Alternating current electrical field effects on lettuce (Lactuca sativa) growing in hydroponic culture with and without cadmium contamination

Abstract

The aim of the present study was to investigate the effect of a 10 Hz alternating current (10 Hz 1 V cm(-1)) and a 50 Hz alternating current (50 Hz 1 V cm(-1)) on the lettuce plant (Lactuca sativa) growing in a hydroponic (soil-free) culture. Thirty lettuce plants were pre-germinated, and then 15 of them were treated with cadmium solution (CdCl2) of 5 mg/L in concentration. Ten plants (five plants with Cd and five plants without Cd) were subjected to a 10 Hz alternating current (AC) electrical field; 10 plants were subjected to a 50 Hz AC field. The rest of the plants were used as a control. The lettuce plants were harvested after a growth of 60 days. The chlorophyll content, biomass and metal content of the lettuce plants were determined. The biomass of the plants growing in non-contaminated medium was 28 and 106% higher under the 10 and the 50 Hz AC fields respectively compared to the control. Although the plant biomass was reduced by the presence of Cd in the growth medium, the biomass of the plants growing in Cd contaminated medium was 40 and 63% higher respectively for 10 and 50 Hz AC field compared to the plant growing in Cd contaminated medium without electrical treatment. Increased uptake of Cd in the plant shoot was found with the 50 Hz AC field. Significant accumulation and uptake of Cu in plant roots and shoots was found under both electrical treatments

Microbial fuel cell driving electrokinetic remediation of toxic metal contaminated soils

“…Beside protons, other cations also could be migrated from the anode to cathode under the electrical field in the MFC [18,19]. It was reported that a very low-level electric field could drive the electromigration of cadmium in the contaminated soil [20]. Several studies also had demonstrated that low voltage electric field could induce movements of nutrients, microorganisms in the contaminated soils [21][22][23].…”

Effect of Electric Field on the Kinetics of Growth of Lettuce (<i>Lactuca sativa</i>) in a Hydroponic System

“…These results are extremely important, since they show the great impact to use a relatively low current intensity to promote an increase in the growth kinetics of lettuces. The most probable cause of this phenomenon can be related to the next issue: the electric external field could alter the pattern of the metabolism in the plant, as well as the process of passive transport of micro and macro elements through the cationic channels [7].…”

“…It was found that the treated plants were greener, more robust and often they showed an important increment in the yield [6]. Bi R. et al, (2010), they investigated the growth of the lettuce in a hydroponic cultivation applying 10 and 50 Hz of alternating current (10 Hz 1 V·cm ), obtaining yields of 28% and 106% respectively compared with the plants that were not subjected to the electric field, the influence of the electric field could last for some time, still after the current has been disconnected, which probably can explain why the plants in the nature are generally green after a day of storm [7]. Myeong et al, (2009) , in terms of: number of leaves, fresh weight and chlorophyll content [8], although according to Mahmoudi et al, (2011) the growth of the lettuce can be affected by a saline stress [9].…”

Sustainable Phytoremediation of Soils Enhanced with Electric Field

“…Cameselle et al [2] have discussed the benefits and limitations of the coupled technology electro-phytoremediation. This technology was proposed to palliate the limitations of phytoremediation [5]. The electric field may enhance the mobilization and transportation of the contaminants towards the roots, increasing not only the bioavailability of the contaminants, but also the bioavailability of nutrients.…”