As chemical messengers, phytohormones can enhance the tolerance of plants to stress caused by toxic elements (TEs) such as cadmium (Cd), lead (Pb), and zinc (Zn). This study investigated the combined toxicity of Cd, Pb, and Zn, and its impact on stress phytohormones (jasmonates, salicylic acid, and abscisic acid), in oat (Avena sativa L.) using anthropogenically contaminated soil in a 4-week pot experiment. The uptake of TEs by the roots increased in the multi-contaminated soil, while Zn was the only TE to be translocated to the leaves. The toxic effect of the TEs was assessed in terms of plant growth, revealing a decline in leaf dry biomass, whereas the impact on the roots was insignificant. These findings align with the levels of stress phytohormones. An increase in bioactive forms of stress phytohormones in leaves due to TEs indicates TE toxicity and leaf sensitivity. Conversely, low levels of these phytohormones, along with crosstalk between them, suggest reduced defense against TEs in the roots. The abundance of stress phytohormones declined in the following order: salicylic acid > jasmonates > abscisic acid. These results help to understand the mechanism by which plants respond to TEs, particularly their combined toxicity.

• Keywords
• abscisic acid, jasmonic acid, oat, potentially toxic elements, salicylic acid, stress response,
• Publication type
• Journal Article MeSH

This study investigated the metabolic adaptive responses to As contamination and As co-contamination with cadmium, lead, and zinc in the leaves and tubers of cherry radish (Raphanus sativus var. sativus Pers.). The response was assessed by measuring malondialdehyde levels, total phenolic content (TPC), total anthocyanin pigment (TAC), growth and stress phytohormone concentration, and free amino acid content. The characteristic As accumulation of single contamination resulted in a decrease in tuber growth. However, in the case of co-contamination, As uptake was influenced by the presence of other potentially toxic elements (PTEs), mainly zinc, with no significant effect on growth. Both contaminated treatments exhibited significant differences in metabolite levels among the organs, along with notable changes in their contents. Increases in malondialdehyde, TPC, and TAC indicated induced oxidative stress and an antioxidant response that was more pronounced by As co-contamination. Also, the results for phytohormones, which showed both increases and decreases, along with selected free amino acids (which showed increases), demonstrated a more significant influence of As co-contamination. Based on these findings, it can be concluded that the response of cherry radish to contaminated treatments exhibited significant differences in the studied parameters, along with variability in the results, reflecting the extent of the effects of PTEs that induce oxidative stress.

• Keywords
• amino acids, hormones, metalloid, stress, vegetable,
• MeSH
• Amino Acids * metabolism   MeSH
• Arsenic * toxicity   MeSH
• Soil Pollutants toxicity   MeSH
• Plant Leaves metabolism   drug effects   MeSH
• Malondialdehyde metabolism   MeSH
• Oxidative Stress drug effects   MeSH
• Raphanus * metabolism   drug effects   growth & development   MeSH
• Plant Growth Regulators * metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amino Acids * MeSH
• Arsenic * MeSH
• Soil Pollutants MeSH
• Malondialdehyde MeSH
• Plant Growth Regulators * MeSH

The effects of zinc (Zn) on the physiology of spinach (Spinacia oleracea L.) were investigated in a pot experiment with increasing Zn contents in the horticultural substrate (0, 75, 150, and 300 mg Zn kg-1). Interactions among nutrients in the substrate solution affected plant vitality, biomass yield, and nutrient content in plants. The water-soluble Zn fraction increased with the Zn dose, rising from 0.26 mg kg-1 in the Control to 0.98 mg kg-1 in the Zn300 treatment. The most pronounced effects of elevated Zn content were observed for Ca, Mg, and Mn. In spinach, the dual role of Zn was evident through its impact on yield, particularly regarding aboveground biomass. The positive effects of Zn doses up to 150 mg kg-1 were supported by the tolerance index (TI). In contrast, the 300 mg kg-1 Zn dose exhibited toxic effects, resulting in a 33.3% decrease in the yield of aboveground biomass and a TI value of 0.7. The effects of Zn on nutrient content in aboveground biomass varied with the dose, and the relationship between Zn and P, Fe, Mn, Ca, and K content confirmed a correlation. The toxic effect of the Zn300 treatment was evidenced by a decrease in Ca, Cu, and Fe contents. Additionally, the results of the Zn300 treatment indicated a negative effect on the synthesis of photosynthetic pigments and photosynthesis, likely due to induced oxidative stress. The production of oxalic acid also suggested a toxic effect of the highest Zn dose on spinach.

• Keywords
• hormesis, micronutrient, photosynthesis, spinach, stress, toxicity,
• Publication type
• Journal Article MeSH