Arsenic impact in the xero-halophyte plant species Atriplex atacamensis Phil. at the seedling stage
(2018)
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- Authors
- Supervisors
- Lutts, Stanley
- Abstract
- Arsenic (As) is a toxic metalloid ubiquitously present in the environment and which threaten human health in numerous areas in the world. Atriplex atacamensis, is an endemic xero-halophyte plant species of Northern Chile found close to the Atacama Desert where arsenic contamination frequently occurs mainly due to mine waste and volcanic sediments. This region is also characterized by high salinity. The global aim of our study is to analyze the physiological behavior of A. atacamensis exposed to toxic doses of As in order to quantify its level of resistance and to decipher its mechanisms of tolerance to this toxic element. A field analysis confirmed the presence of high As doses in the soil and in the water collected from Rio Loa in North Chile. Experiments were then performed in nutrient solution on seedlings issued from seeds collected on mature plants and confirmed that young seedlings were able to cope with high As doses (up to 1000 µM). Both As(V) and As(III) were detected within plant tissues. Addition of NaCl increased As translocation from the root to the shoot and the proportion of endogenous As(V) comparatively to As(III). In contrast, phosphate deficiency reduced As translocation. Arsenic did not induce any water stress at the plant level and As was not excreted by the leaf trichomes. Beside osmoprotectant (proline, glycinebetaine), polyamines may also afford protection in response to As toxicity. External As(III) was more toxic than As(V) at both the whole plant and cell levels. As content in the roots (up 5000 µg.g-1) were at least 10 times higher than in old leaves and approximately 50 times higher than in young leaves. The root As accumulation and cell wall sequestration appeared to be efficient strategies for As resistance. Oversynthesis of phytochelatin plays a key role in plant protection against accumulated As. Atriplex atacamensis is considered as a promising tool for the phytomanagement of As-contaminated areas in arid regions.
- Affiliations
Citations
Vromman, D. (2018). Arsenic impact in the xero-halophyte plant species Atriplex atacamensis Phil. at the seedling stage. https://hdl.handle.net/2078.5/127418