Cellular responses of developing <i>Fucus serratus</i> embryos exposed to elevated concentrations of Cu²⁺

Abstract

ABSTRACT Elevated concentrations of Cu 2+ can have inhibitory effects on early development in plants and algae by targeting specific cellular processes. In the present study the effects of elevated Cu 2+ on developmental processes in embryos of the brown algae Fucus serratus (Phaeophyceae) were investigated. Elevated Cu 2+ was shown to inhibit fixation of the zygotic polar axis but not its formation. Actin localization was unaffected by elevated Cu 2+ but polarized secretion, which occurs downstream, was inhibited. Significant differences in tolerance to Cu 2+ were observed for polarization and rhizoid elongation of embryos derived from adults from Cu 2+ ‐contaminated and uncontaminated locations. Moderate Cu 2+ exposure inhibited the generation of cytosolic Ca 2+ signals in response to hypo‐osmotic shocks. In contrast, cytosolic Ca 2+ was elevated by treatments with high [Cu 2+ ] and this coincided with production of reactive oxygen species. The results indicate that direct effects on signalling processes involved in polarization and growth may in part explain complex, concentration‐dependent effects of Cu 2+ on early development.