[The roles of arabinogalactan-proteins in sexual reproduction of angiosperms].

Arabinogalactan-proteins (AGPs) are a class of proteoglycans distributed mainly in the cell surfaces and extracellular matrix of most plants. Their numerous expressions have been detected in many male reproductive organs (pollen, pollen tube and sperm), female reproductive organs (stigma, style and ovary) and embryos (zygotic and somatic embryos) in many plants. Numerous investigations have demonstrated that AGPs are involved in the process of sexual reproduction of angiosperms and play multiple roles, e.g., providing surface adhesion, nutrients and directional cues or signals for pollen tubes. They may also participate in gametal recognition and embryo development and differentiation. But the mechanisms underlying these roles of AGPs are still unclear. Knowledge of AGPs in the structural components, characteristics, expression in reproductive tissues during the process of reproduction are summarized and the mechanisms underlying their functioning are discussed.