Invasive Species Compendium

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Abstract Full Text

Growth, physiological and ecological responses of invasive plant Flaveria bidentis to Cd stress.

Abstract

To clarify the ecological adaptability of the invasive plant Flaveria bidentis to heavy metal-contaminated habitats, we simulated habitats with different concentrations of cadmium (Cd) by pot experiments, and the plasticity of responses of growth, and physiological and ecological characteristics as well as heavy metal enrichment characteristics in response to the environmental stress were studied. Additionally, the tolerance mechanisms of plant were further explored. The results showed that high concentration heavy metal treatment (8 mg.kg-1) significantly inhibited the growth and biomass of Flaveria bidentis, both of which showed a decreasing trend with the increase of Cd concentration; The content of malondialdehyde (MDA) and the fluorescence intensity of DCF increased gradually with the increase of Cd concentration, which indicated the active oxygen content increased. Under low (2 mg.kg-1) and medium (4 mg.kg-1) concentrations of cadmium, the Flaveria bidentis reduced its active oxygen content by increasing superoxide dismutase (SOD), peroxidase (POD)and catalase (CAT) activities. However, the activities of antioxidant enzymes decreased under the high concentration (8 mg.kg-1) treatment; The content of Cd in the tissues of Flaveria bidentis showed the rule of root > leaf > stem. With the increase of Cd concentration, the content of heavy metals in the tissues increased gradually, and the Cd concentration and transfer coefficient in the roots and aboveground parts increased first and then decreased. Under heavy metal stress, the phenotypic plasticity index (PPI) of root biomass, leaf biomass and heavy metal enrichment of Flaveria bidentis was higher (>0.5), which indicated that Flaveria bidentis may accumulate nutrients mainly through root and leaf biomass processes, and regulate the enrichment and transfer of heavy metals in the body to adapt to heavy metal polluted habitats.