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Naz N, Asghar A, Basharat S, Fatima S, Hameed M, Ahmad MSA, Ahmad F, Shah SMR, Ashraf M. Phytoremediation through microstructural and functional alterations in alkali weed ( Cressa cretica L.) in the hyperarid saline desert. Int J Phytoremediation 2023; 26:913-927. [PMID: 37985450 DOI: 10.1080/15226514.2023.2282044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Salt excretory halophytes are the major sources of phytoremediation of salt-affected soils. Cressa cretica is a widely distributed halophyte in hypersaline lands in the Cholistan Desert. Therefore, identification of key physio-anatomical traits related to phytoremediation in differently adapted C. cretica populations was focused on. Four naturally adapted ecotypes of non-succulent halophyte Cressa cretica L. form hyper-arid and saline desert Cholistan. The selected ecotypes were: Derawar Fort (DWF, ECe 20.8 dS m-1) from least saline site, Traway Wala Toba (TWT, ECe 33.2 dS m-1) and Bailah Wala Dahar (BWD, ECe 45.4 dS m-1) ecotypes were from moderately saline sites, and Pati Sir (PAS, ECe 52.4 dS m-1) was collected from the highly saline site. The natural population of this species was collected and carefully brought to the laboratory for different structural and functional traits. As a result of high salinity, Na+, Cl-, K+, and Ca2+ content significantly increased at root and shoot level. At root level, some distinctive modifications such as increased sclerification in vascular bundles, enlarged vascular bundles, metaxylem vessels, phloem region, and storage parenchyma (cortex) are pivotal for water storage under extreme arid and osmotic condition. At the stem level, enhanced sclerification in outer cortex and vascular bundles, stem cellular area, cortical proportion, metaxylem and phloem area, and at the leaf level, very prominent structural adaptations were thicker and smaller leaves with increased density of salt glands and trichomes at surface, few and large stomata, reduced cortical and mesophyll parenchyma, and narrow xylem vessels and phloem area represent their non-succulent nature. The ecotype collected from hypersaline environments was better adapted regarding growth traits, ion uptake and excretion, succulence, and phytoremediation traits. More importantly, structural and functional traits such as root length and biomass, accumulation of toxic ions along with K+ in root and shoot, accumulation of Ca2+ in shoot and Mg2+ in root, excretion of toxic ions were the highest in this ecotype. In conclusion, all these alterations strongly favor water conservation, which certainly contributes to ecotypes survival under salt-induced physiological drought.
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Affiliation(s)
- Nargis Naz
- Department of Botany, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Ansa Asghar
- Department of Botany, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Sana Basharat
- Department of Botany, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Sana Fatima
- Department of Botany, The Government Sadiq College University, Bahawalpur, Pakistan
| | - Mansoor Hameed
- Department of Botany, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | | | - Farooq Ahmad
- Department of Botany, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Syed Mohsan Raza Shah
- Department of Botany, Division of Science and Technology, University of Education, Lahore, Pakistan
| | - Muhammad Ashraf
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
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Mehltreter K, Wachter H, Trabi C, Testo W, Sundue M, Jansen S. Hydathodes in ferns: their phylogenetic distribution, structure and function. Ann Bot 2022; 130:331-344. [PMID: 35696156 PMCID: PMC9486916 DOI: 10.1093/aob/mcac076] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Ferns are the second largest group of vascular plants and are distributed nearly worldwide. Although ferns have been integrated into some comparative ecological studies focusing on hydathodes, there is a considerable gap in our understanding of the functional anatomy of these secretory tissues that are found on the vein endings of many fern leaves. In this study, we aimed to investigate the phylogenetic distribution, structure and function of fern hydathodes. METHODS We performed a global review on fern hydathodes and their phylogenetic distribution, carried out an ancestral character state reconstruction, and studied the structure, guttation and elemental composition of salt residues of eight species, and the diurnal patterns of xylem pressure of two species. KEY RESULTS Hydathodes are known from 1189 fern species, 92 genera and 19 families of 2 orders, Equisetales and Polypodiales. Stochastic character mapping indicated multiple gains and losses of hydathodes at the genus level, occurring especially during the last 50 million years of fern evolution. Hydathodes were located on the adaxial leaf surface and characterized by a cytoplasm-rich, pore-free epidermis, and became functional for several weeks after nearly complete leaf expansion. In two species, positive xylem pressure built up at night, potentially facilitating guttation. Guttation fluid was rich in Ca and often Si, but also contained P, Mg, Na and Al. CONCLUSIONS Stochastic character mapping and the structural and functional diversity of hydathodes indicate multiple origins, and their presence/absence in closely related taxa implies secondary losses during fern evolution. Positive xylem pressure and high air humidity play an important role as drivers of guttation. Hydathodes may contribute to the regulation of leaf nutrient stoichiometry by the release of excessive compounds and minerals other than waste products, but the presence of essential chemical elements in salt residues also indicates possible leakage.
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Affiliation(s)
| | - Hanna Wachter
- Institute of Systematic Botany and Ecology, Ulm University, D-89081 Ulm, Germany
| | - Christophe Trabi
- Institute of Systematic Botany and Ecology, Ulm University, D-89081 Ulm, Germany
| | - Weston Testo
- Department of Biological and Environmental Sciences, University of Gothenburg, 40530 Goteborg, Sweden
- Botanical Research Institute of Texas, Fort Worth, TX 76107, USA
| | - Michael Sundue
- The Pringle Herbarium, Department of Plant Biology, University of Vermont, Burlington, VT 05405, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, D-89081 Ulm, Germany
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Mir R, Romero I, González-Orenga S, Ferrer-Gallego PP, Laguna E, Boscaiu M, Oprică L, Grigore MN, Vicente O. Constitutive and Adaptive Traits of Environmental Stress Tolerance in the Threatened Halophyte Limonium angustebracteatum Erben (Plumbaginaceae). Plants (Basel) 2022; 11:plants11091137. [PMID: 35567138 PMCID: PMC9103948 DOI: 10.3390/plants11091137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/20/2022] [Accepted: 04/20/2022] [Indexed: 06/01/2023]
Abstract
Limonium angustebracteatum is a halophyte endemic to the E and SE Iberian Peninsula with interest in conservation. Salt glands represent an important adaptive trait in recretohalophytes like this and other Limonium species, as they allow the excretion of excess salts, reducing the concentration of toxic ions in foliar tissues. This study included the analysis of the salt gland structure, composed of 12 cells, 4 secretory and 8 accessory. Several anatomical, physiological and biochemical responses to stress were also analysed in adult plants subjected to one month of water stress, complete lack of irrigation, and salt stress, by watering with aqueous solutions of 200, 400, 600 and 800 mM NaCl. Plant growth was inhibited by the severe water deficit and, to a lesser extent, by high NaCl concentrations. A variation in the anatomical structure of the leaves was detected under conditions of salt and water stress; plants from the salt stress treatment showed salt glands sunken between epidermal cells, bordered by very large epidermal cells, whereas in those from the water stress treatment, the epidermal cells were heterogeneous in shape and size. In both, the palisade structure of the leaves was altered. Salt excretion is usually accompanied by the accumulation of salts in the foliar tissue. This was also found in L. angustebracteatum, in which the concentration of all ions analysed was higher in the leaves than in the roots. The increase of K+ in the roots of plants subjected to water stress was also remarkable. The multivariate analysis indicated differences in water and salt stress responses, such as the accumulation of Na and Cl, or proline, but K+ homeostasis played a relevant role in the mechanism of tolerance to both stressful conditions.
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Affiliation(s)
- Ricardo Mir
- Institute for the Conservation and Improvement of Valencian Agrodiversity (COMAV, UPV), Universitat Politècnica de València, Camino de Vera 14, 46022 Valencia, Spain; (R.M.); (I.R.); (O.V.)
| | - Ignacio Romero
- Institute for the Conservation and Improvement of Valencian Agrodiversity (COMAV, UPV), Universitat Politècnica de València, Camino de Vera 14, 46022 Valencia, Spain; (R.M.); (I.R.); (O.V.)
| | - Sara González-Orenga
- Mediterranean Agroforestry Institute (IAM, UPV), Universitat Politècnica de València, Camino de Vera 14, 46022 Valencia, Spain; (S.G.-O.); (M.B.)
| | - P. Pablo Ferrer-Gallego
- Centre for Forestry Research and Experimentation (CIEF), CIEF-Wildlife Service, Generalitat Valenciana, Avda Comarques del País Valencia, 114, 46930 Quart de Poblet, Valencia, Spain; (P.P.F.-G.); (E.L.)
| | - Emilio Laguna
- Centre for Forestry Research and Experimentation (CIEF), CIEF-Wildlife Service, Generalitat Valenciana, Avda Comarques del País Valencia, 114, 46930 Quart de Poblet, Valencia, Spain; (P.P.F.-G.); (E.L.)
| | - Monica Boscaiu
- Mediterranean Agroforestry Institute (IAM, UPV), Universitat Politècnica de València, Camino de Vera 14, 46022 Valencia, Spain; (S.G.-O.); (M.B.)
| | - Lăcrămioara Oprică
- Faculty of Biology, Alexandru Ioan Cuza University of Iasi, Bulevardul Carol I nr. 11, 700506 Iași, Romania;
| | - Marius-Nicușor Grigore
- Faculty of Medicine and Biological Sciences, “Ștefan cel Mare” University of Suceava, Str. Universității 13, 720229 Suceava, Romania
| | - Oscar Vicente
- Institute for the Conservation and Improvement of Valencian Agrodiversity (COMAV, UPV), Universitat Politècnica de València, Camino de Vera 14, 46022 Valencia, Spain; (R.M.); (I.R.); (O.V.)
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Caperta AD, Róis AS, Teixeira G, Garcia-Caparros P, Flowers TJ. Secretory structures in plants: Lessons from the Plumbaginaceae on their origin, evolution and roles in stress tolerance. Plant Cell Environ 2020; 43:2912-2931. [PMID: 32542760 DOI: 10.1111/pce.13825] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/21/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
The Plumbaginaceae (non-core Caryophyllales) is a family well known for species adapted to a wide range of arid and saline habitats. Of its salt-tolerant species, at least 45 are in the genus Limonium; two in each of Aegialitis, Limoniastrum and Myriolimon, and one each in Psylliostachys, Armeria, Ceratostigma, Goniolimon and Plumbago. All the halophytic members of the family have salt glands and salt glands are also common in the closely related Tamaricaceae and Frankeniaceae. The halophytic species of the three families can secrete a range of ions (Na+ , K+ , Ca2+ , Mg2+ , Cl- , HCO3- , SO42- ) and other elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Salt glands are, however, absent in salt-tolerant members of the sister family Polygonaceae. We describe the structure of the salt glands in the three families and consider whether glands might have arisen as a means to avoid the toxicity of Na+ and/or Cl- or to regulate Ca2+ concentrations with the leaves. We conclude that the establishment of lineages with salt glands took place after the split between the Polygonaceae and its sister group the Plumbaginaceae.
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Affiliation(s)
- Ana D Caperta
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa, Lisboa, Portugal
| | - Ana S Róis
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa, Lisboa, Portugal
- School of Psychology and Life Sciences, Universidade Lusófona de Humanidades e Tecnologias (ULHT), Lisboa, Portugal
| | - Generosa Teixeira
- Centre for Ecology, Evolution and Environmental Changes (CE3C), Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
- Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal
| | - Pedro Garcia-Caparros
- Agronomy Department of Superior School Engineering, University of Almeria, CIAIMBITAL, Agrifood Campus of International Excellence ceiA3, Almería, Spain
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Wei X, Yan X, Yang Z, Han G, Wang L, Yuan F, Wang B. Salt glands of recretohalophyte Tamarix under salinity: Their evolution and adaptation. Ecol Evol 2020; 10:9384-9395. [PMID: 32953068 PMCID: PMC7487237 DOI: 10.1002/ece3.6625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 11/26/2022] Open
Abstract
Here, we studied the evolution of salt glands in 11 species of Tamarix and determined their role in adaptation to saline environments by measuring the effect of NaCl on plant growth and salt gland characteristics. Cluster analysis divided Tamarix species into three types (types I-III) according to salt-gland characteristics. A phylogenetic tree based on ITS sequences indicated an evolutionary relationship consistent with the geographical distribution of Tamarix. We measured growth under different NaCl conditions (0, 100, 200, and 300 mM) for 40 days in three species (T. gallica, T. ramosissima, and T. laxa) representing the three Tamarix types. With increasing NaCl concentration, the biomass of all species was significantly reduced, especially that of T. gallica. Salt secretion ability and salt-gland density showed similar trends in three types. The order of salt tolerance was type I > type II > type III. We conclude that during Tamarix adaptation to salinity, salt-gland evolution followed two directions: one increasing salt-gland density, and the other increasing salt secretion rate per salt-gland. This study provides a basis for potential mechanisms of recretohalophyte adaptation to salinity.
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Affiliation(s)
- Xiaocen Wei
- Shandong Provincial Key Laboratory of Plant StressCollege of Life SciencesShandong Normal UniversityJi'nanChina
| | - Xin Yan
- Shandong Provincial Key Laboratory of Plant StressCollege of Life SciencesShandong Normal UniversityJi'nanChina
| | - Zhen Yang
- Shandong Provincial Key Laboratory of Microbial EngineeringSchool of Biologic EngineeringQilu University of Technology (Shandong Academy of Sciences)Ji'nanChina
| | - Guoliang Han
- Shandong Provincial Key Laboratory of Plant StressCollege of Life SciencesShandong Normal UniversityJi'nanChina
| | - Lei Wang
- Shandong Provincial Key Laboratory of Plant StressCollege of Life SciencesShandong Normal UniversityJi'nanChina
| | - Fang Yuan
- Shandong Provincial Key Laboratory of Plant StressCollege of Life SciencesShandong Normal UniversityJi'nanChina
| | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant StressCollege of Life SciencesShandong Normal UniversityJi'nanChina
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Litalien AAS, Rutter A, Zeeb BA. The impact of soil chloride concentration and salt type on the excretions of four recretohalophytes with different excretion mechanisms. Int J Phytoremediation 2020; 22:1122-1128. [PMID: 32151140 DOI: 10.1080/15226514.2020.1733485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Four natives Canadian recretohalophytic species: Atriplex canescens, Armeria maritima, Spartina pectinata, and Distichlis spicata were examined to determine their relative uptake and excretion of chloride in the context of phytoremediation. Adult plants were grown in soils contaminated with either sodium chloride or potassium chloride at various concentrations, then manually washed to collect the excreted salts. Atriplex canescens which has salt bladders, was found to have negligible excretions, suggesting that these structures release minimal amounts of salt onto the leaf's surface. Chloride excretions of S. pectinata and D. spicata increased with higher soil chloride concentrations. A. maritima showed minimal excretion until a threshold soil salinity was reached. This species shifted from a reliance on internal sequestration to secretion at higher soil salinity. The salt used in the media did not impact these trends, but D. spicata excreted significantly more chloride under sodium chloride conditions. While all four species studied were able to translocate significant amount of salt to their shoots, only S. pectinata, D. spicata, and A. maritima are suitable candidates for remediation by haloconduction. Among these, A. maritima showed the greatest potential and significantly reduced the soil chloride concentration by up to 60% in the highest concentration treatment (4 mg/g).HIGHLIGHTSArmeria maritima, Spartina pectinata, and Distichlis spicata are suitable species for remediation via haloconduction.Armeria maritima had the highest total extraction capacity at high soil chloride.Spartina pectinata had the most consistent excretion capacity and is the most suitable for remediation of soils with lower soil chloride.
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Affiliation(s)
- Amélie A S Litalien
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON, Canada
| | - Allison Rutter
- Analytical Services Unit, Queen's University, Kingston, ON, Canada
| | - Barbara A Zeeb
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON, Canada
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Cavé-Radet A, Rabhi M, Gouttefangeas F, El Amrani A. Do Specialized Cells Play a Major Role in Organic Xenobiotic Detoxification in Higher Plants? Front Plant Sci 2020; 11:1037. [PMID: 32733524 PMCID: PMC7363956 DOI: 10.3389/fpls.2020.01037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 06/24/2020] [Indexed: 05/18/2023]
Abstract
In the present work, we used a double cell screening approach based on phenanthrene (phe) epifluorescence histochemical localization and oxygen radical detection to generate new data about how some specialized cells are involved in tolerance to organic xenobiotics. Thereby, we bring new insights about phe [a common Polycyclic Aromatic Hydrocarbon (PAH)] cell specific detoxification, in two contrasting plant lineages thriving in different ecosystems. Our data suggest that in higher plants, detoxification may occur in specialized cells such as trichomes and pavement cells in Arabidopsis, and in the basal cells of salt glands in Spartina species. Such features were supported by a survey from the literature, and complementary data correlating the size of basal salt gland cells and tolerance abilities to PAHs previously reported between Spartina species. Furthermore, we conducted functional validation in two independent Arabidopsis trichomeless glabrous T-DNA mutant lines (GLABRA1 mutants). These mutants showed a sensitive phenotype under phe-induced stress in comparison with their background ecotypes without the mutation, indicating that trichomes are key structures involved in the detoxification of organic xenobiotics. Interestingly, trichomes and pavement cells are known to endoreduplicate, and we discussed the putative advantages given by endopolyploidy in xenobiotic detoxification abilities. The same feature concerning basal salt gland cells in Spartina has been raised. This similarity with detoxification in the endopolyploid liver cells of the animal system is included.
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Affiliation(s)
- Armand Cavé-Radet
- Université de Rennes 1, CNRS/OSUR-UMR 6553, Ecosystèmes-Biodiversité-Evolution, Rennes, France
- *Correspondence: Armand Cavé-Radet, ; Mokded Rabhi, ; Abdelhak El Amrani,
| | - Mokded Rabhi
- Department of Plant Production and Protection, College of Agriculture and Veterinary Medicine, Qassim University, Qassim, Saudi Arabia
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
- *Correspondence: Armand Cavé-Radet, ; Mokded Rabhi, ; Abdelhak El Amrani,
| | - Francis Gouttefangeas
- Université de Rennes 1, ScanMAT - Synthèse, Caractérisation et ANalyse de la MATière, Rennes, France
| | - Abdelhak El Amrani
- Université de Rennes 1, CNRS/OSUR-UMR 6553, Ecosystèmes-Biodiversité-Evolution, Rennes, France
- *Correspondence: Armand Cavé-Radet, ; Mokded Rabhi, ; Abdelhak El Amrani,
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Newete SW, Allem SM, Venter N, Byrne MJ. Tamarix efficiency in salt excretion and physiological tolerance to salt-induced stress in South Africa. Int J Phytoremediation 2019; 22:3-9. [PMID: 31271050 DOI: 10.1080/15226514.2019.1633997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This study, investigated the salt excretion efficiency and the level of the physiological response to salt-induced stresses between the native and exotic Tamarix species as well as their hybrids (Tamarix chinensis × Tamarix ramosissima and Tamarix chinensis × Tamarix usneoides). Ten potted plants from each of the five taxa were exposed to salt at a concentration of 3% (w/w) (180 mM) for 3 weeks. Measurements of electro-conductivity (EC), physiological parameters such as stomatal conductance, chlorophyll fluorescence, and water pressure and plant growth were taken from salt-treated and control plants. The EC in the exotic T. chinensis significantly increased by >30% compared with all other Tamarix taxa, suggesting that it is the most effective taxon for phytoremediation. Although there was no significant difference in plant growth between T. chinensis and T. usneoides, they both showed a significantly greater plant growth than the other taxa. However, the plant physiological parameters indicated that T. usneoides was less stressed by the salt exposure than the T. chinensis and the others. Thus, considering the T. usneoides greater tolerance to salt-induced and/water stresses and the strict environmental regulations of planting exotic Tamarix, the native Tamarix remains the preferred plant of choice for phytoremediation in South Africa.
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Affiliation(s)
- Solomon Wakshom Newete
- Geoinformation Science Devision, Agricultural Research Council - Institute for Soil, Climate and Water (ARC-ISCW), Pretoria, South Africa
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Stawm Megan Allem
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nic Venter
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Marcus John Byrne
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
- DST-NRF Centre of Excellence for Invasion Biology, Johannesburg, South Africa
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Al Hassan M, Estrelles E, Soriano P, López-Gresa MP, Bellés JM, Boscaiu M, Vicente O. Unraveling Salt Tolerance Mechanisms in Halophytes: A Comparative Study on Four Mediterranean Limonium Species with Different Geographic Distribution Patterns. Front Plant Sci 2017; 8:1438. [PMID: 28861106 PMCID: PMC5562691 DOI: 10.3389/fpls.2017.01438] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/03/2017] [Indexed: 05/23/2023]
Abstract
We have performed an extensive study on the responses to salt stress in four related Limonium halophytes with different geographic distribution patterns, during seed germination and early vegetative growth. The aims of the work were twofold: to establish the basis for the different chorology of these species, and to identify relevant mechanisms of salt tolerance dependent on the control of ion transport and osmolyte accumulation. Seeds were germinated in vitro, in the presence of increasing NaCl concentrations, and subjected to "recovery of germination" tests; germination percentages and velocity were determined to establish the relative tolerance and competitiveness of the four Limonium taxa. Salt treatments were also applied to young plants, by 1-month irrigation with NaCl up to 800 mM; then, growth parameters, levels of monovalent and divalent ions (in roots and leaves), and leaf contents of photosynthetic pigments and common osmolytes were determined in control and stressed plants of the four species. Seed germination is the most salt-sensitive developmental phase in Limonium. The different germination behavior of the investigated species appears to be responsible for their geographical range size: L. narbonense and L. virgatum, widespread throughout the Mediterranean, are the most tolerant and the most competitive at higher soil salinities; the endemic L. santapolense and L. girardianum are the most sensitive and more competitive only at lower salinities. During early vegetative growth, all taxa showed a strong tolerance to salt stress, although slightly higher in L. virgatum and L. santapolense. Salt tolerance is based on the efficient transport of Na+ and Cl- to the leaves and on the accumulation of fructose and proline for osmotic adjustment. Despite some species-specific quantitative differences, the accumulation patterns of the different ions were similar in all species, not explaining differences in tolerance, except for the apparent activation of K+ transport to the leaves at high external salinity, observed only in the most tolerant L. narbonense and L. virgatum. This specific response may be therefore relevant for salt tolerance in Limonium. The ecological implications of these results, which can contribute to a more efficient management of salt marshes conservation/regeneration programs, are also discussed.
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Affiliation(s)
- Mohamad Al Hassan
- Instituto de Biología Molecular y Celular de Plantas, (UPV-CSIC), Universitat Politècnica de ValènciaValencia, Spain
| | - Elena Estrelles
- Jardín Botánico—ICBiBE, Universitat de ValènciaValencia, Spain
| | - Pilar Soriano
- Jardín Botánico—ICBiBE, Universitat de ValènciaValencia, Spain
| | - María P. López-Gresa
- Instituto de Biología Molecular y Celular de Plantas, (UPV-CSIC), Universitat Politècnica de ValènciaValencia, Spain
| | - José M. Bellés
- Instituto de Biología Molecular y Celular de Plantas, (UPV-CSIC), Universitat Politècnica de ValènciaValencia, Spain
| | - Monica Boscaiu
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de ValènciaValencia, Spain
| | - Oscar Vicente
- Instituto de Biología Molecular y Celular de Plantas, (UPV-CSIC), Universitat Politècnica de ValènciaValencia, Spain
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Dassanayake M, Larkin JC. Corrigendum: Making Plants Break a Sweat: the Structure, Function, and Evolution of Plant Salt Glands. Front Plant Sci 2017; 8:724. [PMID: 28491080 PMCID: PMC5420577 DOI: 10.3389/fpls.2017.00724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 04/19/2017] [Indexed: 05/25/2023]
Abstract
[This corrects the article on p. 406 in vol. 8, PMID: 28400779.].
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Dassanayake M, Larkin JC. Making Plants Break a Sweat: the Structure, Function, and Evolution of Plant Salt Glands. Front Plant Sci 2017; 8:406. [PMID: 28400779 PMCID: PMC5368257 DOI: 10.3389/fpls.2017.00406] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/09/2017] [Indexed: 05/25/2023]
Abstract
Salt stress is a complex trait that poses a grand challenge in developing new crops better adapted to saline environments. Some plants, called recretohalophytes, that have naturally evolved to secrete excess salts through salt glands, offer an underexplored genetic resource for examining how plant development, anatomy, and physiology integrate to prevent excess salt from building up to toxic levels in plant tissue. In this review we examine the structure and evolution of salt glands, salt gland-specific gene expression, and the possibility that all salt glands have originated via evolutionary modifications of trichomes. Salt secretion via salt glands is found in more than 50 species in 14 angiosperm families distributed in caryophyllales, asterids, rosids, and grasses. The salt glands of these distantly related clades can be grouped into four structural classes. Although salt glands appear to have originated independently at least 12 times, they share convergently evolved features that facilitate salt compartmentalization and excretion. We review the structural diversity and evolution of salt glands, major transporters and proteins associated with salt transport and secretion in halophytes, salt gland relevant gene expression regulation, and the prospect for using new genomic and transcriptomic tools in combination with information from model organisms to better understand how salt glands contribute to salt tolerance. Finally, we consider the prospects for using this knowledge to engineer salt glands to increase salt tolerance in model species, and ultimately in crops.
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Affiliation(s)
- Maheshi Dassanayake
- Department of Biological Sciences, Louisiana State University, Baton RougeLA, USA
| | - John C. Larkin
- Department of Biological Sciences, Louisiana State University, Baton RougeLA, USA
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Volkov V, Beilby MJ. Editorial: Salinity Tolerance in Plants: Mechanisms and Regulation of Ion Transport. Front Plant Sci 2017; 8:1795. [PMID: 29114255 PMCID: PMC5660868 DOI: 10.3389/fpls.2017.01795] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/03/2017] [Indexed: 05/17/2023]
Affiliation(s)
- Vadim Volkov
- Faculty of Life Sciences and Computing, London Metropolitan University, London, United Kingdom
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, CA, United States
- *Correspondence: Vadim Volkov
| | - Mary J. Beilby
- School of Physics, University of New South Wales, Sydney, NSW, Australia
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Krishnamurthy P, Jyothi-Prakash PA, Qin L, He J, Lin Q, Loh CS, Kumar PP. Role of root hydrophobic barriers in salt exclusion of a mangrove plant Avicennia officinalis. Plant Cell Environ 2014; 37:1656-71. [PMID: 24417377 DOI: 10.1111/pce.12272] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/17/2013] [Accepted: 01/04/2014] [Indexed: 05/17/2023]
Abstract
Salt exclusion at the roots and salt secretion in the leaves were examined in a mangrove, Avicennia officinalis. The non-secretor mangrove Bruguiera cylindrica was used for comparative 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 were found in the roots of B. cylindrica even in the absence of 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 endodermis is the primary site of salt exclusion. Enhanced salt secretion and increased suberin deposition surrounding the salt glands were seen in the leaves with salt treatment. 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.
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Affiliation(s)
- Pannaga Krishnamurthy
- Department of Biological Sciences, National University of Singapore, 117543, Singapore; NUS Environmental Research Institute (NERI), National University of Singapore, 117411, Singapore
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Tan WK, Lin Q, Lim TM, Kumar P, Loh CS. Dynamic secretion changes in the salt glands of the mangrove tree species Avicennia officinalis in response to a changing saline environment. Plant Cell Environ 2013; 36:1410-22. [PMID: 23336288 DOI: 10.1111/pce.12068] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 01/07/2013] [Indexed: 05/22/2023]
Abstract
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.
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Affiliation(s)
- Wee-Kee Tan
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543.
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