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Li S, Lu S, Wang J, Liu Z, Yuan C, Wang M, Guo J. Divergent effects of single and combined stress of drought and salinity on the physiological traits and soil properties of Platycladus orientalis saplings. FRONTIERS IN PLANT SCIENCE 2024; 15:1351438. [PMID: 38903426 PMCID: PMC11187290 DOI: 10.3389/fpls.2024.1351438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 05/22/2024] [Indexed: 06/22/2024]
Abstract
Drought and salinity are two abiotic stresses that affect plant productivity. We exposed 2-year-old Platycladus orientalis saplings to single and combined stress of drought and salinity. Subsequently, the responses of physiological traits and soil properties were investigated. Biochemical traits such as leaf and root phytohormone content significantly increased under most stress conditions. Single drought stress resulted in significantly decreased nonstructural carbohydrate (NSC) content in stems and roots, while single salt stress and combined stress resulted in diverse response of NSC content. Xylem water potential of P. orientalis decreased significantly under both single drought and single salt stress, as well as the combined stress. Under the combined stress of drought and severe salt, xylem hydraulic conductivity significantly decreased while NSC content was unaffected, demonstrating that the risk of xylem hydraulic failure may be greater than carbon starvation. The tracheid lumen diameter and the tracheid double wall thickness of root and stem xylem was hardly affected by any stress, except for the stem tracheid lumen diameter, which was significantly increased under the combined stress. Soil ammonium nitrogen, nitrate nitrogen and available potassium content was only significantly affected by single salt stress, while soil available phosphorus content was not affected by any stress. Single drought stress had a stronger effect on the alpha diversity of rhizobacteria communities, and single salt stress had a stronger effect on soil nutrient availability, while combined stress showed relatively limited effect on these soil properties. Regarding physiological traits, responses of P. orientalis saplings under single and combined stress of drought and salt were diverse, and effects of combined stress could not be directly extrapolated from any single stress. Compared to single stress, the effect of combined stress on phytohormone content and hydraulic traits was negative to P. orientalis saplings, while the combined stress offset the negative effects of single drought stress on NSC content. Our study provided more comprehensive information on the response of the physiological traits and soil properties of P. orientalis saplings under single and combined stress of drought and salt, which would be helpful to understand the adapting mechanism of woody plants to abiotic stress.
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Affiliation(s)
- Shan Li
- Department of Environmental Science and Ecology, School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi’an, China
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Li N, Shao T, Xu L, Long X, Rengel Z, Zhang Y. Transcriptome analysis reveals the molecular mechanisms underlying the enhancement of salt-tolerance in Melia azedarach under salinity stress. Sci Rep 2024; 14:10981. [PMID: 38745099 PMCID: PMC11094156 DOI: 10.1038/s41598-024-61907-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/10/2024] [Indexed: 05/16/2024] Open
Abstract
Melia azedarach demonstrates strong salt tolerance and thrives in harsh saline soil conditions, but the underlying mechanisms are poorly understood. In this study, we analyzed gene expression under low, medium, and high salinity conditions to gain a deeper understanding of adaptation mechanisms of M. azedarach under salt stress. The GO (gene ontology) analysis unveiled a prominent trend: as salt stress intensified, a greater number of differentially expressed genes (DEGs) became enriched in categories related to metabolic processes, catalytic activities, and membrane components. Through the analysis of the category GO:0009651 (response to salt stress), we identified four key candidate genes (CBL7, SAPK10, EDL3, and AKT1) that play a pivotal role in salt stress responses. Furthermore, the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis revealed that DEGs were significantly enriched in the plant hormone signaling pathways and starch and sucrose metabolism under both medium and high salt exposure in comparison to low salt conditions. Notably, genes involved in JAZ and MYC2 in the jasmonic acid (JA) metabolic pathway were markedly upregulated in response to high salt stress. This study offers valuable insights into the molecular mechanisms underlying M. azedarach salt tolerance and identifies potential candidate genes for enhancing salt tolerance in M. azedarach.
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Affiliation(s)
- Na Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Tianyun Shao
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Li Xu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiaohua Long
- Institute of Crop sciences, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Inner Mongolia, 010031, China.
| | - Zed Rengel
- Soil Science and Plant Nutrition, UWA School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- Institute for Adriatic Crops and Karst Reclamation, 21000, Split, Croatia
| | - Yu Zhang
- Institute of Crop sciences, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Inner Mongolia, 010031, China
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Caplan JS, Salisbury AB, McKenzie ER, Behbahani A, Eisenman SW. Spatial, temporal, and biological factors influencing plant responses to deicing salt in roadside bioinfiltration basins. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 359:120761. [PMID: 38703641 DOI: 10.1016/j.jenvman.2024.120761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 03/13/2024] [Accepted: 03/23/2024] [Indexed: 05/06/2024]
Abstract
Plants are arguably the most visible components of stormwater bioretention basins and play key roles in stabilizing soils and removing water through transpiration. In regions with cold winters, bioretention basins along roadways can receive considerable quantities of deicing salt, much of which migrates out of the systems prior to the onset of plant growth but the rest remains in the soil. The resulting effects on plants presumably vary with time (due to annual weather patterns), space (because stormwater exposure is location-dependent), and biology (because plant taxa differ in their salt tolerance). The goal of this study was to investigate the magnitude of deicing salt's effects on bioretention plants and how it varies with spatial, temporal, and biological factors. The study took place in a set of five bioretention basins in Philadelphia, USA that receive runoff from a major highway. Over a five-year period, the electrical conductivity (EC) of influent stormwater frequently exceeded 1 mS cm-1 in winter, and occasionally surpassed that of seawater (∼50 mS cm-1). In both of the years when soil EC was measured as well, it remained elevated through all spring months, especially near basin inlets and centers. Mortality of nine plant taxa ranged widely after three years (0-90%), with rankings largely corresponding to salt tolerances. Moreover, leaf areas and/or crown volumes were strongly reduced in proportion to stormwater exposure in seven of these taxa. In the three taxa evaluated for tissue concentrations of 14 potentially toxic elements (Hemerocallis 'Happy Returns', Iris 'Caesar's Brother', and Cornus sericea 'Cardinal'), only sodium consistently exceeded the toxicity limit for salt intolerant plants (500 mg kg-1). However, exceedance of the sodium toxicity limit was associated with plants' topographic positions, with median concentrations greatest in the bottom of basins and least on basin rims. This study demonstrates that deicing salts can have detrimental effects on plants in bioretention basins, with the strongest effects likely to occur in years with the greatest snowfall (and therefore deicing salt use), in portions of basins with greatest stormwater exposure (typically around inlets and centers), and in plants with minimal salinity tolerance. Our results therefore underscore the value of installing salt-tolerant taxa in basins likely to experience any frequency of deicing salt exposure.
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Affiliation(s)
- Joshua S Caplan
- Department of Architecture & Environmental Design, Temple University, 580 Meetinghouse Road, Ambler 19002, PA, USA.
| | - Allyson B Salisbury
- Department of Architecture & Environmental Design, Temple University, 580 Meetinghouse Road, Ambler 19002, PA, USA.
| | - Erica R McKenzie
- Department of Civil & Environmental Engineering, Temple University, 1947 N. 12th Street, Philadelphia 19122, PA, USA.
| | - Ali Behbahani
- Department of Civil & Environmental Engineering, Temple University, 1947 N. 12th Street, Philadelphia 19122, PA, USA.
| | - Sasha W Eisenman
- Department of Architecture & Environmental Design, Temple University, 580 Meetinghouse Road, Ambler 19002, PA, USA.
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Beckett HAA, Bryant C, Neeman T, Mencuccini M, Ball MC. Plasticity in branch water relations and stem hydraulic vulnerability enhances hydraulic safety in mangroves growing along a salinity gradient. PLANT, CELL & ENVIRONMENT 2024; 47:854-870. [PMID: 37975319 DOI: 10.1111/pce.14764] [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: 08/09/2023] [Revised: 10/05/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Coping with water stress depends on maintaining cellular function and hydraulic conductance. Yet measurements of vulnerability to drought and salinity do not often focus on capacitance in branch organs that buffer hydraulic function during water stress. The relationships between branch water relations, stem hydraulic vulnerability and stem anatomy were investigated in two co-occurring mangroves Aegiceras corniculatum and Rhizophora stylosa growing at low and high salinity. The dynamics of branch water release acted to conserve water content in the stem at the expense of the foliage during extended drying. Hydraulic redistribution from the foliage to the stem increased stem relative water content by up to 21%. The water potentials at which 12% and 50% loss of stem hydraulic conductivity occurred decreased by ~1.7 MPa in both species between low and high salinity sites. These coordinated tissue adjustments increased hydraulic safety despite declining turgor safety margins at higher salinity sites. Our results highlight the complex interplay of plasticity in organ-level water relations with hydraulic vulnerability in the maintenance of stem hydraulic function in mangroves distributed along salinity gradients. These results emphasise the importance of combining water relations and hydraulic vulnerability parameters to understand vulnerability to water stress across the whole plant.
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Affiliation(s)
- Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Callum Bryant
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Teresa Neeman
- Biological Data Science Institute, Australian National University, Canberra, Australia
| | - Maurizio Mencuccini
- Ecological and Forestry Applications Research Centre (CREAF), Barcelona, Bellaterra, Spain
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
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Abstract
Marine transgression associated with rising sea levels causes coastal erosion, landscape transitions, and displacement of human populations globally. This process takes two general forms. Along open-ocean coasts, active transgression occurs when sediment-delivery rates are unable to keep pace with accommodation creation, leading to wave-driven erosion and/or landward translation of coastal landforms. It is highly visible, rapid, and limited to narrow portions of the coast. In contrast, passive transgression is subtler and slower, and impacts broader areas. It occurs along low-energy, inland marine margins; follows existing upland contours; and is characterized predominantly by the landward translation of coastal ecosystems. The nature and relative rates of transgression along these competing margins lead to expansion and/or contraction of the coastal zone and-particularly under the influence of anthropogenic interventions-will dictate future coastal-ecosystem response to sea-level rise, as well as attendant, often inequitable, impacts on human populations.
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Affiliation(s)
- Christopher J Hein
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, USA; ,
| | - Matthew L Kirwan
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, USA; ,
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Chen Y, Kirwan ML. Upland forest retreat lags behind sea-level rise in the mid-Atlantic coast. GLOBAL CHANGE BIOLOGY 2024; 30:e17081. [PMID: 38273570 DOI: 10.1111/gcb.17081] [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: 08/25/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 01/27/2024]
Abstract
Ghost forests consisting of dead trees adjacent to marshes are striking indicators of climate change, and marsh migration into retreating coastal forests is a primary mechanism for marsh survival in the face of global sea-level rise. Models of coastal transgression typically assume inundation of a static topography and instantaneous conversion of forest to marsh with rising seas. In contrast, here we use four decades of satellite observations to show that many low-elevation forests along the US mid-Atlantic coast have survived despite undergoing relative sea-level rise rates (RSLRR) that are among the fastest on Earth. Lateral forest retreat rates were strongly mediated by topography and seawater salinity, but not directly explained by spatial variability in RSLRR, climate, or disturbance. The elevation of coastal tree lines shifted upslope at rates correlated with, but far less than, contemporary RSLRR. Together, these findings suggest a multi-decadal lag between RSLRR and land conversion that implies coastal ecosystem resistance. Predictions based on instantaneous conversion of uplands to wetlands may therefore overestimate future land conversion in ways that challenge the timing of greenhouse gas fluxes and marsh creation, but also imply that the full effects of historical sea-level rise have yet to be realized.
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Affiliation(s)
- Yaping Chen
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, USA
| | - Matthew L Kirwan
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, USA
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Ding J, McDowell N, Fang Y, Ward N, Kirwan ML, Regier P, Megonigal P, Zhang P, Zhang H, Wang W, Li W, Pennington SC, Wilson SJ, Stearns A, Bailey V. Modeling the mechanisms of conifer mortality under seawater exposure. THE NEW PHYTOLOGIST 2023. [PMID: 37376720 DOI: 10.1111/nph.19076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023]
Abstract
Relative sea level rise (SLR) increasingly impacts coastal ecosystems through the formation of ghost forests. To predict the future of coastal ecosystems under SLR and changing climate, it is important to understand the physiological mechanisms underlying coastal tree mortality and to integrate this knowledge into dynamic vegetation models. We incorporate the physiological effect of salinity and hypoxia in a dynamic vegetation model in the Earth system land model, and used the model to investigate the mechanisms of mortality of conifer forests on the west and east coast sites of USA, where trees experience different form of sea water exposure. Simulations suggest similar physiological mechanisms can result in different mortality patterns. At the east coast site that experienced severe increases in seawater exposure, trees loose photosynthetic capacity and roots rapidly, and both storage carbon and hydraulic conductance decrease significantly within a year. Over time, further consumption of storage carbon that leads to carbon starvation dominates mortality. At the west coast site that gradually exposed to seawater through SLR, hydraulic failure dominates mortality because root loss impacts on conductance are greater than the degree of storage carbon depletion. Measurements and modeling focused on understanding the physiological mechanisms of mortality is critical to reducing predictive uncertainty.
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Affiliation(s)
- Junyan Ding
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
| | - Nate McDowell
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, USA
| | - Yilin Fang
- Earth Systems Science Division, Pacific Northwest National Lab, Richland, WA, 99352, USA
| | - Nicholas Ward
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, WA, 98382, USA
| | - Matthew L Kirwan
- Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA, 23062, USA
| | - Peter Regier
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, WA, 98382, USA
| | - Patrick Megonigal
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Peipei Zhang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Hongxia Zhang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Weibin Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Stephanie C Pennington
- Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, MD, 20740, USA
| | | | - Alice Stearns
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Vanessa Bailey
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
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Gori A, Moura BB, Sillo F, Alderotti F, Pasquini D, Balestrini R, Ferrini F, Centritto M, Brunetti C. Unveiling resilience mechanisms of Quercus ilex seedlings to severe water stress: Changes in non-structural carbohydrates, xylem hydraulic functionality and wood anatomy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:163124. [PMID: 37001665 DOI: 10.1016/j.scitotenv.2023.163124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 05/13/2023]
Abstract
Over the last few decades, extensive dieback and mortality episodes of Quercus ilex L. have been documented after severe drought events in many Mediterranean forests. However, the underlying physiological, anatomical, and biochemical mechanisms remain poorly understood. We investigated the physiological and biochemical processes linked to embolism formation and non-structural carbohydrates (NSCs) dynamics in Q. ilex seedlings exposed to severe water stress and rewatering. Measurements of leaf gas exchange, water relations, non-structural carbohydrates, drought-related gene expression, and anatomical changes in wood parenchyma were assessed. Under water stress, the midday stem water potential dropped below - 4.5 MPa corresponding to a ~ 50 % loss of hydraulic conductivity. A 70 % reduction in stomatal conductance led to a strong depletion of wood NSCs. Starch consumption, resulting from the upregulation of the β-amylase gene BAM3, together with the downregulation of glucose (GPT1) and sucrose (SUC27) transport genes, suggests glucose utilization to sustain cellular metabolism in the wood parenchyma. After rewatering, the presence of residual xylem embolism led to an incomplete recovery of leaf gas exchanges. However, the partial restoration of photosynthesis allowed the accumulation of new starch reserves in the wood parenchyma and the production of new narrower vessels. In addition, changes in the cell wall composition of the wood parenchyma fibers were observed. Our findings indicate that thirty days of rewatering were sufficient to restore the NSCs reserves and growth rates of Q. ilex seedlings and that the carryover effects of water stress were primarily caused by hydraulic dysfunction.
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Affiliation(s)
- Antonella Gori
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy; National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy.
| | - Barbara Baesso Moura
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Fabiano Sillo
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Francesca Alderotti
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Dalila Pasquini
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Raffaella Balestrini
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Francesco Ferrini
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy; National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Mauro Centritto
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Cecilia Brunetti
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy.
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LaFond-Hudson S, Sulman B. Modeling strategies and data needs for representing coastal wetland vegetation in land surface models. THE NEW PHYTOLOGIST 2023; 238:938-951. [PMID: 36683447 DOI: 10.1111/nph.18760] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Vegetated coastal ecosystems sequester carbon rapidly relative to terrestrial ecosystems. Coastal wetlands are poorly represented in land surface models, but work is underway to improve process-based, predictive modeling of these ecosystems. Here, we identify guiding questions, potential simulations, and data needs to make progress in improving representation of vegetation in terrestrial-aquatic interfaces, with a focus on coastal and estuarine ecosystems. We synthesize relevant plant traits and environmental controls on vegetation that influence carbon cycling in coastal ecosystems. We propose that models include separate plant functional types (PFTs) for mangroves, graminoid salt marshes, and succulent salt marshes to adequately represent the variation in aboveground and belowground productivity between common coastal wetland vegetation types. We also discuss the drivers and carbon storage consequences of shifts in dominant PFTs. We suggest several potential approaches to represent the diversity in vegetation tolerance and adaptations to fluctuations in salinity and water level, which drive key gradients in coastal wetland ecosystems. Finally, we discuss data needs for parameterizing and evaluating model implementations of coastal wetland vegetation types and function.
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Affiliation(s)
- Sophia LaFond-Hudson
- Environmental Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37917, USA
| | - Benjamin Sulman
- Environmental Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37917, USA
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