Analysis of the effects of cerium on calcium ion in the protoplasts of <i>Arabidopsis thaliana</i> with confocal microscopy

Abstract

The laser-scanning confocal microscopy has become a routine technique and indispensable tool for cell biological studies. In this study, the probe Fluo-3 AM was used to research the instantaneous changes of calcium ion (Ca²⁺) in the protoplasts of Arabidopsis thaliana. The laser-scanning mode of confocal microscope is XYT, and the time interval between two images is 10.635 s. 30 optical sections were acquired with the laser-scanning confocal microscope, and the different concentrations of trivalent cerium (Ce³⁺) (0.1, 0.5 and 1.0 mmol/L) were added after four optical sections were scanned, respectively. Furthermore, the fluorescence intensity of Ca²⁺ in the 30 optical sections was quantified with Leica Confocal Software. The quantitative data was exported and the trend chart was made with Excel software. The results indicate that Ca²⁺ concentration in the protoplasts of A. thaliana declined after 0.5 and 1.0 mmol/L Ce³⁺ was added. However, Ca²⁺ concentration slightly increased in the protoplasts treated with 0.1 mmol/L Ce³⁺. The data indicate that the appropriate amount of Ce³⁺ can inhibit intracellular Ca²⁺ concentration in the protoplasts of A. thaliana. Since Ca²⁺ participates in signal transduction and plays a crucial role in regulating plant growth and development under environmental stresses, Ce³⁺ may regulate plant metabolism, growth and development via the changes of Ca²⁺ concentration.

Key words: Cerium, calcium ion, protoplast, confocal microscope.