Yan Li is mainly engaged in cell and molecular biology research on plant apical growth and Golgi structure and function. He has presided over 8 projects of the National Natural Science Foundation, and participated in 1 project of the National Natural Science Foundation Innovation Group project, the National Natural Science Foundation key project and the Ministry of Education's "Key Teachers in colleges and Universities Funding Program". In "Plant Cell", "Plant Journal" and other journals published 17 scientific research papers that were included by SCI. How cells keep their transport flowing is one of the 125 most challenging scientific questions posed in the journal Science. The results showed that the microfilament skeleton and myosin XI played a major role in protoplasm flow and organelle movement of plant cells. However, the specific mechanism of plant microfilament skeleton and its motor proteins in the movement of organelles remains to be further studied. By labeling the monomeric actin in the pollen tube, we found that there was a significant monomeric actin concentration gradient in the 10-20 micron region at the top of the pollen tube without microfilament bundles. After Caffeine treatment, the concentration gradient of monomer actin at the top of the pollen tube disappears, and the microfilament bundles move forward to the top of the pollen tube. Therefore, we suggest that the lack of microfilaments at the top of the pollen tube is the result of its depolymerization, and the high concentration of calcium ions at the top of the pollen tube may be an important factor leading to the depolymerization of microfilaments. In addition, we found that the surrounding microfilament bundles are the main mode of existence of the microfilaments in the pollen tube, and speculated that they could provide a track for bidirectional protoplasmic flow (Li et al., 2001). In addition, we found that the formation and maintenance of monomeric actin concentration gradients play an important role in the apical growth of root hair cells (He et al., 2006), and there are also circumferential microfilament bundles in the root hair (Zhang et al., 2014). Recently, our research group found that Arabidopsis myosin Myo11C2 has partial colocalization with pollen tube mitochondria, peroxisome and Golgi apparatus, and plays an important role in mitochondrial movement, distribution, transport and accumulation at the apex of secretory vesicles (Wang et al., 2020). At present, the laboratory is using molecular cell biology techniques to deeply study the molecular mechanism of microfilament skeleton and its motor protein in plant organelle movement and apex growth.