Winged Seeds Boost Sprouting Speed in a Flower Species

Greg Howard
24th January, 2024

Winged Seeds Boost Sprouting Speed in a Flower Species

White Buttons (Anacyclus clavatus)

Photo adapted from: Francisco Gómez Prieto / CC BY (Source)
For decades, scientists believed that the wing-like structures on some fruits existed solely to aid in seed dispersal – helping seeds travel further from the parent plant. However, recent research from Universidad Rey Juan Carlos challenges this long-held assumption, suggesting these wings may have a secondary, and potentially equally important, role: accelerating germination. The core of the issue lies in understanding how seeds ‘wake up’ and begin to grow. Germination requires water, and the speed at which a seed absorbs water can significantly impact its success. Some plants produce different types of seeds – a phenomenon called heterocarpy – with varying characteristics, including the presence or absence of wings[2]. Previous work on heterocarpic species like Crepis sancta demonstrated that seeds with different morphologies often germinate at different times, with earlier germination frequently leading to better plant performance[3]. This raised the question of why these differences in germination timing existed, and whether it was simply a byproduct of other traits, or an adaptation in itself. The study[1] focused on Anacyclus clavatus, a plant that produces both winged and unwinged fruits. Researchers investigated whether the wings influenced how quickly the fruits absorbed water, and how this, in turn, affected germination. They found that winged fruits absorbed water significantly faster than their unwinged counterparts. To test if this faster absorption was crucial, they manipulated the wings – either reducing their size or completely sealing them with wax to prevent water uptake. The results were clear. Cutting the wings didn’t significantly alter germination time, suggesting the wing’s size itself wasn’t the key factor. However, sealing the wings did delay germination. This indicated that the wings weren’t just about physical structure, but about facilitating water absorption. Further experiments confirmed this. When water was scarce, unwinged fruits struggled to germinate, but the winged fruits continued to germinate at a normal rate. These findings build upon earlier research showing that germination timing can be more important for plant success than seed size or other inherent traits[2]. The study suggests that the wings aren’t necessarily about how far a seed travels, but about how quickly it can get started once it lands. This challenges the traditional view of a simple trade-off between dispersal and competitive ability, where larger, non-dispersing seeds were thought to have a competitive advantage solely due to their size[3]. Instead, it suggests that early germination, facilitated by the wings, can provide that competitive edge. Interestingly, this research also touches upon findings from studies on oak trees (Quercus ilex) which showed that larger seeds, while having some benefits, are also more vulnerable to predation[4]. This highlights the complex interplay of factors influencing seed survival – it’s not always about being the biggest, but about finding the right balance between dispersal, germination speed, and avoiding predators. The Universidad Rey Juan Carlos study proposes a new understanding of fruit wings: they aren’t just for flight, they’re for hydration. By increasing the surface area for water absorption, wings help seeds overcome a critical hurdle to successful germination, potentially improving seedling establishment and overall plant fitness.

FruitsPlant Science

References

Main Study

1) Fruit wings accelerate germination in Anacyclus clavatus.

Published 21st January, 2024

https://doi.org/10.1002/ajb2.16272

Related Studies

2) The effects of achene type and germination time on plant performance in the heterocarpic Anacyclus clavatus (Asteraceae).

https://doi.org/10.3732/ajb.1400030

3) Competition/colonization syndrome mediated by early germination in non-dispersing achenes in the heteromorphic species Crepis sancta.

https://doi.org/10.1093/aob/mcs203

4) Bigger is not always better: conflicting selective pressures on seed size in Quercus ilex.

Journal: Evolution; international journal of organic evolution, Issue: Vol 58, Issue 1, Jan 2004


Related Articles

An unhandled error has occurred. Reload 🗙