Search Results (20)

To understand the mechanisms underlying species assemblage along salt gradients in intertidal zones, we measured the xylem hydraulic vulnerability curves (HVCs), leaf water potential (ψ), stomatal conductance (g_s), specific leaf area (SLA), and wood density (WD) for six mangrove species of Avicennia marina, Bruguiera gymnorrhiza, Aegiceras corniculatum, Kandelia obovata, Sonneratia apetala, and Sonneratia caseolaris. We found the following: (1) A. marina and B. gymnorhiza had the most negative P₅₀ (water potential at which 50% of hydraulic conductivity was lost), while S. caseolaris and S. apetala had the least negative P₅₀, indicating different resistance to embolism in xylem; (2) P₅₀ and P₈₈ (water potential at which 88% of hydraulic conductivity was lost) declined with increasing salinity from the onshore to offshore species, as their water regulation strategy meanwhile transitioned from isohydry to anisohydry; (3) B. gymnorhiza had smaller SLA but larger hydraulic safety margin (HSM), implying potentially higher capacity of water retention in leaves and lower risk of hydraulic failure in xylem. These results suggest that hydraulic traits play an important role in shaping the salt-driven niche segregation of mangroves along intertidal zones. Our research contributes to a more comprehensive understanding of the hydraulic physiology of mangroves in salt adaption and may facilitate a general modeling framework for examining and predicting mangrove resilience to a changing climate. Full article

The golden apple snail (GAS, Pomacea canaliculata) has invaded mangrove forests. The effect of water contaminated by metabolic activity of GAS feeding on Acanthus ilicifolius (T1), Sonneratia apetala (T2), and without food (CK) on the native mangrove black helmet snail (BHS, Neritina pulligera) was investigated under salinity conditions. The GAS deteriorated saline water quality (2.5‰). DO contents in T1 and T2 approached zero at 9 d. Compared to CK, the contents of COD, total N, NH₄⁺, NO₃⁻, and total P of the contaminated water in T1 increased by 297%, 205%, 262%, 210%, and 518% after 9 d, while these indicators in T2 increased by 74%, 31%, 57%, 326%, and 154%, respectively. The LC₅₀ of the contaminated water in T1 against the BHS reached 22.72%. The weight of the BHS exposed to the 100% contaminated water in T1 and T2 significantly decreased after exposure. The content of GPT of the BHS exposed to the 100%-contaminated water in T1 and T2 increased by 55% and 26%, while the MDA content increased by 38% and 34%. The 100%-contaminated water in T1 led to cell degeneration and incomplete structure in the hepatopancreas tissue of the BHS. The GAS feeding on holly mangroves can compete against native mangrove snails through water deterioration. Full article

Mangroves play a crucial role in supporting the biodiversity of coastal wetlands, acting as a vital link between terrestrial and marine ecosystems. In mainland China, Sonneratia apetala, an invasive mangrove species, has recently become dominant in these environments. While it contributes to the stability of mangrove ecosystems and is widely used in coastal restoration efforts, its rapid growth poses a significant threat to the survival of native mangrove species. However, the spatiotemporal growth dynamics and landscape impacts of Sonneratia apetala remain underexplored in scholarly research. This study employs remote sensing and GIS techniques to analyze the growth patterns of Sonneratia apetala over a 14-year period along the eastern coast of the Leizhou Peninsula in China. The analysis revealed the following key findings: (1) The mangrove area expanded from 274.17 hm² to 383.42 hm², with an average annual growth rate of 2.84%. (2) The area of Sonneratia apetala increased from 115.15 hm² in 2010 to 254.81 hm² in 2023, with an average annual growth rate of 1.29%. The area of local mangrove species declined from 163.02 hm² to 125.06 hm² (a decrease from 22.11% to 16.96%), with an average annual growth rate of −1.66%. (3) The number of Sonneratia apetala patches increased from 139 to 324, while the area-weighted shape index rose from 3.4 to 7.81. The decline of native mangrove species, driven by the rapid spread of Sonneratia apetala, suggests that this species is encroaching on native mangrove habitats. Through geospatial analysis, this study provides valuable insights into how introduced species can reshape mangrove landscape structures and the broader implications for regional biodiversity. These findings clearly demonstrate that Sonneratia apetala is encroaching upon local mangrove habitats, highlighting the urgent need for strategic management and conservation efforts to mitigate the ecological impacts of the proliferation of this species. Furthermore, this research is important for coastal sustainability management strategies that balance ecological restoration with the preservation of native biodiversity, ensuring long-term ecosystem health and resilience. Full article

Sonneratia apetala Buch., an alien species with strong growth and adaptability, has been introduced and cultivated in Southeastern China. Meanwhile, Derris trifoliata Lour., native to coastal and riparian areas in Guangdong, Guangxi, and Fujian provinces, has experienced a rapid surge in population, impacting the health of mangrove ecosystems. Our research focuses on understanding the interactions between Oriental mangroves and D. trifoliata, particularly their proliferation and long-term symbiotic relationships. We investigated how Oriental mangrove proliferation promotes excessive D. trifoliata growth and explored the underlying mechanisms. In Leizhou Bay, Guangxi, the annual growth rate surged from 12.03% (2005–2015) to 55.36% (2015–2019), indicating a significant acceleration post-2015 and a concerning trend towards overgrowth. D. trifoliata failed to produce seeds on sea rockets or bulrushes, instead yielding 10.5 and 97.43 seeds/m² on native red mangroves and Oriental mangroves, respectively. Along riverbanks, 68% of Oriental mangroves hosted D. trifoliata, and the suitable regions for these species overlapped significantly. Oriental mangroves reach 15 m tall with 10 × 10 m crown diameters, providing ample vine space, optimal photosynthesis conditions, sturdy support, and convenient dispersal routes. This study offers insights into introduced–native species interactions in mangrove ecosystems, with significance for management and preservation. Full article

Mangroves play a substantial role in the global carbon cycle and are highly productive. To evaluate the effectiveness of a remote-sensing image in mangrove-species classification and carbon stock assessment, we utilized Worldview-3 images to map the mangrove species in Qi’ao Island, Guangdong Province, China, using a Random Forest classifier. We compared the contribution of spectral features, derivation features, and textural features to the classification accuracy and found that textural features significantly improved the overall accuracy, achieving 92.44% with all features combined. According to field-survey results, the main mangrove species in Qi’ao Island were Sonneratia apetala (SA), Acanthus ilicifolius (AI), Kandelia candel (KC), Acrostichum aureum (AA), Aegiceras corniculatum (AC), and Heritiera littoralis (HL); there are also many reeds mixed with mangroves. According to classification results, the total area of the mangroves and reeds is about 451.86 ha; the SA was the dominant species with an area of 393.90 ha. We calculated the total carbon stock of mangroves on Qi’ao Island by integrating the area of different species and their average total carbon density for the first time. The total carbon stock of mangroves in Qi’ao Island is between 147.78–156.14 kt, which demonstrates the significant potential of mangroves in carbon sequestration. Full article

Sonneratia apetala is an essential mangrove wetland restoration tree species. Studying its molecular mechanism for salt tolerance could lay a foundation for further cultivating excellent resistant germplasm. This study used a combination of PacBio isoform sequencing (Iso-seq) and BGISEQ RNA sequencing (RNA-seq) to analyze the molecular mechanism to salt stress response of one-year-old S. apetala leaves. The growth and physiological analysis showed that physiological indexes such as growth rate, net photosynthetic rate and antioxidant enzyme activity all exhibit significant changes under salt stress. From Iso-seq, a total of 295,501 full-length transcripts, with an average length of 1418 bp, were obtained. RNA-seq produced 4712 differentially expressed genes (DEGs) as compared to a control group. Of these, 930 were identified to be co-expressed during the STEM time sequence analysis. Further, 715 and 444 co-expressed DEGs were annotated by GO and KEGG analyses, respectively. Moreover, 318 of the co-expressed DEGs were annotated as essential genes that were implicated in salt stress response of S. apetala, which were involved in transcription factors, signal transduction, hormone response, ROS homeostasis, osmotic balance, cell wall synthesis or modification. These results provide candidate targets for further characterization and offer insights into the salt-tolerant mechanism of S. apetala. Full article

Invasive species have had substantial impacts on global mangrove forests. Apple snails (Pomacea canaliculata) have invaded mangrove forests in China. To clarify the potential detritivorous diet of P. canaliculata, the growth and feeding indicators of invasive juvenile snails collected from mangroves in Guangzhou, China, were studied using decaying leaf litter from five mangrove species, including Acanthus ilicifolius, Acrostichum aureum, Kandelia candel, Aegiceras corniculatum, and Sonneratia apetala. The growth indicators of the survival ratio and specific growth rate were calculated by measuring the live weight of the snails and the number of dead snails after 30 days. The feeding indicator of the weight-specific daily feeding rate (WDR) was calculated by measuring the snail weight and the amount of leaf litter ingested after 120 h. A multiple-choice experiment was performed on the snails by providing the decaying leaf species together, while a no-choice experiment was performed using a single species of decaying leaf litter. The survival and specific growth ratio of P. canaliculata feeding on decaying leaf litter of A. ilicifolius were higher than those for A. aureum. The WDR values of P. canaliculata feeding on the decaying leaf litter of A. ilicifolius and S. apetala were both significantly higher than those for A. corniculatum, A. aureum, and K. candel. The lowest WDR value of P. canaliculata feeding on decaying leaf litter was observed for A. aureum in the no-choice experiment. P. canaliculata mainly fed on decaying leaf litter of A. ilicifolius and S. apetala. The phosphorous contents and ash of the decaying leaf litter positively affected the WDR values of P. canaliculata obtained in the multiple-choice and no-choice experiments. The contents of lignin, tannin, and flavonoid negatively affected the WDR values of P. canaliculata. The potential diet of invasive P. canaliculata in mangroves was closely tied to the chemical characteristics of the decaying leaf litter. P. canaliculata can invade A. ilicifolius and/or S. apetala mangroves by utilizing the debris on the mangrove ground. Understanding the potential detritivorous diet of P. canaliculata in invaded mangroves can help us to assess this species’ dispersal risk and provide support for mangrove management. Full article

This study focuses on the nitrogen removal capability of the mangrove wetland system towards resolving the excessive inorganic nitrogen content in the marine water of Shenzhen’s Deep Bay. The nitrogen distribution characteristics, biological nitrogen removal processes, nitrogen removal functional genes, and bacterial community characteristics were investigated in five wetland sites in the intertidal zone of the Deep Bay, viz. the Kandelia candel, Bruguiera gymnorrhiza, Sonneratia apetala, Aegiceras corniculatum, and mud flat sites. The results showed that ammonia and nitrate in the marine water were significantly removed in the five wetlands sites, with respective removal efficiencies of 70.9–75.5% and 89.5–94.0%. The concentration of ammonia and nitrate in pore water remained significantly unchanged with depth. Denitrification and anammox were each system’s main biological nitrogen removal processes, and their rates were 1.70–3.22 and 0.07–0.36 μmol/(kg·h), respectively. The denitrification rates in the mangroves were higher than in the mud flat site, unlike the anammox rates. The denitrifying functional genes (nirS, nosZ) and anammox functional gene (hzsB) showed an excellent linear relationship with the relevant process rates. Bacillus and Pseudomonas were the main heterotrophic denitrifying bacteria genera identified. The autotrophic denitrifying bacteria genus Sulfurovum was also identified in the systems, while Candidatus Scalindua was the only anammox genus identified in this study. The results of this study improve our understanding of the nitrogen removal characteristics of coastal wetlands and the role of mangrove plants in the biological nitrogen removal processes. Full article

Mangroves are the only forests located at the sea–land interface in tropical and subtropical regions. They are key elements of tropical coastal ecosystems, providing numerous ecosystem services. Among them is the production of specialized metabolites by mangroves and their potential use in agriculture to limit weed growth in cultures. We explored the in vitro allelopathic potential of eight mangrove species’ aqueous leaf extracts (Avicennia marina, Kandelia obovata, Bruguiera gymnorhiza, Sonneratia apetala, Sonneratia caseolaris, Aegiceras corniculatum, Lumnitzera racemosa and Rhizophora stylosa) on the germination and growth of Echinochloa crus-galli, a weed species associated with rice, Oryza sativa. Leaf methanolic extracts of mangrove species were also studied via UHPLC-ESI/qToF to compare their metabolite fingerprints. Our results highlight that A. corniculatum and S. apetala negatively affected E. crus-galli development with a stimulating effect or no effect on O. sativa. Phytochemical investigations of A. corniculatum allowed us to putatively annotate three flavonoids and two saponins. For S. apetala, three flavonoids, a tannin and two unusual sulfated ellagic acid derivatives were found. Some of these compounds are described for the first time in these species. Overall, A. corniculatum and S. apetala leaves are proposed as promising natural alternatives against E. crus-galli and should be further assessed under field conditions. Full article

Toxic metal pollution is a global issue, and the use of metal-accumulating plants to clean contaminated ecosystems is one of the most rapidly growing ecologically beneficial and cost-effective technologies. In this study, samples of sediment and three mangrove species (Excoecaria agallocha, Avicennia officinalis, Sonneratia apetala) were collected from the world’s largest mangrove forest (along the Northern Bay of Bengal Coast) with the aim of evaluating metal concentrations, contamination degrees, and phytoremediation potentiality of those plants. Overall, the heavy metals concentration in sediment ranged from Cu: 72.41–95.89 mg/kg; Zn: 51.28–71.20 mg/kg; Fe: 22,760–27,470 mg/kg; Mn: 80.37–116.37 mg/kg; Sr: 167.92–221.44 mg/kg. In mangrove plants, the mean concentrations were in the order of E. agallocha > A. officinalis > S. apetala. The mean (± SD) concentration of each metal in the plant tissue (root) was found following the descending order of Fe (737.37 ± 153.06) > Mn (151.13 ± 34.26) > Sr (20.98 ± 6.97) > Cu (16.12 ± 4.34) > Zn (11.3 ± 2.39) mg/kg, whereas, in the leaf part, the mean concentration (mg/kg) of each metal found in the order of Fe (598.75 ± 410.65) > Mn (297.27 ± 148.11) > Sr (21.40 ± 8.71) > Cu (14.25 ± 2.51) > Zn (12.56 ± 2.13). The contamination factor (CF) values for the studied metals were in the descending order of Cu > Sr > Zn > Fe > Mn. The values of I_geo (Geo-accumulation index) and CF showed that the area was unpolluted to moderately polluted by Zn, Fe, Mn, Cu and Sr. Enrichment factor (EF) values in both sampling stations portrayed moderate to minimum enrichment. Phytoremediation potentiality of the species was assessed by bio-concentration factor (BCF) and translocation factor (TF). BCF values showed less accumulation for most of the heavy metals (<1) except Mn which was highly accumulated in all mangrove plants. The translocation factor (TF) values depicted that most of the heavy metals were strongly accumulated in plant tissues (>1). However, the BCF value depicts that Mn was highly bioconcentrated in E. agallocha, but the translocation on leaves tissue were minimum, which reveals that E. agallocha is phytoextractor for Mn, and accumulated in root tissues. All the examined plants can be used as phytoextractors as they have bioconcentration factors <1 and translocation factors >1. However, A. officinalis is clearly more suitable for metal extraction than S. apetala and E. agallocha in terms of hyper-metabolizing capabilities. Full article

To rapidly rehabilitate mangrove forests, exotic mangrove species characterized by high growth rates have been introduced in China, which would undoubtedly affect the nutrient status, nutrient acquisition and utilization strategies of mangrove plants, but the mechanism remains unclear. Qi’ao Island (a suburb of Zhuhai City) has the largest continuous exotic mangrove forests in China, where a mass collection of mangrove soils, plant tissues and tidewater was conducted. Ecological stoichiometric ratios and isotopic compositions were then analyzed to evaluate the ecosystem-scale nutrient status and compare the nutrient acquisition and utilization strategies of native Kandelia obovata (KO) and exotic Sonneratia apetala (SA) species. Soil and foliar C:N:P stoichiometries indicated that there is high P availability but N limitations, while further isotopic evidence indicated that native KO and exotic SA responded differently to the N limitation status. First, native KO seemed to prefer NO₃⁻, while exotic SA preferred NH₄⁺, according to the Δ¹⁵N_leaf–root (leaf–root δ¹⁵N difference) as well as the relationships between foliar δ¹⁵N and soil-extracted NH₄⁺ δ¹⁵N, and between N and heavy metal contents. This suggested possible inter-specific competition between native KO and exotic SA, leading to different N species’ preferences to maximize resource utilization. Next, native KO likely adopted the “conservative” strategy to ensure survival with reduced investment in N-rich growth components but root systems leading to lower growth rates and higher N use efficiency (NUE) and intrinsic water use efficiency (iWUE), while exotic SA adopted the “aggressive” strategy to ensure fast growth with heavy investment in N-rich growth components, leading to rapid growth and lower NUE and iWUE, and showing signs of invasiveness. Further, native KO is more responsive to aggravated N limitation by enhancing NUE. This study will provide insights into the adaptation of different mangrove species to nutrient limitations and the risks associated with large-scale plantations of exotic mangrove species. Full article

Mangrove forests are increasingly threatened by plant invasions worldwide, but some mangrove species are invasive and threaten salt marsh and native mangrove ecosystems. The southern coast of China is invaded by the cordgrass Spartina alterniflora, and the mangrove Sonneratia apetala, providing a model system for studying the processes and mechanisms through which non-native species establish and spread. We used a transplant experiment to test the overarching hypothesis that native herbivores and plants provided biotic resistance against invasion by S. apetala, and that the importance of these factors would vary geographically. Survival of transplanted mangrove seedlings was lower in Zhangjiang Estuary (23°55′ N) than in Leizhou Bay (20°56′ N), and varied with species and habitats. S. apetala had higher survival and growth rates than native mangroves at both sites, and S. apetala grew taller than the S. alterniflora canopy at Leizhou Bay in only two growing seasons. In contrast, native mangroves grew poorly in S. alterniflora. Grazing by rodents and insects suppressed the growth and survival of Kandelia obovata and Avicennia marina in Zhangjiang Estuary and Leizhou Bay, but had little effect on S. apetala. Competition with vegetation (S. alterniflora and native mangroves) exacerbated the reduced survival of native mangroves, and these effects varied across study sites. Low survival of non-native S. apetala in vegetated habitats at Zhangjiang Estuary was likely due to a synergistic effect of low winter temperatures and low light intensity. Escape from herbivory (the opposite to biotic resistance) and fast growth may drive the quick expansion of non-native S. apetala in China. Rapid encroachment of S. apetala may transform the native mangrove forests and monospecific intertidal Spartina grasslands into non-native mangrove forests in the southern coast of China. Full article

Aging is related to the lowered overall functioning and increased risk for various age-related diseases in humans. Sonneradon A (SDA), a new compound first extracted from the edible fruits of mangrove Sonneratia apetala, showed remarkable antiaging activity. However, the role of SDA in antiaging remains unclear. In this article, we studied the function of SDA in antiaging by using the animal model Caenorhabditis elegans. Results showed that SDA inhibited production of reactive oxygen species (ROS) by 53%, and reduced the accumulation of aging markers such as lipids and lipofuscins. Moreover, SDA also enhanced the innate immune response to Pseudomonas aeruginosa infection. Genetic analysis of a series of mutants showed that SDA extended the lifespan of the mutants of eat-2 and glp-1. Together, this effect may be related to the enhanced resistance to oxidative stress via mitochondrial and insulin/insulin-like growth factor-1 signaling (IIS) pathways. The results of this study provided new evidence for an antiaging effect of SDA in C. elegans, as well as insights into the implication of antiaging activity of SDA in higher organisms. Full article

Even though survival rates for mangrove restoration in Vietnam have often been low, there is no information on fungal pathogens associated with mangrove decline in Vietnam. Therefore, this research was undertaken to assess the overall health of mangrove afforestation in Thanh Hoa Province and fungal pathogens associated with tree decline. From a survey of 4800 Sonneratia trees, the incidence of disorders was in the order of pink leaf spot > shoot dieback > black leaf spot for S. caseolaris and black leaf spot > shoot dieback > pink leaf spot for S. apetala. Approximately 12% of S. caseolaris trees had both pink leaf spot and shoot dieback, while only 2% of S. apetala trees had black leaf spot and shoot dieback. Stem and leaf samples were taken from symptomatic trees and fungi were cultured in vitro. From ITS4 and ITS5 analysis, four main fungal genera causing leaf spots and shoot dieback on the two Sonneratia species were identified. The most frequently isolated fungal taxa were Curvularia aff. tsudae (from black leaf spot),Neopestalotiopsis sp.1 (from stem dieback), Pestalotiopsis sp.1 (from pink leaf spot), and Pestalotiopsis sp.4a (from black leaf spot). The pathogenicity of the four isolates was assessed by under-bark inoculation of S. apetala and S. caseolaris seedlings in a nursery in Thai Binh Province. All isolates caused stem lesions, and Neopestalotiopsis sp.1 was the most pathogenic. Thus, investigation of fungal pathogens and their impact on mangrove health should be extended to other afforestation projects in the region, and options for disease management need to be developed for mangrove nurseries. Full article

Background and Objectives: The rapid spread of invasive Spartina alterniflora Loisel. in the mangrove ecosystems of China was reduced using Sonneratia apetala Buch.-Ham. as an ecological replacement. Here, we studied the effects of invasion and ecological replacement using S. apetala on soil organic carbon fractions and stock on Qi’ao Island. Materials and Methods: Seven sites, including unvegetated mudflat and S. alterniflora, rehabilitated mangroves with different ages (one, six, and 10 years) and mature native Kandelia obovata Sheue, Liu, and Yong areas were selected in this study. Samples in the top 50 cm of soil were collected and then different fractions of organic carbon, including the total organic carbon (TOC), particulate organic carbon (POC), soil water dissolved carbon (DOC) and microbial biomass carbon (MBC), and the total carbon stock were measured and calculated. Results: The growth of S. alterniflora and mangroves significantly increased the soil TOC, POC, and MBC levels when compared to the mudflat. S. alterniflora had the highest soil DOC contents at 0–10 cm and 20–30 cm and the one-year restored mangroves had the highest MBC content. S. alterniflora and mangroves both had higher soil total carbon pools than the mudflat. Conclusions: The invasive S. alterniflora and young S. apetala forests had significantly lower soil TOC and POC contents and total organic carbon than the mature K. obovata on Qi’ao Island. These results indicate that ecological replacement methods can enhance long term carbon storage in Spartina-invaded ecosystems and native mangrove species are recommended. Full article