Evolutionarily conserved phenylpropanoid pattern on angiosperm pollen

The male gametophyte of higher plants appears as a solid box containing the essentials to transmit genetic material to the next generation. These consist of haploid generative cells that are required for reproduction, and an invasive vegetative cell producing the pollen tube, both mechanically protected by a rigid polymer, the pollen wall, and surrounded by a hydrophobic pollen coat. This coat mediates the direct contact to the biotic and abiotic environments. It contains a mixture of compounds required not only for fertilization but also for protection against biotic and abiotic stressors. Among its metabolites, the structural characteristics of two types of phenylpropanoids, hydroxycinnamic acid amides and flavonol glycosides, are highly conserved in Angiosperm pollen. Structural and functional aspects of these compounds will be discussed.