Tolerance and avoidance: Two contrasting physiological responses to salt stress in mature marsh halophytes Juncus roemerianus Scheele and Spartina alterniflora Loisel

Touchette, Brant W.; Smith, Gracen A.; Rhodes, Kirsten L.; Poole, Mariana

doi:10.1016/j.jembe.2009.08.015

Cited by 65 publications

(34 citation statements)

References 41 publications

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“…The marsh system has a small topographic slope (0.4 m/km), resulting in extensive shallow water across several 10 s of km in the coastal region. Two of the dominant halophytes that reside in the marshes are black needlerush, Juncus roemerianus, a C 3 plant forming extensive monotypic halophyte stands within the middle-to-upper marshes, and smooth cordgrass, S. alterniflora, a C 4 plant populated in the marsh's low tidal regions along creek banks and around interior ponds (Touchette et al 2009). In addition, the coastal region surrounding the Snipe Creek study area is characterized by a sea floor widely covered by the two dominant seagrass species, Syringodium filiforme and Halodule wrightii, forming an abundance of mixed seagrass beds.…”

Section: Study Sitementioning

confidence: 99%

Leaching and microbial degradation of dissolved organic matter from salt marsh plants and seagrasses

et al. 2014

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Dissolved organic matter (DOM) is outwelled from highly productive salt marshes, but its sources and fates are unclear. To examine common salt marsh plants as sources of coastal DOM, two dominant salt marsh vascular plants Spartina alterniflora and Juncus roemarianus, and two major coastal seagrasses Syringodium filiforme and Halodule wrightii, were collected from a Florida salt marsh and studied using laboratory incubation experiments. We investigated the leaching dynamics of dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and chromophoric dissolved organic matter (CDOM) from these plants, in conjunction with our field investigations of the sources and outwelling of DOM from Florida salt marshes. The leaching of DOM and CDOM from the plants was a rapid process, and leaching rates were 65-288 lM/ g dry weight/day for DOC and 3.8-16 lM/g dry weight/ day for TDN from different plants in the bacteria-inhibited incubations. DOC was proportional to TDN in the leachates, but the quantity of C and N leached was dependent on the species and growth stage of the plants. At the end of the 25-day experiments, 5.4-23 % and 10-45 % of solid phase C and N were released into DOC and TDN pools, respectively. Bacteria played an important role during the leaching process. The majority of DOC and TDN leached from marsh plants and seagrasses was labile and highly biodegradable with 56-90 % of the leached DOC and 44-72 % of the leached TDN being decomposed at the end of the experiments. The fluorescence measurements of CDOM indicate that organic matter leached from marsh plants and seagrasses contained mainly protein-like DOM which was degraded rapidly by bacteria. Our study suggests that leaching of DOM from salt marsh plants and seagrasses provide not only major sources of DOC, TDN, and CDOM that affect many biogeochemical processes, but also as important food sources to microbial communities in the marsh and adjacent coastal waters.

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Section: Study Sitementioning

confidence: 99%

Leaching and microbial degradation of dissolved organic matter from salt marsh plants and seagrasses

et al. 2014

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“…In contrast, tolerance to water stress involves maintaining adequate cell turgor while minimizing metabolic disruptions. Two of the primary mechanisms that contribute to tolerance are changes in tissue elasticity (i.e., bulk elastic modulus, ε) and osmotic adjustment involving inorganic ions, carbohydrates, and organic acids (including compatible solutes) (Touchette et al 2009;Munns and Tester 2008). Field experiments corroborated the assumption that coast-ward distribution of estuarine vegetation is limited by tolerance to physiological stressors in high-salinity marshes van Wijnen et al 1999;Crain et al 2004;Naidoo and Kift 2006).…”

Section: Tic Factorsmentioning

confidence: 73%

“…In areas with limited water availability, physiological adjustments often involve avoidance and tolerance, with most plants using some combination of the two (Touchette et al 2009). Avoidance responses may include increases in stomatal and cuticular resistance, changes in leaf morphology, and/or changes in leaf orientation.…”

Section: Tic Factorsmentioning

confidence: 99%

Dynamics of zonal halophyte communities in salt marshes in the world

Lee¹,

Kim²

2018

JMIC

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Understanding of salt marsh plant zonation caused by abiotic and biotic factors is essential for successful conservation plans in the face of ongoing environmental change. The frequency of flooding is more important than elevation in predicting marsh plant zones. Tidal marsh plants are distributed across a wide gradient of soil-water salinities. Studies done to date indicate that redox potential, ionic composition of soil, moisture content of soil, latitude, topographical, and climatic factors may play some role in forming vegetation zones. Competition and facilitation are important in mediating zonation, and the importance of facilitation of plant growth increases with increasing physical stress within the abiotic range limits. A refined understanding of facilitation along stress gradients would help inform successful restoration and management of vegetation. In the salt marsh plant community, a trade-off between belowground competitive ability and the ability to tolerate physical stressors appears to drive plant growth patterns across the landscape. Understanding and predicting shifts between bare flats and vegetated marshes is of great importance, because it provides a useful scientific basis for understanding vegetation zonation. A bimodal distribution of intertidal elevations, positive feedbacks, and alternative stable states and abrupt shifts in elevation from bare flats to vegetated states are present in salt marsh ecosystems. Strategies to assess whether alternative stable states are present are now converging in fields as disparate as desertification, limnology, oceanography, ecology and climatology. Further research should therefore focus on the conditions for and the specific mechanisms behind alternative stable states in salt marsh ecosystems.

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“…Decreasing water potential (Ψ) must be established for water to fl ow through the soil-plant-atmosphere continuum. Thus, with increasing salinity plants must generate increasingly lower Ψ to allow continued water uptake (Touchette et al 2009 ). This is achieved by increasing solute concentrations within the plant (Touchette 2007 ;Flowers and Colmer 2008 ).…”

Section: Physiology Of Salinity Tolerancementioning

confidence: 99%

Salt Adaptation Mechanisms of Halophytes: Improvement of Salt Tolerance in Crop Plants

Joshi

Mangu

Bedre

et al. 2015

Elucidation of Abiotic Stress Signaling in Plants

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Soil salinity is one of the most serious environmental factors that affect crop productivity worldwide. Inevitable global climate change leading to rise in sea water level would exacerbate degradation of irrigation systems and contamination of ground water resources, which render conventional agricultural practices impossible due to the sensitivity of most crops to salinity. Breeding for development of salt-tolerant crop plants has been a major challenge due to the complexity and multigenic control of salt tolerance traits. Halophytes are capable of surviving and thriving under salt at concentrations as high as 5 g/L, by maintaining negative water potential. Physiological and molecular studies have suggested that halophytes, unlike glycophytes, have evolved mechanisms, such as ion homeostasis through ion extrusion and compartmentalization, osmotic adjustments, and antioxidant production for adaptation to salinity. Employment of integrated approaches involving different omics tools would amplify our understanding of the biology of stress response networks in the halophytes. Translation of the knowledge and resources generated from halophyte relatives of crop plants through functional genomics will lead to the development of new breeds of crops that are suitable for saline agriculture.

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Tolerance and avoidance: Two contrasting physiological responses to salt stress in mature marsh halophytes Juncus roemerianus Scheele and Spartina alterniflora Loisel

Cited by 65 publications

References 41 publications

Leaching and microbial degradation of dissolved organic matter from salt marsh plants and seagrasses

Leaching and microbial degradation of dissolved organic matter from salt marsh plants and seagrasses

Dynamics of zonal halophyte communities in salt marshes in the world

Salt Adaptation Mechanisms of Halophytes: Improvement of Salt Tolerance in Crop Plants

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