Leaves and sporangia developed in rare non-Fibonacci spirals in early leafy plants

• 成果类型: Article
• 署名作者: Turner, Holly-Anne; Humpage, Matthew; Kerp, Hans; Hetherington, Alexander J.
• 署名单位: University of Edinburgh; University of Munster; University College Cork
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12311
• DOI: 10.1126/science.adg4014
• 发表日期: 2023-06-16
• 页码: 1188-1192
• 关键词: reproductive-organs; shoot apex; phyllotaxis; EVOLUTION; transitions; morphology; diversity; meristem

摘要

Lateral plant organs, including leaves and reproductive structures, are arranged on stems in distinct patterns termed phyllotaxis. Most extant plants exhibit phyllotactic patterns that are mathematically described by the Fibonacci series. However, it remains unclear what lateral organ arrangements were present in early leafy plants. To investigate this, we quantified phyllotaxis in fossils of the Early Devonian lycopod Asteroxylon mackiei. We report diverse phyllotaxis in leaves, including whorls and spirals. Spirals were all n:(n+1) non-Fibonacci types. We also show that leaves and reproductive structures occurred in the same phyllotactic series, indicating developmental similarities between the organs. Our findings shed light on the long-standing debate about leaf origins and demonstrate the antiquity of non-Fibonacci spirals in plants.