Phytotoxicity of tetrabromobisphenol A on rice and measure for toxicity alleviation

Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant, is bioaccumulative and tends to accumulate in organisms, leading to potential toxic effects. Although extensive studies have been conducted on TBBPA's toxicity to animals, its effects and mechanisms in plants, the primary producers in ecosystems, are still unclear. Investigating the phytotoxicity of TBBPA is crucial for assessing environmental risks and potential human health impacts. Therefore, in this study, rice seedlings were hydroponically exposed to TBBPA at four concentrations (5-5000 µg/L) that are environmentally relevant or slightly higher than environmental levels for 7 days. Physiological parameters, oxidative stress markers, nutrient uptake and special distributions were analyzed. TBBPA significantly impacted on the nutrient uptake and rice growth at low exposure concentrations. Some indicators, such as the pigment contents, showed low-dose stimulatory effect as the alleviation measures of plant themselves. At high exposure concentrations (5000 µg/L), visible rust spots on shoots, severe oxidative damage to roots (the malondialdehyde (MDA) level was 284 % higher than blank group), and disrupted nutrient contents (K, P, B) in both roots and shoots were observed. Phosphorus supplementation effectively mitigated these toxic effects, restoring leaf condition and nutrient uptake. After phosphorus supplementation, P, Ca, Zn, Fe, and Cu showed significant increases by 1, 0.8, 0.6, 0.6, and 2 folds, respectively. Our study deepens the understanding of plant responses to TBBPA and offers an effective strategy to manage TBBPA contamination in agricultural systems and safeguarding environmental and public health.