Abstract: Almost all Chinese textbooks of botany have regarded spermatophyte pollen tubes as a key struc-ture for the fertilization independent of water, and concluded that siphonogamy makes seed plants adapt to terrestrial habitats more successfully. In fact, however, certain extinct (pteridosperms and cordaitaleans) and extant (Ginkgo and the cycads) gymnosperms were/are zooidogamous and it is especially noteworthy that they did/do not require the liquid water for their fertilization. Pteridosperms and cordaitaleans had not developed the capacity to produce pollen tubes, while in Ginkgo and the cycads the pollen tube serves as a haustorial organ and does not transfer sperms to the archegonium. It is germination in situ of the microspores within the microsporangium that led to evolutionary formation of pollen and pollination that makes sperms reach ovules without help of any water. The re-understanding of pollen tube function is suggested as a critical teaching case of botany to promote students’ scientific spirit and thinking.
LI Wei-ping. , {{custom_author.name_en}}et al.
Should Fertilization Independent of Water in Spermatophyte Be Attributed to the Origin of Pollen Tube?
Questioning Botany Textbooks (Ⅰ)[J]. Life Science Research, 2021, 25(1): 89-94