Determination of lithium bioretention by maize under hydroponic conditions

Abstract

Irrigation of cultivated plants can be a source of toxic lithium to plants. The data on the effect of lithium uptake on plants are scant, that is why a research was undertaken with the aim to determine maize ability to bioaccumulate lithium. The research was carried out under hydroponic conditions. The experimental design comprised 10 concentrations in solution differing with lithium concentrations in the aqueous solution (ranging from 0.0 to 256.0 mg Li • dm -3 of the nutrient solution). The parameters based on which lithium bioretention by maize was determined were: the yield, lithium concentration in various plant parts, uptake and utilization of this element, tolerance index (TI) and translocation factor (TF), metal concentrations in the above-ground parts index (CI) and bioaccumulation factor (BAF). Depression in yielding of maize occurred only at the highest concentrations of lithium. Lithium concentration was the highest in the roots, lower in the stems and leaves, and the lowest in the infl orescences. The values of tolerance index and EC 50 indicated that roots were the most resistant organs to lithium toxicity. The values of translocation factor were indicative of intensive export of lithium from the roots mostly to the stems. The higher uptake of lithium by the above-ground parts than by the roots, which primarily results from the higher yield of these parts of the plants, supports the idea of using maize for lithium phytoremediation.

Lithium in the Environment and its Effects on Higher Plants

“…McStay et al (1980) reported that Li use in beans significantly increased plant height, first trifoliate fresh weight and leaf area. Antonkiewicz et al (2017) found increased maize yield when using different concentrations of Li under the conditions of nutrient solution to 22.3%.…”

“…Translocation factor increased with increased Li concentration in the nutritive medium, which has lead to similar Li levels in both plant parts. Li concentration was the highest in the roots, lower in the stems and leaves, and the lowest in the inflorescences in maize grown under hydroponic conditions (Antonkiewicz et al, 2017). Li binding in the root can be important regarding the protection from its phytotoxic effect (Aral & Vecchio-Sadus, 2008).…”

“…Li et al (2009) reported that brown-seeded Brassica carinata has some potential in phytoremediation of Licontaminated water and soil. Hawrylak-Novak et al (2012) and Antonkiewicz et al (2017) supported the idea of using maize for rhizofiltration of contaminated water or soil remediation bay phytoextraction. Mycorrhiza is the most widespread association between microorganisms and higher plants (Smith & Read, 2008).…”

“…Li in plants reflects well amount present in the soil. According to Antonkiewicz et al (2017), depending on Li concentration in the nutrient solution, maize utilized between 2 and 24% of Li present in the nutrient medium. The presence of plant-accessible Li increases when soil pH is lower due to decreased negative surface charge and cation-binding sites, which leads to a more intense Li uptake by plants (Aral & Vecchio-Sadus, 2008).…”

“…Individual plant organs show different levels of tolerance to Li. Maize roots were the most resistant organs to Li (Antonkiewicz et al, 2017). Bingham et al (1964) listed a larger number of plant species which had varying sensitivity to Li, and reported that its concentration for normal growth was < 5-10, 6-70 at which 25% growth reduced, and >100 ppm at which growth completely reduced.…”