significant effect on electrolytes, liver and kidney function test as comparable to standard drug metformin. TPA loaded NE was found to have lesser toxicity on liver, kidney, pancreas and heart than TPA. Moreover, gene expression studies of TPA and TPA loaded NE showed down regulation of PKA and up regulation of AMPK which was similar to the effect of metformin. Therefore, the antidiabetic effect of TPA and TPA loaded NE can be correlated with PKA regulation and vice versa with AMPK regulation. The outcome of this study paves a way to use a natural substitute for existing synthetic antidiabetic drugs.

The forest structure and its relation to environmental parameters of Sundarbans, largest mangrove habitat in India, are presented. Quadrat method was used to analyze the vegetation-environment interaction and structural maturity of mangroves. Floristic studies revealed twenty-seven mangrove species including the critically endangered Sonneratia griffithii and endangered Heritiera fomes. Based on Importance Value Index, Avicennia marina, Excoecaria agallocha, Avicennia officinalis and Avicennia alba were designated as the most important species. Higher diversity indices were observed (Shannon index, ranged from 4.2-1.8; Pielou’s index, 0.96-0.91) revealing greater species diversity and even dispersion of mangroves in Sundarbans. Stem density varied from 133 to 19333 ha−1 and individual basal area 0.4 to 13.4m2ha−1. A very low Maturity Index Value was recorded indicating a low degree of structural maturity. Most of the vegetation parameters (density, species diversity index, β diversity) and few of the edaphic parameters (pH, grain size, total carbon) were found to be in better condition; however, salinity showed significant negative correlations with vegetation characteristics. The study revealed a mixed species composition with intermediate structural development indicating a growing forest in Sundarbans. The data evolved in the study would be fundamental in site-specific management and conservation efforts of mangroves in this world heritage site.

Mangrove forest ecosystems have a very important role for humans and the environment, so to prevent further damage needs to be done identification of tree species composition and structure of mangrove forest stands. For the purpose of this research is to know the composition of tree species from the level of seedling to the tree and to know the structure of its stand. Data collection methods used are Inventory of mangrove species using Indonesian mangrove determination keychain and data analysis by calculating important value index, Diversity index, relative frequency and horizontal structure analysis. The results showed that the largest tree density structure was Rhizophora mucronata of 225 trees / hectare, Avicennia marinna of 145 trees / hectare, Sonneratia alba of 65 trees / hectare and Avicennia officinalis of 65 trees / hectare and had only one crown layer namely strata A which is dominated by Rhizophora mucronata tree which has an average free height of 9 m branch with total height 12 m and diameter 29 cm. For this reason, planting efforts need to be increased to increase the number and composition for coastal protection.

Background Avicennia officinalis is a medicinally important mangrove plant and used in traditional medicinal practices to treat various ailments like rheumatism, paralysis, asthma, dyspepsia, tumors etc. The objective of the present study was to evaluate the carbohydrate metabolizing enzyme inhibitory, antioxidant, antimicrobial and cytotoxic potentials of ethanol leaf and bark extracts of A. officinalis. Methods The carbohydrate metabolizing enzyme inhibition potential was studied by α-amylase and α-glucosidase inhibitory activities. The antioxidant activity was investigated by measuring the scavenging potential of extracts against DPPH, ABTS and superoxide radicals. The antimicrobial activity was studied by agar well diffusion method and the cytotoxicity potential by MTT assay. Results The study revealed that A.offiicnalis bark extract inhibited the activity of α-amylase and α-glucosidase in a dose dependent manner with an IC50 value of 0.66 and 0.71 mg/ml respectively. The leaf extract also demonstrated inhibition potential against α-amylase and α-glucosidase with an IC50 value of 0.29 and 1.19 mg/ml respectively. The ethanol bark extract also exhibited scavenging potential against DPPH, ABTS and superoxide radicals in a dose dependent manner with IC50 values of 112, 114 and 82 μg/ml respectively and ethanol leaf extract with IC50 values of 200, 41.9 and 207.6 μg/ml respectively. Both leaf and bark extracts exhibited dose dependent antiproferative activity on TC1 murine cell lines. Both leaf and bark extracts exhibited antimicrobial activity against bacteria (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and fungi (Candida albicans, C. krusei). The qualitative phytochemical assay, UV-Vis and FTIR analysis revealed the presence of different phytoconstituents in the leaf and bark extracts of A.officinalis. Conclusion The results suggest that ethanol leaf and bark extracts of A.officinalis were effective in inhibiting α-amylase and α-glucosidase and also have antioxidant, antimicrobial potentials which justify the ethnobotanical use of this plant.

The Ganges Delta and Sundarbans comprise the largest continuous mangrove area in the world. These mangroves are subjected to high riverine and tidal dynamics, and the coastline irregularity is characterized by many north-to-south oriented rivers that may hamper dispersal of mangrove propagules. Whereas connectivity levels and resulting population genetic structure often can be explained by ocean currents, other factors may control estuarine-scale mangrove genetic patterns and limit gene flow even between sites in close geographic proximity. We investigated whether the complex estuarine coastline in the Ganges Delta and Sundarbans shaped the genetic structure of Avicennia officinalis populations across regions and rivers at various distances (ca. 1 to 265 km). Using nine microsatellite loci, 433 individuals from 14 populations revealed predominant outcrossing and a high level of genetic variation when compared to other Avicennia species. A moderate but significant level of differentiation was detected among populations (F ST = 0.09), and a principal coordinate analysis clearly separated populations of the Chittagong coastline from the Sundarbans. An individual-based Bayesian analysis also indicated those two gene pools. Genetic distances across the whole region could best be explained by cumulative river width and geographical distance separating the populations. Within the Sundarban region, the low genetic differentiation of A. officinalis populations indicated a continuous distribution model with a smooth isolation-by-distance that gradually increased across large rivers shaping the genetic structure of A. officinalis in the Ganges Delta. These findings indicated that in addition to geographical distance, rivers might act as physical barriers, affect gene flow and shape genetic connectivity. This and detailed population genetic information should be incorporated into the ongoing afforestation or restoration strategies in and outside of the Sundarbans mangrove forest.

Mangroves are the plants adapted to strident environment with unvarying inundation of the soil and extremely diverse salinities, habitual in river banks, sand flats and coastlines of the tropics and subtropics of the world. Mangrove vegetation in six geographical regions of Kollam on the Southwest coast of India was selected to study the phytosociological characteristics and diversity indices. We analysed the pattern of mangrove species diversity, density and basal area and similarity parameters. Totally, 12 species of mangroves belonging to 8 genera and 6 families were identified; Rhizophoraceae and Avicenniaceae were the most dominant group represented. Highest density was recorded for Avicennia officinalis (3760stems/ha), followed by Avicennia marina (3721stems/ha). Avicennia officinalis is the most common mangrove counted with the highest Important value index (IVI) and Relative IVI; 64.19 and 21.40 respectively. Shannon- Weiner Index of diversity ranged from 2.002 to 3.11; species richness from 0.429 to 1.033 and the similarity in floral composition varied from 0.33 to 0.66. The sites selected were distinct from one another and the species diversity varied from one place to another; influenced by the climatic, biotic, anthropogenic stresses.

Preparation of proteins from salt-gland-rich tissues of mangrove plant is necessary for a systematic study of proteins involved in the plant's unique desalination mechanism. Extraction of high-quality proteins from the leaves of mangrove tree species, however, is difficult due to the presence of high levels of endogenous phenolic compounds. In our study, preparation of proteins from only a part of the leaf tissues (i.e. salt gland-rich epidermal layers) was required, rendering extraction even more challenging. By comparing several extraction methods, we developed a reliable procedure for obtaining proteins from salt gland-rich tissues of the mangrove species Avicennia officinalis. Protein extraction was markedly improved using a phenol-based extraction method. Greater resolution 1D protein gel profiles could be obtained. More promising proteome profiles could be obtained through 1D-LC-MS/MS. The number of proteins detected was twice as much as compared to TUTS extraction method. Focusing on proteins that were solely present in each extraction method, phenol-based extracts contained nearly ten times more proteins than those in the extracts without using phenol. The approach could thus be applied for downstream high-throughput proteomic analyses involving LC-MS/MS or equivalent. The proteomics data presented herein are available via ProteomeXchange with identifier PXD001691.

The Sunderban Biosphere Reserve of southern West Bengal, India offers an ideal locale where Hyperspectral Remote Sensing may be applied for mapping diverse range of mangrove plantations that are unique to this pristine ecological system. This delta is characterized by both ‘pure’ and ‘mixed’ mangrove forest patches where photons interact with multiple species within the instantaneous field of view of the hyperspectral sensor, and multiple scattering between the vegetation canopies becomes significantly nonlinear. This paper attempts to apply the principle of multiple scattering of light in naturally occurring conditions and see how best they describe the resultant mixed spectra for certain endmember distributions. It is observed that natural forests, mixed mangrove forest in this case, are better suited for non-linear scattering models as compared to linear models. The non-linear model has successfully identified areas of interaction of mangrove mixtures such as ceriops-excoecaria-phoenix, excoecaria- avicennia alba avicennia officinalis etc. in the study area.

The Indian Sundarbans region at the apex of the Bay of Bengal in Eastern India is impacted by industrial and urban development, including the discharge of large volumes of wastewater. We analyzed the concentrations of zinc (Zn), copper (Cu) and lead (Pb) in the root, stem and leaves of four dominant mangrove species, Avicennia officinalis, Avicennia marina, Avicennia alba and Excoecaria agallocha in samples collected from 12 different monitoring stations in the Indian Sundarbans. At all of the stations, the magnitude of accumulation of the metals in the vegetative parts of the mangroves was in the order, root > stem > leaf. The maximum concentrations of zinc in the roots (116.1 ± 4.2 μg/g dry weight) and the stems (100.4 ± 6.2 μg/g dry weight) was observed in A. officinalis collected at the Kakdwip site, whereas in leaf tissues, the maximum mean zinc concentration (66.8 ± 3.5 μg/g dry weight) was observed in A. marina collected at the Chemaguri site. The concentrations of copper were lower, with the maximum mean concentration (51.1 ± 3.0 μg/g dry weight) in the roots of A. officinalis at Kakdwip. In all vegetative parts, the concentrations of lead were lowest relative to the other metals, with the maximum mean concentration (30.4 ± 2.0 μg/g dry weight) observed in the roots of A. officinalis at Kakdwip. The concentrations of metals were generally lower in the vegetative parts of E. agallocha relative to the other mangrove species. Simultaneous analysis of dissolved metals in the surface waters at the monitoring stations revealed that zinc was present in high concentration, followed by copper and lead. Among the 12 selected stations, the highest concentrations of dissolved zinc, copper and lead were observed at Kakdwip at concentrations of 668.5 ± 5.4, 176.3 ± 4.6 and 48.4 ± 3.1 μg/L, respectively. This site is located in the western part of the Indian Sundarbans. The site at Bagmara in the eastern part of the study area had the lowest concentrations of dissolved heavy metals, as well as the lowest concentrations of the metals in sediments. High metal concentrations in sediments observed at the Frasergunj site (117.3 ± 4.3 μg/g dry weight for zinc, 37.7 ± 2.4 μg/g dry weight for copper and 10.8 ± 1.0 μg/g dry weight for lead) may be due to the presence of a fish landing station at this site. There were significant correlations between the levels of the metals in ambient media (i.e. water, sediments) and the concentrations of the metals in the vegetative parts of the mangroves; indicating that the levels of metals in mangroves reflect environmental exposures. The results indicate that mangrove species can accumulate these metals from the marine environment to ppm concentrations. Bioaccumulation factors for A. officinalis vegetation relative to sediment appeared to be >1 for lead, which is discussed in the context of using this species for bioremediation; a new dimension in the spectrum of ecosystem services offered by the mangroves.

Mangroves are a group of halophytic, evergreen, woody plants and shrubs that occupy the intertidal zone. The Jaffna peninsula has some of the major mangrove sites in Sri Lanka with large extents of undisturbed mangroves. As a result of the three-decade long armed conflict that prevailed in the entire northern part of the Island, mangrove diversity and distribution has never been evaluated since 1969. The objective of the present study was to identify the mangrove species and their distribution in the Jaffna peninsula. Five locations were selected based on the distribution of mangrove vegetation. These are Mandaitivu (East and West), Sirudivu, Kuruchidivu, Kurikadduwan, and Kaluthaipiddi. Random quadrat method was used to assess the abundance of mangrove species in the area. A total of 21 species of true mangrove plants have been recorded in Sri Lanka and the present study identified seven (07) species in the Jaffna peninsula. These are Bruguiera cylindrica, Avicennia marina, Avicennia officinalis, Rhizophora mucronata, Excoecaria agallocha, Lumnitzera racemosa, and Ceriops tagal. A mangrove associate, Acanthus ilicifolius was also recorded. Of these, Bruguiera cylindrica is a species with restricted distribution. In the present study it was recorded only from Sirudivu (density 169/km2). Avicennia marina is the dominant species on the Islands and Southern coastal line. The island of Mandaitivu had a high density of this species (293/km2 on East and 1208/km2 on West Mandaitivu). Kuruchidivu also had a higher density (2571/km2) of this species compared to other island areas. Avicennia officinalis was restricted to Sirudivu and Kuruchidivu (density 246/km2 and 100/km2 respectively). Mangroves are one of the most diverse ecosystems and they provide suitable habitats for a large number of migratory bird species and other aquatic species such as fishes, shrimps, crabs, etc. which are important to marine fisheries in Sri Lanka. They are one of the most productive ecosystems on the earth. The mangroves also protect the coasts from the impacts of storms. The study area has large extents of relatively undisturbed mangroves, found mainly on the Eastern side of the Jaffna peninsula along with the lagoon line and the Southern part of the peninsula along the coastal line. Hence the present area has a considerable conservation value. Keywords: True mangroves, Mangrove associates, Distribution, Islands, Jaffna Peninsula

Astaxanthin level of dominant mangrove floral species in Indian sundarbansThe astaxanthin level in the leaves of five dominant mangrove species sampled from twodifferent stations of Sager Island in western Indian Sundarbans region was studied during April The two sampling stations selected at the northern and southern tips of theisland exhibited drastic variation with respect to aquatic salinity although other parameters like surface water temperature pH D O and nutrients were more or less uniform Relatively higher astaxanthin level was observed in the high saline zone southern tip of the island which indicates the regulation of astaxanthin level in the mangrove plants byambient aquatic salinity The inundated leaves of the selected mangrove plants showed more astaxanthin level in comparison to the exposed ones The astaxanthin content of themangrove leaves was in the order Heritiera fomes gt Avicennia alba gt Avicennia marina gt Avicennia officinalis gt Sonneratia apetala in both the sampling stations which points towards the species specificity of the carotenoid pigment

Mangrove forests are a valuable economic resource as important breeding grounds and nursery sites for various animal species, stabilizing coastal lands and offering protection against storms, tsunamis, and sea level rise. Mangrove forest growing along the coastline of Serewe Gulf. The Serewe Gulf has great potential in tourism and sea cultivation sector. The research was conducted in the Serewe Gulf of Lombok Island, West Nusa Tenggara for 2 months (November up to December 2016). The objective of this research is to determine the diversity of mangrove in the Serewe Gulf, Lombok Island, West Nusa Tenggara using belt transect method. The identification result shows that there are 9 families with 9 types such as Rhizophoraceae (Rhizophora mucronata), Avicenniaceae (Avicennia officinalis), Sonneratiaceae (Sonneratia alba), Casuarinaceae (Casuarina equisetifolia), Bignoniaceae (Dilochnadrone sthaceae), Malvaceae (Hibiscus tiliaceus), Lythraceae (Pemphis adicula), Aizoaceae (Sesivium portulacastrum), and Euphorbiaceae (Ricinus communis). The diversity of mangrove types in the research area is in medium rate with H’ index of 1.668.

Avicennia officinalis is a medicinal mangrove plant and used in traditional folk medicine for treatment of various ailments. In the present study, the antidiabetic and antioxidant activities of petroleum ether and aqueous extracts of leaves of A. officinalis were evaluated. The antidiabetic activity was evaluated out by α-amylase and α-glucosidase inhibition study and antioxidant capacity by DPPH, superoxide and hydrogen peroxide scavenging activity of leaf extracts at various concentrations. The maximum antidiabetic activity was observed in 1.0 mg/ml of leaves extract of aqueous extracts. The maximum superoxide and hydrogen peroxide scavenging activity were exhibited by aqueous extracts with IC50 values of 0.27 and 0.17 mg/ml respectively and maximum DPPH scavenging activity was shown by petroleum ether extracts with IC50 value of 0.25 mg/ml. The qualitative and quantitative phytochemical analysis also showed presence of different phytochemicals including phenols, flavonoids and tannins which may be attributed to their antidiabetic and antioxidant activities. Thus, the present study gives a clear evidence that leaf extracts of A. officinalis possess both antidiabetic and antioxidant activities.

Objectives: The present study was conducted aiming to identify a potent mangrove plant against Mycobacterium tuberculosis using rapid method, luciferase reporter phage (LRP) assay. Methods: Seven mangrove plants viz. , Ceriops decandra, Aegiceras corniculatum, Excoecaria agollacha,Avicennia officinalis, Rhizophora mucronata, Suaeda monoica and Sesuvium portulacastrum were collected from Pichavaram mangrove forest in the east coast of, Tamil Nadu. Hexane and methanol extracts were obtained and antimycobacterial activity was done by LRP assay at the concentration of 500 μg/ml. Mycobacterial strains viz. reference strain M. tuberculosis H 37 Rv and two clinical isolates of M. tuberculosis , one sensitive and the other resistant to Streptomycin, Isoniazid, Rifampicin and Ethambutol used for this study. Results: Methanol extract of E. agollacha showed maximum antimycobacterial activity followed by A. corniculatum and A. officinalis at 500 μg/ml concentration. The remaining four plants ( Suaeda monoica , Sesuvium portulacastrum , R. mucronata and C. decandra ) showed less or no activity. However, hexane extracts of all the tested plants failed to inhibit the mycobacterial strains. Conclusions: Among the seven plants tested, E. agollacha was found to have better anti-TB activity. Further studies based on bioassay guided fractionation and phytochemical analysis may useful to identify the potent antimycobacterial molecule(s) from this mangrove plant. Asian Journal of Medical Science, Volume-5(3) 2014: 54-57 http://dx.doi.org/10.3126/ajms.v5i3.9171

Saltexclusionattherootsandsaltsecretionintheleaveswere examined in a mangrove, Avicennia officinalis. The non- secretor mangrove Bruguiera cylindrica was used for com- parative study of hydrophobic barrier formation in the roots. Bypass flow was reduced when seedlings were previously treated with high salt concentration. A biseriate exodermis was detected in the salt-treated roots,along with an enhanced deposition of hydrophobic barriers in the endodermis.These barriers reduced Na + loading into the xylem,accounting for a 90-95% salt exclusion in A. officinalis. Prominent barriers werefoundintherootsofB. cylindricaevenintheabsenceof salt treatment. A cytochrome P450 gene that may regulate suberin biosynthesis was up-regulated within hours of salt treatment in A. officinalis roots and leaves, corresponding with increased suberin deposition. X-ray microanalysis showed preferential deposition of Na + and Cl − in the root cortex compared with the stele, suggesting that the endodermisistheprimarysiteofsaltexclusion.Enhancedsalt secretion and increased suberin deposition surrounding the saltglandswereseenintheleaveswithsalttreatment.Overall, these data show that the deposition of apoplastic barriers increases resistance to bypass flow leading to efficient salt exclusion at the roots in mangroves.

The aim of the study was to determine growth performance of planted mangroves at three beats of Mirersarai forest range in the Chittagong coastal afforestation division, Bangladesh. This 22–29-year-old mangrove plantation showed satisfactory growth and regeneration with variations among different study sites. The study revealed that individual species density and overall density (stem/ha) in the study sites varied significantly (p ≤ 0.05) where density of Sonneratia apetala was maximum among five species followed by Excoecaria agallocha, Avicennia officinalis, Ceriops decandra and Bruguiera sexangula. Sonneratia apetala attained the highest mean diameter at breast height (DBH) (cm) and height (m) among all the plantation species. It was found dominant at the middle section plantations of three beats, whereas Bruguiera sexangula and Ceriops decandra were found absent at seaside plantation sites. Overall tree density was found to be highest at the middle part (1880 stem/ha) followed by inland (1610 stem/ha)...

Anthropogenic activities have always been the cause of most environmental degradation, and mangrove disappearance is no exception. A comparative assessment on the biodiversity of natural and degraded mangrove forests has been undertaken, looking at the biomass, both above-ground and below-ground. The natural and the degraded mangrove forests were situated at Kuala Selangor and Sungai Haji Dorani, respectively, both on the West coast of Peninsular Malaysia. A random sample scheme with quadrate sample plots (10 m × 10 m) was adopted for the measurement of the diameter at breast height and total height of individual tree species at both forests. Diversity indices and above- and below-ground biomass were estimated from this inventory. Eight mangrove tree species were identified at both study areas, namely: Bruguiera parviflora, Avicennia officinalis, Rhizophora mucronata, Sonneratia alba, Avicennia marina, Bruguiera cylindrica, Xylocarpus mekongensis and Excoecaria agallocha. The mangrove species in Sungai Haji Dorani showed high diversity with a Shannon–Weiner Index (H′) value of 0.91, compared to the natural mangrove of Kuala Selangor which has a lower value, H′ = 0.55. The dominant species in the natural mangrove area was B. parviflora, with the highest Important Value Index (IVI) of 70.96 %, as opposed to A. marina which was the most common species in the degraded mangrove area, with IVI of 49.16 %. An estimate of 305.46 t/ha of above-ground biomass was calculated for the natural mangrove, while 122.78 t/ha was obtained for the degraded mangrove forest. This contrasts with the below-ground biomass estimates, which were 14.09 t/ha for the natural mangrove and 36.35 t/ha for the degraded mangrove.

This study was conducted to assess the species diversity and carbon sequestration potential of a natural mangrove stand in Botoc, Pinabacdao, Samar, the Philippines. Using the quadrat sampling technique, 12 plots with a size of 100 m2 were established to facilitate inventory and measurement of trees. Shannon-Wiener index and allometric equations were used to determine species diversity, and biomass and tree carbon storage, respectively. The community's species diversity (H′ = 1.6365) was very low with a total of eight true mangrove species recorded, dominated by Avicennia officinalis with an importance value of 134.80%. Among the plots, a greater percentage of the total biomass was accounted to the above-ground biomass, corresponding to 74% (297.20 t ha−1), while the remaining 26% (103.87 t ha−1) was credited to the root biomass. The total carbon sequestered and stored in the biomass of the natural mangrove stand was 188.50 t C ha−1 equivalent to 691.81 t CO2 ha−1. The biomass and carbon density estimates...

The specialized salt glands on the epidermis of halophytic plants secrete excess salts from tissues by a mechanism that is poorly understood. We examined the salt glands as putative salt and water bi-regulatory units that can respond swiftly to altering environmental cues. The tropical mangrove tree species (Avicennia officinalis) is able to grow under fluctuating salinities (0.7-50.0 dS m(-1)) at intertidal zones, and its salt glands offer an excellent platform to investigate their dynamic responses under rapidly changing salinities. Utilizing a novel epidermal peel system, secretion profiles of hundreds of individual salt glands examined revealed that these glands could secrete when exposed to varying salinities. Notably, rhythmic fluctuations observed in secretion rates were reversibly inhibited by water channel (aquaporin) blocker, and two aquaporin genes (PIP and TIP) preferentially expressed in the salt gland cells were rapidly induced in response to increasing salt concentration. We propose that aquaporins are involved and contribute to the re-absorption of water during salt removal in Avicennia officinalis salt glands. This constitutes an adaptive feature that contributes to salt balance of trees growing in saline environments where freshwater availability is limited.

We evaluated the effects of Ralstonia solanacearum (Rs) induced biotic stress in three mangroves, viz., Avicennia officinalis, Derris trifoliata and Excoecaria agallocha. These plants were grown in pots as well as hydroponic systems with sufficient controls, and about 8 × 104 colony forming units of Rs suspension was injected into the healthy test plants (saplings). The plants were subjected to biochemical and isozyme analyses. Upon induction of Rs stress, highly significant (p 0.01) biochemical changes (%) were noticed in respect to controls: carbohydrate content was generally high (24-36) in all plants; hydroponic mangroves showed higher starch content, mangroves under hydroponic system showed increased reducing sugars (29-46), almost all mangroves showed increased protein content; phenolics showed a swing of decrease or increase between plants grown in pot and hydroponic systems; and all plants in general showed higher proline content. Regarding oxidative stress isozymes (OSE) and superoxide dismutase (EC1.15.1.1), mangroves showed 1 or 2 additional isozymes with comparable relative mobility; similarly 1 or 2 additional peroxidase (EC1.11.1.7) isozymes were found in mangroves grown under hydroponic system. Briefly, Rs induced biotic stress did not cause any wilt symptom in all the 3 mangroves tested, but their normal biochemical and OSE patterns, especially of those grown as hydroponics were elicited to significantly higher levels.

The present study deals with the investigation of erstwhile undocumented fifty four samples of West Bengal honey from ten different floral origins sesame (Sesamum indicum), hizal (Barringtonia acutangula), mustard (Brassica spp.), drumstick (Moringa oleifera), litchi (Litchi chinensis), eucalyptus (Eucalyptus spp.), karanza (Pongamia glabra), khalsi (Aegiceras corniculatum), goran (Ceriops decandra) and bain (Avicennia officinalis) for its quantification and comparison of antioxidative capacity by chemometrics. The average total polyphenol and flavonoid content of honeys varied from 9.9 ± 0.6 (bain) to 44.7 ± 2 mg (hizal) gallic acid equivalent and 5.12 ± 0.23 (drumstick) to 19.4 ± 1.38 (bain) mg of quercetin per 100 g respectively. Dark brown hizal honey with ABS450 value of 2055.6 mAU exhibited the most potent DPPH (2, 2-diphenyl-1picrylhydrazyl) radical scavenger (IC50 = 23.92 ± 1.12 mg/mL) and a FRAP (ferric reducing ability of plasma) value of 381 ± 1.9μM Fe (II).