Search results for "Onium"

The stoichiometry of particulate nutrients in Lake Tanganyika — implications for nutrient limitation of phytoplankton

1999

We studied the potential nutrient limitation of phytoplankton by means of seston nutrient stoichiometry and nutrient enrichment bioassays in the epilimnion of Lake Tanganyika. In most cases, the particulate carbon to phosphorus (C:P) ratio was high and indicated moderate P deficiency, while the respective C:N ratio mainly suggested moderate N deficiency. The N:P ratios of seston indicated rather balanced N and P supply. In three two-day enrichment bioassays in April—May 1995, a combined addition of P, N and organic carbon (glucose) always increased primary production in comparison to untreated controls. Primary production also slightly increased after the addition of phosphate-P, while the …

Limonium albuferae (Plumbaginaceae), a new polyploid species from the Eastern Iberian Peninsula

2016

A new species from Limonium (Plumbaginaceae), L. albuferae sp. nov., is described from the saline-sandy soils in the saltmarshes of the Eastern Iberian Peninsula (Devesa Albufera, Valencia province, Spain). The new species is triploid (2n = 26) and is closely related to the Western Mediterranean L. girardianum from which it morphologically differs by the major robustness, and overall dimensions of leaves, inflorescences, spikes and spikelets, and by the comparative smaller size of the outer and middle bracts.

Ammonium acts systemically while nitrate exerts an additional local effect on Medicago truncatula nodules

2020

National audience; Symbiotic nitrogen fixation (SNF) has a high energetic cost for legume plants; legumes thus reduce SNF when soil N is available. The present study aimed to increase our understanding regarding the impacts of the two principal forms of available N in soils (ammonium and nitrate) on SNF. We continuously measured the SNF of Medicago truncatula under controlled conditions. This permitted nodule sampling for comparative transcriptome profiling at points connected to the nodules' reaction following ammonium or nitrate applications. The N component of both ions systemically induced a rhythmic pattern of SNF, while the activity in control plants remained constant. This rhythmic a…

Transcriptome analysis of the Populus trichocarpa–Rhizophagus irregularis Mycorrhizal Symbiosis: Regulation of Plant and Fungal Transportomes under N…

2017

Nutrient transfer is a key feature of the arbuscular mycorrhizal (AM) symbiosis. Valuable mineral nutrients are transferred from the AM fungus to the plant, increasing its fitness and productivity, and, in exchange, the AM fungus receives carbohydrates as an energy source from the plant. Here, we analyzed the transcriptome of the Populus trichocarpa-Rhizophagus irregularis symbiosis using RNA-sequencing of non-mycorrhizal or mycorrhizal fine roots, with a focus on the effect of nitrogen (N) starvation. In R. irregularis, we identified 1,015 differentially expressed genes, whereby N starvation led to a general induction of gene expression. Genes of the functional classes of cell growth, memb…

Unraveling Salt Tolerance in Halophytes: A Comparative Study on Four Mediterranean Limonium Species with Different Geographic Distribution Patterns

2017

[EN] 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 Limoni…

Typification of the linnaean name statice limonium (Plumbaginaceae)

2018

An ancestral allele of grapevine transcription factor MYB14 promotes plant defence

2016

Highlight The molecular mechanisms underlying the elevated inducibility of stilbene in pathogen-resistant Vitis sylvestris can be explained by the increased inducibility of the MYB14 promoter.

Arginase induction represses gall development during clubroot infection in Arabidopsis.

2012

Arginase induction can play a defensive role through the reduction of arginine availability for phytophageous insects. Arginase activity is also induced during gall growth caused by Plasmodiophora brassicae infection in roots of Arabidopsis thaliana; however, its possible role in this context has been unclear. We report here that the mutation of the arginase-encoding gene ARGAH2 abrogates clubroot-induced arginase activity and results in enhanced gall size in infected roots, suggesting that arginase plays a defensive role. Induction of arginase activity in infected roots was impaired in the jar1 mutant, highlighting a link between the arginase response to clubroot and jasmonate signaling. C…

Plankton community composition in relation to availability and uptake of oxidized and reduced nitrogen

2003

Centre de Recherche en Ecologie Marine et Aquaculture de L'Houmeau (CNRS-IFREMER), BP 5, 17137 L'Houmeau, France ABSTRACT: Trends in nitrogen utilization, determined with 15 N-labeled substrates, were related to blooms of distinct phytoplankton groups in the Gulf of Riga, Baltic Sea, during May, June and July 1999. The dominant phytoplankton groups included diatoms, cryptophytes, dinoflagellates, and fila- mentous cyanobacteria. As the water column became progressively more stratified over the growing season, diatoms comprised a smaller proportion of the total phytoplankton assemblage and almost disappeared by late summer. Their disappearance correlated with undetectable surface-water nitra…

Seasonal cycle of benthic denitrification and DNRA in the aphotic coastal zone, northern Baltic Sea

2020

Current knowledge on the seasonality of benthic nitrate reduction pathways in the aphotic, density stratified coastal zone of the Baltic Sea is largely based on data from muddy sediments, neglecting the potential contribution of sandy sediments. To gain a more comprehensive understanding of seasonality in this part of the Baltic Sea coast, we measured rates of benthic denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) monthly in the ice-free period of 2016 in both sandy and muddy aphotic sediments, northwestern Gulf of Finland. No anammox was observed. The seasonal cycle of denitrification in both sediment types was related to the hydrography-driven development …