top of page

Earth's First Plants Likely to Have Been Branched


Selaginella. Credit: Vicky Spencer
Selaginella. Credit: Vicky Spencer

Scientists at the University of Bristol have made a new discovery that has the potential to change ideas about the origin of branching in plants. Through studying the mechanisms responsible for branching, the team has determined what the first land plants are likely to have looked like millions of years ago. This article will discuss the team's findings and what it means for our understanding of the evolution of plant life.


Branching in Vascular Plants


Unlike flowering plants, other vascular plants branch by splitting the shoot apex into two during growth, a process known as 'dichotomy.' Dr. Jill Harrison from Bristol's School of Biological Sciences explained that diverse shapes abound in the dominant flowering plant group. Gardeners will be familiar with 'pinching out' plants' shoot tips to stimulate side branch growth, leading to a bushier overall form. The team's research has identified a common mechanism for branching in vascular plants.


Regulation by Auxin Transport


Using surgical experiments in a lycophyte, researchers at the University of Bristol have discovered that dichotomy is regulated by short-range auxin transport and coordinated in different parts of the plant by long-range auxin transport. The findings that both flowering plant and lycophyte branching are regulated by auxin transport imply that similar mechanisms were present in the earliest vascular plants around 420 million years ago.



What the First Land Plants Looked Like


By combining these findings with discoveries made in the non-vascular, non-branching moss group, we can infer what the first land plants looked like around 480 million years ago. Previously, Dr. Harrison's lab disrupted auxin transport in a moss, leading it to branch in a similar manner to the earliest branching fossils. Together, these studies imply that the earliest land plants were branched, and that branching was lost during the evolution of non-vascular mosses.


Importance of Branching


Dr. Jill Harrison explained that the greening of the land by plants paved the way for all terrestrial life to evolve as it provided food for animals and oxygen to breathe, and branching was a key innovation in the radiation of land plants. The team's work implies that branching evolved earlier than thought, which is an important evolutionary conclusion. Furthermore, the fact that the team has shown that plants that are so distantly related use the same genetic mechanisms to regulate branching brings great potential to transfer knowledge in engineering plant shape to improve future productivity and yield.


Journal Information: Victoria M. R. Spencer et al, Diverse branching forms regulated by a core auxin transport mechanism in plants, Development (2023). DOI: 10.1242/dev.201209
4 views0 comments

Recent Posts

See All
bottom of page