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Jiang GF, Li SY, Dinnage R, Cao KF, Simonin KA, Roddy AB. Diverse mangroves deviate from other angiosperms in their genome size, leaf cell size and cell packing density relationships. ANNALS OF BOTANY 2023; 131:347-360. [PMID: 36516425 PMCID: PMC9992938 DOI: 10.1093/aob/mcac151] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS While genome size limits the minimum sizes and maximum numbers of cells that can be packed into a given leaf volume, mature cell sizes can be substantially larger than their meristematic precursors and vary in response to abiotic conditions. Mangroves are iconic examples of how abiotic conditions can influence the evolution of plant phenotypes. METHODS Here, we examined the coordination between genome size, leaf cell sizes, cell packing densities and leaf size in 13 mangrove species across four sites in China. Four of these species occurred at more than one site, allowing us to test the effect of climate on leaf anatomy. RESULTS We found that genome sizes of mangroves were very small compared to other angiosperms, but, like other angiosperms, mangrove cells were always larger than the minimum size defined by genome size. Increasing mean annual temperature of a growth site led to higher packing densities of veins (Dv) and stomata (Ds) and smaller epidermal cells but had no effect on stomatal size. In contrast to other angiosperms, mangroves exhibited (1) a negative relationship between guard cell size and genome size; (2) epidermal cells that were smaller than stomata; and (3) coordination between Dv and Ds that was not mediated by epidermal cell size. Furthermore, mangrove epidermal cell sizes and packing densities covaried with leaf size. CONCLUSIONS While mangroves exhibited coordination between veins and stomata and attained a maximum theoretical stomatal conductance similar to that of other angiosperms, the tissue-level tradeoffs underlying these similar relationships across species and environments were markedly different, perhaps indicative of the unique structural and physiological adaptations of mangroves to their stressful environments.
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Affiliation(s)
| | - Su-Yuan Li
- Guangxi Key Laboratory of Forest Ecology and Conservation, and State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi 530004, PR China
| | - Russell Dinnage
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, FL 33199USA
| | - Kun-Fang Cao
- Guangxi Key Laboratory of Forest Ecology and Conservation, and State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi 530004, PR China
| | - Kevin A Simonin
- Department of Biology, San Francisco State University, San Francisco, CA 94132USA
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Abstract
Foliar water uptake (FWU) is a mechanism that enables plants to acquire water from the atmosphere through their leaves. As mangroves live in a saline sediment water environment, the mechanism of FWU might be of vital importance to acquire freshwater and grow. The goal of this study was to assess the FWU capacity of six different mangrove species belonging to four genera using a series of submersion experiments in which the leaf mass increase was measured and expressed per unit leaf area. The foliar water uptake capacity differed between species with the highest and lowest average water uptake in Avicennia marina (Forssk.) Vierh. (1.52 ± 0.48 mg H2O cm−2) and Bruguiera gymnorhiza (L.) Lam. (0.13 ± 0.06 mg H2O cm−2), respectively. Salt-excreting species showed a higher FWU capacity than non-excreting species. Moreover, A. marina, a salt-excreting species, showed a distinct leaf anatomical trait, i.e., trichomes, which were not observed in the other species and might be involved in the water absorption process. The storage of leaves in moist Ziplock bags prior to measurement caused leaf water uptake to already occur during transport to the field station, which proportionately increased the leaf water potential (A. marina: −0.31 ± 0.13 MPa and B. gymnorhiza: −2.70 ± 0.27 MPa). This increase should be considered when performing best practice leaf water potential measurements but did not affect the quantification of FWU capacity because of the water potential gradient between a leaf and the surrounding water during submersion. Our results highlight the differences that exist in FWU capacity between species residing in the same area and growing under the same environmental conditions. This comparative study therefore enhances our understanding of mangrove species’ functioning.
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Gauthey A, Backes D, Balland J, Alam I, Maher DT, Cernusak LA, Duke NC, Medlyn BE, Tissue DT, Choat B. The Role of Hydraulic Failure in a Massive Mangrove Die-Off Event. FRONTIERS IN PLANT SCIENCE 2022; 13:822136. [PMID: 35574083 PMCID: PMC9094047 DOI: 10.3389/fpls.2022.822136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/25/2022] [Indexed: 06/15/2023]
Abstract
Between late 2015 and early 2016, more than 7,000 ha of mangrove forest died along the coastline of the Gulf of Carpentaria, in northern Australia. This massive die-off was preceded by a strong 2015/2016 El Niño event, resulting in lower precipitation, a drop in sea level and higher than average temperatures in northern Australia. In this study, we investigated the role of hydraulic failure in the mortality and recovery of the dominant species, Avicennia marina, 2 years after the mortality event. We measured predawn water potential (Ψpd) and percent loss of stem hydraulic conductivity (PLC) in surviving individuals across a gradient of impact. We also assessed the vulnerability to drought-induced embolism (Ψ50) for the species. Areas with severe canopy dieback had higher native PLC (39%) than minimally impacted areas (6%), suggesting that hydraulic recovery was ongoing. The high resistance of A. marina to water-stress-induced embolism (Ψ50 = -9.6 MPa), indicates that severe water stress (Ψpd < -10 MPa) would have been required to cause mortality in this species. Our data indicate that the natural gradient of water-stress enhanced the impact of El Niño, leading to hydraulic failure and mortality in A. marina growing on severely impacted (SI) zones. It is likely that lowered sea levels and less frequent inundation by seawater, combined with lower inputs of fresh water, high evaporative demand and high temperatures, led to the development of hyper-salinity and extreme water stress during the 2015/16 summer.
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Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Diana Backes
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jeff Balland
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Iftakharul Alam
- College of Science and Engineering, James Cook University, Cairns, QLD, Australia
| | - Damien T. Maher
- Faculty of Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Lucas A. Cernusak
- College of Science and Engineering, James Cook University, Cairns, QLD, Australia
| | - Norman C. Duke
- TropWATER Centre, James Cook University, Townsville, QLD, Australia
| | - Belinda E. Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - David T. Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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Nizam A, Meera SP, Kumar A. Genetic and molecular mechanisms underlying mangrove adaptations to intertidal environments. iScience 2022; 25:103547. [PMID: 34988398 PMCID: PMC8693430 DOI: 10.1016/j.isci.2021.103547] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mangroves are halophytic plants belonging to diverse angiosperm families that are adapted to highly stressful intertidal zones between land and sea. They are special, unique, and one of the most productive ecosystems that play enormous ecological roles and provide a large number of benefits to the coastal communities. To thrive under highly stressful conditions, mangroves have innovated several key morphological, anatomical, and physio-biochemical adaptations. The evolution of the unique adaptive modifications might have resulted from a host of genetic and molecular changes and to date we know little about the nature of these genetic and molecular changes. Although slow, new information has accumulated over the last few decades on the genetic and molecular regulation of the mangrove adaptations, a comprehensive review on it is not yet available. This review provides up-to-date consolidated information on the genetic, epigenetic, and molecular regulation of mangrove adaptive traits.
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Affiliation(s)
- Ashifa Nizam
- Department of Plant Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala 671316, India
| | - Suraj Prasannakumari Meera
- Department of Biotechnology and Microbiology, Dr. Janaki Ammal Campus, Kannur University, Palayad, Kerala 670661, India
| | - Ajay Kumar
- Department of Plant Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala 671316, India
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Hasanuzzaman M, Inafuku M, Nahar K, Fujita M, Oku H. Nitric Oxide Regulates Plant Growth, Physiology, Antioxidant Defense, and Ion Homeostasis to Confer Salt Tolerance in the Mangrove Species, Kandelia obovata. Antioxidants (Basel) 2021; 10:611. [PMID: 33923816 PMCID: PMC8073094 DOI: 10.3390/antiox10040611] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 01/29/2023] Open
Abstract
Facultative halophyte Kandelia obovata plants were exposed to mild (1.5% NaCl) and severe (3% NaCl) salt stress with or without sodium nitroprusside (SNP; 100 µM; a NO donor), hemoglobin (Hb, 100 µM; a NO scavenger), or Nω-nitro-L-arginine methyl ester (L-NAME, 100 µM; a NO synthase inhibitor). The plants were significantly affected by severe salt stress. They showed decreases in seedling growth, stomatal conductance, intercellular CO2 concentration, SPAD value, photosynthetic rate, transpiration rate, water use efficiency, and disrupted antioxidant defense systems, overproduction of reactive oxygen species, and visible oxidative damage. Salt stress also induced ion toxicity and disrupted nutrient homeostasis, as indicated by elevated leaf and root Na+ contents, decreased K+ contents, lower K+/Na+ ratios, and decreased Ca contents while increasing osmolyte (proline) levels. Treatment of salt-stressed plants with SNP increased endogenous NO levels, reduced ion toxicity, and improved nutrient homeostasis while further increasing Pro levels to maintain osmotic balance. SNP treatment also improved gas exchange parameters and enhanced antioxidant enzymes' activities (catalase, ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase). Treatment with Hb and l-NAME reversed these beneficial SNP effects and exacerbated salt damage, confirming that SNP promoted stress recovery and improved plant growth under salt stress.
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Affiliation(s)
- Mirza Hasanuzzaman
- Molecular Biotechnology Group, Center of Molecular Biosciences (COMB), Tropical Biosphere Research Center, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan;
- Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka 1207, Bangladesh
| | - Masashi Inafuku
- Molecular Biotechnology Group, Center of Molecular Biosciences (COMB), Tropical Biosphere Research Center, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan;
| | - Kamrun Nahar
- Department of Agricultural Botany, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka 1207, Bangladesh;
| | - Masayuki Fujita
- Laboratory of Plant Stress Responses, Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan;
| | - Hirosuke Oku
- Molecular Biotechnology Group, Center of Molecular Biosciences (COMB), Tropical Biosphere Research Center, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan;
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Effects of Salt on Root Aeration, Nitrification, and Nitrogen Uptake in Mangroves. FORESTS 2019. [DOI: 10.3390/f10121131] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The potential effects of salt on the growth, root anatomy, radial oxygen loss (ROL), and nitrogen (N) dynamics in mangroves were investigated using the seedlings of Avicennia marina (Forsk.) Vierh. The results showed that a moderate salinity (200 mM NaCl) appeared to have little negative effect on the growth of A. marina. However, higher salt stresses (400 and 600 mM NaCl) significantly inhibited the biomass yield. Concentrations of N in the roots and leaves decreased sharply with increasing salinity. Nevertheless, the presence of salt directly altered root anatomy (e.g., reduced root porosity and promoted suberization within the exodermis and endodermis), leading to a significant reduction in ROL. The results further showed that reduced ROL induced by salt could restrain soil nitrification, resulting in less ammonia-oxidizing archaea and bacteria (AOA and AOB) gene copies and lower concentrations of NO3− in the soils. While increased root suberization induced by salt inhibited NH4+ and NO3− uptake and influx into the roots. In summary, this study indicated that inhibited root aeration may be a defense response to salt, however these root symptoms were not advantageous for rhizosphere nitrification and N uptake by A. marina.
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Quadros AF, Zimmer M. Dataset of "true mangroves" plant species traits. Biodivers Data J 2018:e22089. [PMID: 29362554 PMCID: PMC5769720 DOI: 10.3897/bdj.5.e22089] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/29/2017] [Indexed: 12/02/2022] Open
Abstract
Background Plant traits have been used extensively in ecology. They can be used as proxies for resource-acquisition strategies and facilitate the understanding of community structure and ecosystem functioning. However, many reviews and comparative analysis of plant traits do not include mangroves plants, possibly due to the lack of quantitative information available in a centralised form. New information Here a dataset is presented with 2364 records of traits of "true mangroves" species, gathered from 88 references (published articles, books, theses and dissertations). The dataset contains information on 107 quantitative traits and 18 qualitative traits for 55 species of "true mangroves" (sensuTomlinson 2016). Most traits refer to components of living trees (mainly leaves), but litter traits were also included.
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Affiliation(s)
| | - Martin Zimmer
- Leibniz Centre for Tropical Marine Research, Bremen, Germany
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