Effect of Cadmium-Contaminated Soil on the Growth of Different Ornamental Plants

Abstract

Background and Objective: Soil heavy metal contamination is a major issue caused by different natural factors including erosion, mineral weathering, volcano eruptions and anthropogenic factors such as mining, industrialization, urbanization and fertilizer use that affect plant growth and development. Therefore, the current study was designed to decline the levels of cadmium (Cd) in soil by growing different ornamental plants-Matthiola incana, Antirrhinum majus and Gladiolus grandiflorus.

Materials and Methods: To evaluate how Matthiola incana, Antirrhinum majus and Gladiolus grandiflorus respond to phytoremediation, seedlings were raised in pots according to a Completely Randomized Design (CRD) with a two-factor factorial arrangement. Different doses of Cd (0, 25, 50, 75 and 100 mg L^–¹) were applied after one week of transplanting.

Results: The results revealed that Cd at lower concentrations (25 mg L^–¹) moderately increased the growth parameters (shoot fresh and dry weights, root fresh and dry weights, shoot length and leaf area) compared to higher concentrations (100 mg L^–¹ Cd), showing reductions of 6.72, 19.06 and 21.55% for stock, snapdragon and gladiolus, respectively. Similarly, photosynthetic pigments (total chlorophyll) decreased with the increase of Cd by 6.49, 3.27 and 11.90% for stock, snapdragon and gladiolus at control, respectively. Gaseous exchange parameters (net photosynthesis rate, transpiration rate, stomatal conductance, substomatal conductance and water use efficiency) also decreased with the increase of Cd levels. Antioxidant enzyme activities (catalase, peroxidase and superoxide dismutase) showed similar responses, with changes of 2.4, 1.4 and 23.1% at 25 mg L^–¹ Cd concentration.

Conclusion: It was concluded that all three ornamental plants (Matthiola incana, Antirrhinum majus and Gladiolus grandiflorus) exhibited tolerance to lower Cd concentrations and could be effectively used for phytoremediation of Cd-contaminated soils, as higher Cd levels adversely affected plant growth and physiological attributes.