Impact of moderate heat stress on the biochemical and physiological responses of the invasive waterweed Elodea canadensis (Michx. 1803)

Abstract

Global warming can negatively affect freshwater macrophytes. However, the degree to which freshwater plants can survive after long-term or short-term warming and the underlying molecular mechanisms are not fully understood. The aim of our study was to analyze the responses of an invasive plant to moderate heat stress (HS). Biochemical and physiological stress responses to experimental warming (30Ѓ}1.0°C/25Ѓ}1.0°C, day/night) were assessed in the invasive waterweed Elodea canadensis. The effect of the moderate HS on the macrophyte was evaluated through changes in the total protein content, catalase activity, lipid peroxidation, cellular membrane permeability by electrolyte leakage and the concentrations of carotenoids and photosynthetic pigments. Catalase activity and carotenoid concentrations increased significantly (p<0.01) in comparison to the control. A significant increase (p<0.05) in malondialdehyde concentration was observed. However, at the same time there was a persistent low level of electrolyte leakage in heat-treated plants as compared to the control. The results demonstrated that moderate HS improved membrane stability and increased the concentration of photosynthetic pigments and antioxidant activity in E. canadensis shoots. Moderate alterations in temperature may favorably affect the physiology and growth of the invasive macrophyte E. canadensis. It is reasonable to expect that warming could lead to a gradual change in E. canadensis distribution and to changes in composition of freshwater ecosystems.

Keywords

• Elodea canadensis
• antioxidants
• moderate heat stress
• malondialdehyde
• electrolyte leakage