Biodiv Sci ›› 2019, Vol. 27 ›› Issue (11): 1236-1244.DOI: 10.17520/biods.2019160

• Original Papers • Previous Articles     Next Articles

Development of archegonium and oogenesis of the fern Macrothelypteris torresiana

Zhen Zhan,Jianfeng Zhang,Jianguo Cao,Xiling Dai()   

  1. College of Life Sciences, Shanghai Normal University, Shanghai 200234
  • Received:2019-05-10 Accepted:2019-08-12 Online:2019-11-20 Published:2020-01-17
  • Contact: Dai Xiling

Abstract:

Fern oogenesis is a vital process in sexual reproduction, yet Polypodia II oogenesis has not been studied. This paper studies sexual reproduction oogenesis of Macrothelypteris torresiana of Polypodiaceae. Our findings document oogenesis and egg movement throughout sexual reproduction. The appearance of egg envelope, the formation of fertilization pore and nuclear evaginations during the development of Macrothelypteris torresiana are similar to other pteridophytes in eupolypods, and are significantly different from those of the primitive basal groups in leptosporangiates. This indicates that Macrothelypteris torresiana may be a evolutionary fern. Based on the characteristics of the egg envelope and the fertilization pore, we infer that primitive leptosporangiates evolved into polypods after passing through gleicheniales and cyatheales.

Key words: ferns, archegonium, oogenesis, ultrastructure, Macrothelypteris torresiana