Influence of silicon on arsenic uptake and toxicity in lettuce
(English)Manuscript (preprint) (Other academic)
Lettuce grown in soil is found to contain high concentration of the toxic element arsenic (As). The aim was therefore to investigate uptake and speciation of As in lettuce as well as the influence of silicon (Si) on As uptake, since Si may diminish the As uptake. Plants were cultivated in nutrient solution containing arsenite or arsenate with or without silicate. Uptake and distribution of As between roots and shoots, As accumulation in cell walls, As speciation and toxic effect on biomass were analysed. Results show that arsenite was more toxic to lettuce than arsenate. Silicate decreased the toxicity to arsenate but very little of the arsenite toxicity was changed by Si. On the other hand, Si diminished the arsenite uptake more than the arsenate uptake. There was higher concentration of arsenate than of arsenite in the plant independent which As species added. When arsenate was added, the As concentration in shoot was half of that in the root and this distribution did not change with Si addition. When arsenite was added, about 10% of As was found in the shoots and 90% in the roots, but changed in the presence of Si to be evenly distributed in the plant. In both roots and shoot, about 40% of the As was found in the cell wall fraction, and only in the shoot when arsenite was added, Si increased this fraction to 47%. The extraction efficiency when analysing the As-species was lower in shoot than in roots, especially in the presence of arsenite and Si. The opposite was found for the As concentration in pellets after extraction. This pointed towards variations in the strength of binding of arsenite and arsenate between roots and shoots and between Si and non-Si treated plants.
Arsenic, accumulation, silicon, speciation, toxicity
Research subject Plant Physiology
IdentifiersURN: urn:nbn:se:su:diva-87793OAI: oai:DiVA.org:su-87793DiVA: diva2:606380