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Madhavan C, Meera SP, Kumar A. Anatomical adaptations of mangroves to the intertidal environment and their dynamic responses to various stresses. Biol Rev Camb Philos Soc 2025; 100:1019-1046. [PMID: 39654142 DOI: 10.1111/brv.13172] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 11/23/2024] [Accepted: 11/29/2024] [Indexed: 05/31/2025]
Abstract
Mangroves are intertidal plants that survive extreme environmental conditions through unique adaptations. Various reviews on diverse physiological and biochemical stress responses of mangroves have been published recently. However, a review of how mangroves respond anatomically to stresses is lacking. This review presents major mangrove anatomical adaptations and their modifications in response to dynamic environmental stresses such as high salinity, flooding, extreme temperatures, varying light intensities, and pollution. The available research shows that plasticity of Casparian strips and suberin lamellae, variations in vessel architecture, formation of aerenchyma, thickening of the cuticle, and changes in the size and structure of salt glands occur in response to various stresses. Mangrove species show different responses correlated with the diversity and intensity of the stresses they face. The flexibility of these anatomical adaptations represents a key feature that determines the survival and fitness of mangroves. However, studies demonstrating these mechanisms in detail are relatively scarce, highlighting the need for further research. An in-depth understanding of the structural adaptations of individual mangrove species could contribute to appropriate species selection in mangrove conservation and restoration activities.
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Affiliation(s)
- Chithra Madhavan
- Department of Plant Science, Central University of Kerala, Kasaragod, Kerala, 671320, India
| | | | - Ajay Kumar
- Department of Plant Science, Central University of Kerala, Kasaragod, Kerala, 671320, India
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Meera SP, Kumar A. Role of epigenetics in mangroves: recent progress and future perspectives. PLANT & CELL PHYSIOLOGY 2025; 66:674-686. [PMID: 39916474 DOI: 10.1093/pcp/pcaf017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Revised: 01/31/2025] [Accepted: 02/04/2025] [Indexed: 06/01/2025]
Abstract
Epigenetic modifications in plants involve heritable changes in gene expression patterns that are not due to changes in gene sequences. Unlike genetic adaptations, which are long-term evolutionary changes, epigenetic modifications, such as DNA methylation, histone modifications, and noncoding RNAs, act as adaptive responses and allow plants to better cope with environmental stresses. As mangroves are uniquely located between the land and sea and remain continuously exposed to varying salinity, submergence, and hypoxia stresses, it is expected that certain epigenetic mechanisms might help them withstand the impacts of recurring stress fluctuations. Therefore, understanding the role of epigenetic regulation in mangrove stress adaptations to the intertidal environment is crucial. Despite only few studies to date having investigated epigenetic responses in mangroves, they nonetheless provide important insights into this process on which to base future research. Here, we present an update on recent progress in mangrove epigenetic research and offer perspectives on the potential roles of various epigenetic players in mangrove adaptations to the intertidal environment.
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Affiliation(s)
| | - Ajay Kumar
- Department of Plant Science, Central University of Kerala, Kasaragod, Kerala 671320, India
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Song L, Wang Q, Di Y, Wu J. Bacterial communities and interactions between macrobenthos and microorganisms after Spartina alterniflora invasion and Kandelia obovata plantation in Yueqing Bay, China. ECOHYDROLOGY & HYDROBIOLOGY 2024; 24:154-168. [DOI: 10.1016/j.ecohyd.2024.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
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Soonthornkalump S, Ow YX, Saewong C, Buapet P. Comparative study on anatomical traits and gas exchange responses due to belowground hypoxic stress and thermal stress in three tropical seagrasses. PeerJ 2022; 10:e12899. [PMID: 35186485 PMCID: PMC8840093 DOI: 10.7717/peerj.12899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/17/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The ability to maintain sufficient oxygen levels in the belowground tissues and the rhizosphere is crucial for the growth and survival of seagrasses in habitats with highly reduced sediment. Such ability varies depending on plant anatomical features and environmental conditions. METHODS In the present study, we compared anatomical structures of roots, rhizomes and leaves of the tropical intertidal seagrasses, Cymodocea rotundata, Thalassia hemprichii and Halophila ovalis, followed by an investigation of their gas exchange both in the belowground and aboveground tissues and photosynthetic electron transport rates (ETR) in response to experimental manipulations of O2 level (normoxia and root hypoxia) and temperature (30 °C and 40 °C). RESULTS We found that C. rotundata and T. hemprichii displayed mostly comparable anatomical structures, whereas H. ovalis displayed various distinctive features, including leaf porosity, number and size of lacunae in roots and rhizomes and structure of radial O2 loss (ROL) barrier. H. ovalis also showed unique responses to root hypoxia and heat stress. Root hypoxia increased O2 release from belowground tissues and overall photosynthetic activity of H. ovalis but did not affect the other two seagrasses. More pronounced warming effects were detected in H. ovalis, measured as lower O2 release in the belowground tissues and overall photosynthetic capacity (O2 release and dissolved inorganic carbon uptake in the light and ETR). High temperature inhibited photosynthesis of C. rotundata and T. hemprichii but did not affect their O2 release in belowground tissues. Our data show that seagrasses inhabiting the same area respond differently to root hypoxia and temperature, possibly due to their differences in anatomical and physiological attributes. Halophila ovalis is highly dependent on photosynthesis and appears to be the most sensitive species with the highest tendency of O2 loss in hypoxic sediment. At the same time, its root oxidation capacity may be compromised under warming scenarios.
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Affiliation(s)
- Sutthinut Soonthornkalump
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand,Coastal Oceanography and Climate Change Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Yan Xiang Ow
- St John’s Island National Marine Laboratory, Tropical Marine Science Institute, National University of Singapore, Singapore, Singapore
| | - Chanida Saewong
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand,Coastal Oceanography and Climate Change Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Pimchanok Buapet
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand,Coastal Oceanography and Climate Change Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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Mei K, Liu J, Fan J, Guo X, Wu J, Zhou Y, Lu H, Yan C. Low-level arsenite boosts rhizospheric exudation of low-molecular-weight organic acids from mangrove seedlings (Avicennia marina): Arsenic phytoextraction, removal, and detoxification. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 775:145685. [PMID: 33631581 DOI: 10.1016/j.scitotenv.2021.145685] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Arsenic (As) contamination in mangrove wetlands has become a major concern. However, the impact of As on mangroves and the rhizospheric mechanism remains unclarified. In this study, various properties and responses of mangrove seedlings were investigated after exposure to arsenite (As3+). The results indicate that low-level As promoted the secretion of Low-molecular-weight organic acids (LMWOA, 4.5-6.59 mg/kg root in dry weight) and Fe plaque formation in their rhizospheres. Citric, oxalic, and malic acid were the three main components (84.3%-86.8%). Low-level As (5 and 10 μmol/L) also inhibited the rate of radial oxygen loss (ROL) but increased the accumulation of plant As (stem > leaf > root) and plaque As (0.23-1.13 mg/kg root in dry weight). We selected model LMWOAs to further examine As migration and speciation over time in As-enriched sediments (0, 20 and 40 mg/kg). The results reveal that LMWOAs promoted sediment As mobilisation and followed the order of citric acid > malic acid > oxalic acid. The hydrolysis and precipitation of Fe3+ and the complexation with organic ligand led to aqueous As and Fe sedimentation and, conversely, increased solution pH and re-translocated free As. The tolerance mechanisms include lowering ROL, translocating As and releasing LMWOAs to reduce its toxicity, and facilitating the fixation in sediment of oxidised As. The present study highlights the fact that mangroves are potentially favourable for As phytoextraction, removal and detoxification.
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Affiliation(s)
- Kang Mei
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Jingchun Liu
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China.
| | - Jin Fan
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China; School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xin Guo
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China
| | - Jiajia Wu
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China
| | - Yi Zhou
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China
| | - Haoliang Lu
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China
| | - Chongling Yan
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China
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Liu YL, Zheng HL. Physiological and Proteomic Analyses of Two Acanthus Species to Tidal Flooding Stress. Int J Mol Sci 2021; 22:ijms22031055. [PMID: 33494455 PMCID: PMC7865619 DOI: 10.3390/ijms22031055] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 12/16/2022] Open
Abstract
The mangrove plant Acanthus ilicifolius and its relative, Acanthus mollis, have been previously proved to possess diverse pharmacological effects. Therefore, evaluating the differentially expressed proteins of these species under tidal flooding stress is essential to fully exploit and benefit from their medicinal values. The roots of A. ilicifolius and A. mollis were exposed to 6 h of flooding stress per day for 10 days. The dry weight, hydrogen peroxide (H2O2) content, anatomical characteristics, carbon and energy levels, and two-dimensional electrophoresis coupled with MALDI-TOF/TOF MS technology were used to reveal the divergent flooding resistant strategies. A. ilicifolius performed better under tidal flooding stress, which was reflected in the integrity of the morphological structure, more efficient use of carbon and energy, and a higher percentage of up-regulated proteins associated with carbon and energy metabolism. A. mollis could not survive in flooding conditions for a long time, as revealed by disrupting cell structures of the roots, less efficient use of carbon and energy, and a higher percentage of down-regulated proteins associated with carbon and energy metabolism. Energy provision and flux balance played a role in the flooding tolerance of A. ilicifolius and A. mollis.
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