The contents of risk elements, arsenic speciation, and possible interactions of elements and betalains in beetroot (Beta vulgaris, L.) growing in contaminated soil

Abstract

Abstract:The effect of enhanced soil risk element contents on the uptake of As, Cd, Pb, and Zn was determined in two pot experiments.Simultaneously, transformation of arsenic and its compounds in beetroot (Beta vulgaris L.) plants was investigated. The mobile fractions of elements were determined in 0.05 mol L -1 (NH 4 ) 2 SO 4 extracts and did not exceed 2% of total soil arsenic, 9% of total cadmium, 3% of total lead, and 8% of total zinc, respectively. Although the soils were extremely contaminated the mobile portions of the elements represented only a small fragment of the total element content. Arsenic contents in beet plants reached up to 25 mg As kg -1 in roots and 48 mg As kg -1 in leaves in the soil characterized by the highest mobile arsenic portion. Arsenic portions extractable with water and phosphate buffer from the beetroot samples did not show significant differences between the extraction agents but the extractability was affected by the arsenic concentration. Arsenic was almost quantitatively extractable from the samples with the lowest total arsenic concentration, whereas in the samples with the highest total arsenic concentration less than 25% was extractable. Arsenate was the dominant arsenic compound in the extracts (70% in phosphate buffer, 50% in water extracts). A small portion of dimethylarsinic acid, not exceeding 0.5%, was detected only in the sample growing in the soil with the highest arsenic concentration. The role of betalains (betanin, isobetanin, vulgaxanthin I and vulgaxanthin II) in transformation/detoxification of arsenic in plants was not confirmed in this experiment because the plants were able to grow in the contaminated soil without any symptoms of arsenic toxicity.

Arsenic Toxicity: The Effects on Plant Metabolism

“…In a study on sunflower, 15–20% of the total tissue As was not recovered from the plant tissue, depending on the tissue and post-harvest storage time (Raab et al, 2005 ). In beetroot, As was nearly quantitatively extractable from tissues with low As burden, but in tissues with higher As burdens, up to 75% of the As was not extracted (Száková et al, 2010 ). Perhaps the speciation of this missing As, or indeed the molecules to which it may be bound, will give us important insights into the underlying mechanism of As toxicity.…”

The effect of soil risk element contamination level on the element contents in Ocimum basilicum L.

“…Rubrum) cultivated in copper-enriched medium (Posmyk et al 2009). Although the functions of betalains are analogous to anthocyanins, the potential role of betalains (betanin, isobetanin, vulgaxanthin I and vulgaxanthin II) in transformation/detoxifi cation of arsenic in beetroot (Beta vulgaris) was not confi rmed (Száková et al 2010). …”

New Green Determination of Cu, Fe, Mn, and Zn in Beetroot Juices along with Their Chemical Fractionation by Solid-Phase Extraction

“…In this case, however, the health-promoting effects of beetroots result not only from the intake of high amounts of the mentioned macro- and microelements but primarily from the beneficial concentration ratios of selected minerals in these vegetables, particularly K to Mg, Ca to Mg, and K to the sum of Mg and Ca [1]. In reference to this, the elemental analysis of beetroots by the atomic spectrometry methods has to be carried out to possess the crucial information on their mineral composition, the levels of the accumulated trace metals that could pose a threat to their quality and safety, and any changes in the concentrations of the selected metals due to the applied cultivation methods or cultivars [1,8,10,11,12,13,14].…”