Ammonium nutrition in the halophyte Spartina alterniflora under salt stress: evidence for a priming effect of ammonium?

Hessini, Kamel; Hamed, Karim Ben; Gandour, Mhemmed; Mejri, Maroua; Abdelly, Chédly; Cruz, Cristina

doi:10.1007/s11104-013-1616-1

Cited by 75 publications

(40 citation statements)

References 40 publications

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“…Early studies of S. alterniflora have clearly demonstrated that ammonium enrichment promotes higher growth over nitrate (Mendelssohn ), particularly with high salinities (Hessini et al. ).…”

Section: Discussionmentioning

confidence: 99%

Saltmarsh plant responses to eutrophication

Johnson¹,

Warren

Deegan

et al. 2016

Ecological Applications

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Abstract. In saltmarsh plant communities, bottom-up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short-term, plot-level (e.g., 1-300 m 2 ) studies, which may miss landscape-level phenomena that drive ecosystem-level responses. We implemented an ecosystem-scale, nine-year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70-100 μM NO 3 − ), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (~60,000 m 2 creeksheds). Our enrichments added a total of 1,700 kg N·creek −1 ·yr −1 , which increased N loading 10-fold vs. reference creeks (low-marsh, 171 g N·m −2 ·yr −1 ; high-marsh, 19 g N·m −2 ·yr −1 ). Nutrients increased the shoot mass and height of low marsh, tall Spartina alterniflora; however, declines in stem density resulted in no consistent increase in aboveground biomass. High-marsh plants S. patens and stunted S. alterniflora did not respond consistently to enrichment. Nutrient enrichment did not shift community structure, contrary to the prediction of nutrient-driven dominance of S. alterniflora and Distichlis spicata over S. patens. Our mild responses may differ from the results of previous studies for a number of reasons. First, the limited response of the high marsh may be explained by loading rates orders of magnitude lower than previous work. Low loading rates in the high marsh reflect infrequent inundation, arguing that inundation patterns must be considered when predicting responses to estuarine eutrophication. Additionally, we applied nitrate instead of the typically used ammonium, which is energetically favored over nitrate for plant uptake. Thus, the form of nitrogen enrichment used, not just N-load, may be important in predicting plant responses. Overall, our results suggest that when coastal eutrophication is dominated by nitrate and delivered via flooding tidal water, aboveground saltmarsh plant responses may be limited despite moderate-to-high water-column N concentrations. Furthermore, we argue that the methodological limitations of nutrient studies must be considered when using results to inform management decisions about wetlands.

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Section: Discussionmentioning

confidence: 99%

Saltmarsh plant responses to eutrophication

Johnson¹,

Warren

Deegan

et al. 2016

Ecological Applications

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“…The application of NH 4 NO 3 dramatically improved the salinity-induced growth retardation of C. roseus compared to the application of only NO 3 - (Tang et al 2011). Also, ammonium-fed S. alterniflora plants under salt stress exhibited faster growth than nitratefed plants (Hessini et al 2013). However, some studies demonstrated that nitrate-fed P. canescens plants are less sensitive to salt stress Ehlting et al 2007).…”

Section: Nhmentioning

confidence: 99%

“…For example, the retarded growth that is observed for Catharanthus roseus under salt stress could be largely ameliorated by fertilization with both ammonium and nitrate (Tang et al 2011). Ammonium-fed plants of the halophyte Spartina alterniflora exhibited better growth than nitrate-fed plants in high salinity due to high antioxidant enzyme activity in ammonium-fed plants (Hessini et al 2013). However, ammonium might also increase sensitivity to NaCl treatment in several plant species, such as Populus canescens (Ehlting et al 2007), Pisum sativum (Speer et al 1994), and Triticum aestivum (Hawkins and Lewis 1993).…”

Section: Introductionmentioning

confidence: 99%

Net NH4 + and NO3 − fluxes, and expression of NH4 + and NO3 − transporter genes in roots of Populus simonii after acclimation to moderate salinity

Zhang

Meng

et al. 2014

Trees

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Key message Net NH 4 1 flux was higher in fine roots of P. simonii after NaCl treatment compared to the NO 3 2 flux which was consistent with the expression levels of AMTs and NRTs. Abstract The characteristics of nitrogen uptake under salt stress would provide insights into the mechanisms of salt tolerance in plants. In the present study, net NH 4 ? and NO 3 -fluxes were measured using the non-invasive microtest technique, and transcript abundance of ammonium/ nitrate transporter genes (AMTs/NRTs) were determined by real time PCR in the fine roots of Populus simonii after treatment for 21 days with 75 mM NaCl. The NH 4 ? and NO 3 -fluxes showed heterogeneous spatial patterns along the root tip in nutrient solution. The maximum influx of NH 4? occurred near the root tip, while that of NO 3 -was 15 mm from the root tip. The net NO 3 -flux was inhibited by ca. 25 % with the provision of NH 4? . On average, the newly grown fine roots took up more NH 4 ? after the 75 mM NaCl treatment than did the control. Consistent with the NH 4 ? and NO 3 -influxes, most AMTs were upregulated in the salt-treated roots relative to the control, while most NRTs were down-regulated. Our study provides insights into nitrogen uptake and the AMT/NRT expression levels in the fine roots of P. simonii after acclimation to moderate salinity. This may be valuable for understanding nitrogen uptake mechanisms after adaptation to salinity.

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“…Measurements were performed between 10 and 12 am on the leaves of plants subjected to various treatments as described by Hessini et al (2013).…”

Section: Photosynthesis Measurementsmentioning

confidence: 99%

Morph-physiological responses to water deficit in parental genotypes of Medicago truncatula recombinant inbred lines

Mahfoudh¹,

Abdelly²

2016

Afr. J. Biotechnol.

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Medicago truncatula is an omni-Mediterranean species grown as an annual forage legume. In addition to its small genome size and simple genetics, M. truncatula harbors several attributes which make it an attractive model legume. In this study, we investigated morphological and photosynthetic responses to water deficit in parental genotypes of M. truncatula recombinant inbred lines. Ten parental lines were cultivated under three water regimes (100% of field capacity (FC), 50% FC and 30% FC) and were harvested at flowering time and at the end of their lifecycle. Results from ANOVA showed that variability of measured parameters was explained by the effects of line, treatment and their interaction with treatment factor recorded the highest values. Out of the 27 traits, 14 were influenced by the line x treatment interaction. High to moderate broad-sense heritability (H²) were observed for most of the traits under control treatment and drought stress. Most of the correlations between measured traits were positive under the three water regimes. The flowering time was positively correlated with aerial and root growth rate. The tolerance of lines to water deficit seems to depend, in particular, on their ability to maintain higher photosynthetic activity. In 30% FC, principal component analysis clustered lines into two groups. The Jemalong A17 line was the least affected for most phenotypic parameters. Hence, all populations of recombinant inbred lines derived from crosses between Jemalong A17 and the remaining lines were useful for the identification of the genetic determinants for tolerance to water deficit in M. truncatula.

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Ammonium nutrition in the halophyte Spartina alterniflora under salt stress: evidence for a priming effect of ammonium?

Cited by 75 publications

References 40 publications

Saltmarsh plant responses to eutrophication

Saltmarsh plant responses to eutrophication

Net NH4 + and NO3 − fluxes, and expression of NH4 + and NO3 − transporter genes in roots of Populus simonii after acclimation to moderate salinity

Morph-physiological responses to water deficit in parental genotypes of Medicago truncatula recombinant inbred lines

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