52 research outputs found
Exhibiting toxicity: sprayed strawberries and geographies of hope
ExposiciĂłn was a 2022 art exhibition that explored seasonal farm labourersâ exposure to strawberry herbicides in Huelva, Andalusia. Drawing upon a multidisciplinary collaboration of art, social geography and soil science, the following discussion contextualises ExposiciĂłn and offers reflection on the exhibition as an immersive site for figuratively re-sensing lived experiences of heavily polluted places. The exhibition provided space in which configurations of matter, affect and atmospherics might allow contemplation of environmental toxicity, while also being a means of voicing the care, solidarity and hope enacted by affected communities
A novel method to determine trimethylantimony concentrations in plant tissue
Environmental contextAntimony enters the soil mostly through mining and shooting activities and can thereafter be taken up by plants. In the soil, antimony may undergo several transformations such as biomethylation, leading to the formation of trimethylantimony. Here, we measured for the first time the uptake and translocation of trimethylantimony in a plant using a new extraction and analysis method.
AbstractAntimony (Sb) is a relevant pollutant that can be found in elevated concentrations in soils near Sb mines and at shooting ranges. In soils, Sb occurs as trivalent Sb, SbIII, pentavalent Sb, SbV, or trimethylantimony, TMSb ((CH3)3SbO), the latter being the result of microbial biomethylation. It is important to understand the transfer of Sb species from soil to plants to assess the role of Sb in the food chain. However, this research has historically been hampered by the lack of suitable extraction and analytical methods. In this study, we validated an efficient and reliable extraction technique using oxalic acid and ascorbic acid (72.6±1.3% of Sb extracted) as well as a high-pressure liquid chromatographyâinductively coupled plasma mass spectrometry (HPLC-ICP-MS) speciation analysis method to assess the uptake of TMSb in ryegrass (Lolium perenne L.), a common pasture plant, in a hydroponics experiment. Our results show that TMSb and SbIII are not converted to other species during extraction and that TMSb is taken up by ryegrass roots and translocated to the shoots. Our study also points at specific methylationâdemethylation mechanisms occurring in the plant. Moreover, an unknown Sb species was found in the shoots of TMSb-treated plants, highlighting the need for further research. These new extraction and speciation methods will enable researchers to study the soilâplant transfer of organo-Sb compounds in a reliable and consistent manner.
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Soil Contamination with Trace Metals: Quantification, Speciation, and Source Identification
Developing new analytical techniques to measure heavy stable isotope ratios or to quantify the different species of trace metals present in the environment is essential to understand, ultimately prevent, and limit trace metal pollution in the environment
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Holocene land cover change in south-western Amazonia inferred from paleoflood archives
This study provides new data on the evolution of the landscape in south-western Amazonia during the Holocene and the impact of climate change and fluvial dynamics on the region's ecosystems. South-western Amazonia is covered by an extensive seasonally flooded savannah, known as the Llanos de Moxos. Severe drought during the southern hemisphere winter, followed by months of permanent waterlogging, means that forests only grow on the most elevated parts of the landscape, mostly river and paleoriver levees and crevasse splays. Paleoclimate reconstructions from surrounding areas show that a shift to wetter conditions at around 4 kyr BP caused an increase in forest cover. However, the impact that this change in climate had on the landscape of the Llanos de Moxos is unknown. Published lacustrine archives from the area only cover the last 2 kyr. Here we present new data from the analysis of paleosols located along a 300 km transect across the central Llanos. The analyses of stable carbon isotopes, from 36 paleosols, and biogenic silica, from 29 paleosols, show that the patchwork of forests and savannahs that we see today was established after the 4 kyr BP climate change. During the dry period between 8 and 4 kyr BP, most of the central Llanos de Moxos, nowadays covered with seasonally flooded savannah, were covered by Cerrado-like savannah in the west and by forest in the east. However, results also suggest that, at both regional and local scales, vegetation cover has been influenced by changes in topography resulting from the region's river dynamics
Identification and quantification of phytochelatins in roots of rice to long-term exposure: evidence of individual role on arsenic accumulation and translocation
Six varieties of rice were exposed to low and high levels of arsenic in the same soil. Their individual responses of expressing phytochelatins have been correlated to inorganic arsenic uptake, transport, and accumulation in the rice grai
Plant secondary metabolite-dependent plant-soil feedbacks can improve crop yield in the field.
Plant secondary metabolites that are released into the rhizosphere alter biotic and abiotic soil properties, which in turn affect the performance of other plants. How this type of plant-soil feedback affects agricultural productivity and food quality in the field in the context of crop rotations is unknown. Here, we assessed the performance, yield and food quality of three winter wheat varieties growing in field plots whose soils had been conditioned by either wild type or benzoxazinoid-deficient bx1 maize mutant plants. Following maize cultivation, we detected benzoxazinoid-dependent chemical and microbial fingerprints in the soil. The benzoxazinoid fingerprint was still visible during wheat growth, but the microbial fingerprint was no longer detected. Wheat emergence, tillering, growth, and biomass increased in wild type conditioned soils compared to bx1 mutant conditioned soils. Weed cover was similar between soil conditioning treatments, but insect herbivore abundance decreased in benzoxazinoid-conditioned soils. Wheat yield was increased by over 4% without a reduction in grain quality in benzoxazinoid-conditioned soils. This improvement was directly associated with increased germination and tillering. Taken together, our experiments provide evidence that soil conditioning by plant secondary metabolite producing plants can increase yield via plant-soil feedbacks under agronomically realistic conditions. If this phenomenon holds true across different soils and environments, optimizing root exudation chemistry could be a powerful, genetically tractable strategy to enhance crop yields without additional inputs
Identification and quantification of phytochelatins in roots of rice to long-term exposure: evidence of individual role on arsenic accumulation and translocation
Rice has the predilection to take up arsenic in the form of methylated arsenic (o-As) and inorganic arsenic species (i-As). Plants defend themselves using i-As efflux systems and the production of phytochelatins (PCs) to complex i-As. Our study focused on the identification and quantification of phytochelatins by HPLC-ICP-MS/ESI-MS, relating them to the several variables linked to As exposure. GSH, 11 PCs, and AsâPC complexes from the roots of six rice cultivars (Italica Carolina, Dom Sofid, 9524, Kitrana 508, YRL-1, and Lemont) exposed to low and high levels of i-As were compared with total, i-As, and o-As in roots, shoots, and grains. Only Dom Sofid, Kitrana 508, and 9524 were found to produce higher levels of PCs even when exposed to low levels of As. PCs were only correlated to i-As in the roots (r=0.884, P <0.001). However, significant negative correlations to As transfer factors (TF) rootsâgrains (r= â0.739, P <0.05) and shootsâgrains (r= â0.541, P <0.05), suggested that these peptides help in trapping i-As but not o-As in the roots, reducing grainsâ i-As. Italica Carolina reduced i-As in grains after high exposure, where some specific PCs had a special role in this reduction. In Lemont, exposure to elevated levels of i-As did not result in higher i-As levels in the grains and there were no significant increases in PCs or thiols. Finally, the high production of PCs in Kitrana 508 and Dom Sofid in response to high As treatment did not relate to a reduction of i-As in grains, suggesting that other mechanisms such as AsâPC release and transport seems to be important in determining grain As in these cultivars
A Systematic Analysis of Metal and Metalloid Concentrations in Eight Zebrafish Recirculating Water Systems
Metals and metalloids are integral to biological processes and play key roles in physiology and metabolism. Nonetheless, overexposure to some metals or lack of others can lead to serious health consequences. In this study, eight zebrafish facilities collaborated to generate a multielement analysis of their centralized recirculating water systems. We report a first set of average concentrations for 46 elements detected in zebrafish facilities. Our results help to establish an initial baseline for trouble-shooting purposes, and in general for safe ranges of metal concentrations in recirculating water systems, supporting reproducible scientific research outcomes with zebrafish
Investigation into mercury bound to biothiols: structural identification using ESIâion-trap MS and introduction of a method for their HPLC separation with simultaneous detection by ICP-MS and ESI-MS
Mercury in plants or animal tissue is supposed to occur in the form of complexes formed with biologically relevant thiols (biothiols), rather than as free cation. We describe a technique for the separation and molecular identification of mercury and methylmercury complexes derived from their reactions with cysteine (Cys) and glutathione (GS): Hg(Cys)2, Hg(GS)2, MeHgCys, MeHgGS. Complexes were characterised by electrospray mass spectrometry (MS) equipped with an ion trap and the fragmentation pattern of MeHgCys was explained by using MP2 and B3LYP calculations, showing the importance of mercuryâamine interactions in the gas phase. Chromatographic baseline separation was performed within 10Â min with formic acid as the mobile phase on a reversed-phase column. Detection was done by online simultaneous coupling of ES-MS and inductively coupled plasma MS. When the mercury complexes were spiked in real samples (plant extracts), no perturbation of the separation and detection conditions was observed, suggesting that this method is capable of detecting mercury biothiol complexes in plants
A herbivore tag-and-trace system reveals contact- and density-dependent repellence of a root toxin
Foraging behavior of root feeding organisms strongly affects plant-environment-interactions and ecosystem processes. However, the impact of plant chemistry on root herbivore movement in the soil is poorly understood. Here, we apply a simple technique to trace the movement of soil-dwelling insects in their habitats without disturbing or restricting their interactions with host plants. We tagged the root feeding larvae of Melolontha melolontha with a copper ring and repeatedly located their position in relation to their preferred host plant, Taraxacum officinale, using a commercial metal detector. This method was validated and used to study the influence of the sesquiterpene lactone taraxinic acid ÎČ-D-glucopyranosyl ester (TA-G) on the foraging of M. melolontha. TA-G is stored in the latex of T. officinale and protects the roots from herbivory. Using behavioral arenas with TA-G deficient and control plants, we tested the impact of physical root access and plant distance on the effect of TA-G on M. melolontha. The larvae preferred TA-G deficient plants to control plants, but only when physical root contact was possible and the plants were separated by 5 cm. Melolontha melolontha showed no preference for TA-G deficient plants when the plants were grown 15 cm apart, which may indicate a trade-off between the cost of movement and the benefit of consuming less toxic food. We demonstrate that M. melolontha integrates host plant quality and distance into its foraging patterns and suggest that plant chemistry affects root herbivore behavior in a plant-density dependent manner. © 2017, Springer Science+Business Media New York
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