4. Conclutions
Using CQDs as fluorescent probes, we analyzed the changes of carboxylated biomolecules in the growth and metabolism of Microcystis aeruginosa by covalent coupling method, mainly including the changes of GSH, phycocyanin and SOD enzymes in microalgae. The changes of GSH content in Microcystis aeruginosa at different growth stages and the correlation between phycocyanin, SOD enzymes and GSH in algal cells were analyzed from one-dimensional, two-dimensional and three-dimensional fluorescence, respectively. The correlation was good, and the number of peaks and peak area of GSH content in the three-dimensional fluorescence spectral region were changed, and the GSH content in the algal cells reached the maximum at the 50th day. The GSH content of both phycocyanin and SOD enzyme reached the maximum at day 65, and there was no other interference in the system; GSH plays an important role in reducing the external oxidative damage of microalgae cells. The interaction between GSH synthesis, GSH/GSSG interconversion, synthesis of phytochelating peptide (PC), ASA-GSH cycle and metabolism in Microcystis aeruginosa, and the simultaneous linear changes between GSH and phycocyanin, SOD enzyme changes all the time, played a key role in maintaining the antioxidant properties of microalgae during the growth of microalgae and in regulating redox-sensitive signaling. It plays a key role in the regulation of redox-sensitive signaling during microalgal growth.