Physiological and Biochemical Parameters of Common Duckweed Lemna minor after the Exposure to Tetracycline and the Recovery from This Stress

Abstract

In this study, the ability of Lemna minor L. to recover to normal growth, after being degraded in a tetracycline-containing medium, was extensively investigated. The plants were exposed to tetracycline (TC) at concentrations of 1, 2.5, and 10 mM. Subsequently, their physiological status was analysed against the following criteria: rate of plant growth; free radical accumulation; antioxidant enzyme activity; chlorophyll content; HSP70 protein content; cell membrane permeability, and mitochondrial activity. The study showed that duckweed can considerably recover from the damage caused by antibiotics, within a week of cessation of stress. Of the plant properties analysed, mitochondrial activity was the most sensitive to antibiotic-induced disturbances. After transferring the plants to a tetracycline-free medium, all plant parameters improved significantly, except for the mitochondrial activity in the plants grown on the medium containing the highest dose of tetracycline. In the plants treated with this antibiotic at the concentration of 10 mM, the proportion of dead mitochondria increased and was as high as 93% after one week from the beginning of the recovery phase, even after the transfer to the tetracycline-free medium.

Physiological responses and antibiotic-degradation capacity of duckweed (Lemna aequinoctialis) exposed to streptomycin

“…However, by the end of the experiment, the setups with a higher concentration of streptomycin clearly showed that the fronds had died, suggesting that the antibiotic had a toxic effect on duckweed at a high concentration. This could be explained by the extremely high percentage (93%) of dead mitochondria in duckweed caused by antibiotics in the findings of (Krupka et al, 2021). Maldonado et al (2022) further revealed that the metabolization of antibiotics occurs in three phases in duckweed which contribute to the removal of antibiotics residues in water.…”

The Impact of Soil and Water Pollutants Released from Poultry Farming on the Growth and Development of Two Plant Species

“…A decrease in the content of chlorophyll in plants exposed to anthropogenic environmental factors has been repeatedly observed. The reduction in chlorophyll content in plants treated with antibiotics was demonstrated by Rydzy ński et al [31], Margas et al [89] as well as Krupka et al [38]. However, in most studies assessing the impact of anthropogenic stress factors on chlorophyll, high concentrations of toxic compounds are used.…”

“…The absorbance at λ = 450 nm was measured. In order to compensate for the readings for the natural color of the plant extract, the absorbance was measured at λ = 620 nm, according to Krupka et al [38]. Mitochondrial damage was assessed as a reference (100% viable mitochondria) using the absorbance value of the control sample.…”

“…Lipid peroxidation is a damaging process that affects membrane properties, causes protein degradation, and reduces ion transport capacity, ultimately leading to cell death [95]. Increased levels of MDA have previously been demonstrated in plants treated with antibiotics [38], p,p ′ -DDE [96], and heavy metals. In peas grown on soil taken from the vicinity of the manure heap, the concentration of MDA increased 4-fold (Figure 3A).…”

“…Similar results were obtained with mitochondrial damage (Figure 3B). Mitochondria are organelles that are particularly vulnerable to organic pollutants, including pharmaceuticals [38]. Pesticides also damage the mitochondria.…”