Cadmium (Cd) causes serious damage to plants. Although calcium (Ca) signal has been found to respond to certain stress, the localization of Ca and molecular mechanisms underlying Ca signal in plants during Cd stress are largely unknown. In this study, Ca2+-sensing fluorescent reporter (GCaMP3) transgenic duckweed showed the Ca2+ signal response in Lemna turionifera 5511 (duckweed) during Cd stress. Subsequently, the subcellular localization of Ca2+ has been studied during Cd stress by transmission electron microscopy,...