AMF-mediated modulation of growth and chlorophyll content in two ornamental plant species under lead stress

Lead (Pb) contamination in soil presents a major threat to plant health and ecosystem integrity, particularly in urban areas with ornamental plants. Arbuscular mycorrhizal fungi (AMF) mitigates heavy metal toxicity, but comparative data across ornamental species are limited. This study investigated Rhizophagus irregularis effects on Pb uptake and physiological traits in ornamental cabbage (Brassica oleracea) and gladiolus (Gladiolus grandiflorus) under five Pb levels (0-200 mg Pb/kg soil) in a greenhouse using a factorial experimental design. Results showed that AMF reduced Pb translocation from roots to shoots in both species. At 200 mg/kg Pb, root Pb concentrations decreased from 67.8 ± 3.2 mg/kg to 54.6 ± 2.9 mg/kg in ornamental cabbage, and from 63.2 ± 3.0 mg/kg to 51.7 ± 2.8 mg/kg in gladiolus due to AMF inoculation. Chlorophyll content and shoot biomass also declined less severely in AMF-treated plants. Notably, gladiolus plants exhibited higher AMF colonization (70.2% at 0 mg/kg Pb) and maintained greater stability in growth and chlorophyll content than ornamental cabbage, indicating a species-specific variation in symbiotic efficiency and Pb stress tolerance. These results highlight species-specific benefits of AMF under Pb stress and underscore the potential of integrating diverse ornamental and crop species in phytoremediation strategies based on their symbiotic compatibility.