How some plants spread their seeds: Ready, set, catapult

November 02, 2010

Catapults are often associated with a medieval means of destruction, but for some plants, they are an effective way to launch new life. Dispersing seeds greater distances by catapulting can provide selective advantages, including the establishment of populations in new environments and escape from certain threats.

In new work published in the recent October issue of American Journal of Botany (http://www.amjbot.org/cgi/reprint/97/10/1595), Dr. David J. Ellerby, students, and postdoctoral researcher Shannon Gerry at Wellesley College measured the mechanics involved in catapulting seeds for the ballistic disperser Cardamine parviflora.

"While plants are generally thought of as immobile organisms, many of them are capable of spectacularly rapid movements," stated Ellerby. For C. parviflora, the valves of the silique rapidly coil outward catapulting the seeds away from the parent plant. The entire coiling and launching process is completed in around 5 msec--faster than the blink of an eye.

Analysis of the launch showed that the catapulting mechanism is not very reliable in C. parviflora, with the majority of the seeds simply falling to the ground. For the seeds that were launched, however, the transference of stored energy to kinetic energy was ~20% efficient. An impressive number when compared to the 0.5% efficiency observed for a ballistic diplochore (Impatiens capensis) in a previous study of Ellerby and colleagues.

This incredible speed and high energy storage present a challenge for the researchers. "These seed pod catapults are on a hair trigger," said Ellerby. "Successfully positioning them in front of our high-speed camera without them exploding prematurely requires an incredibly steady hand."

Seed launching has evolved in a number of groups. Comparing the mechanics of seed dispersal and the morphology of fruits and seeds between plants utilizing ballistic methods and closely related plants that do not, can provide a deeper understanding of the evolution of ballistic mechanisms and the properties required for energy storage and transference.

Seed dispersal has been studied extensively in the model plant Arabidopsis thaliana, a close relation to Cardamine. Like most other members of the Brassicacae, A. thaliana does not disperse its seeds via catapulting. Instead, the seeds are dropped to the ground as the silique dehisces and splits. Despite these differences in seed dispersal mechanisms, the siliques of C. parviflora and A. thaliana are morphologically similar. One difference is the persistence of second layer on the inner surface of the valve in C. parviflora that degenerates in A. thaliana during maturation. This additional layer likely plays a role in valve coiling.

"Ultimately it will be important to analyze the spring-structures at a tissue and cellular level to determine precisely how they store such impressive amounts of energy," Ellerby said. "This could inform the design of human-engineered structures for absorbing or storing elastic energy."
-end-
CITATION: Marika Hayashi, Shannon P. Gerry, and David J. Ellerby (2010). The seed dispersal catapult of Cardamine parviflora (Brassicaceae) is efficient but unreliable. American Journal of Botany 97(10): 1595-1601. DOI: 10.3732/ajb.1000173

The full article in the link mentioned is available for no charge for 30 days following the date of this summary at http://www.amjbot.org/cgi/reprint/97/10/1595. After this date, reporters may contact Richard Hund at ajb@botany.org for a copy of the article.

The Botanical Society of America (www.botany.org) is a non-profit membership society with a mission to promote botany, the field of basic science dealing with the study and inquiry into the form, function, development, diversity, reproduction, evolution, and uses of plants and their interactions within the biosphere. It has published the American Journal of Botany (www.amjbot.org) for nearly 100 years. In 2009, the Special Libraries Association named the American Journal of Botany one of the Top 10 Most Influential Journals of the Century in the field of Biology and Medicine.

For further information, please contact the AJB staff at ajb@botany.org.

Botanical Society of America

Related Energy Storage Articles from Brightsurf:

Reviewing multiferroics for future, low-energy data storage
Big data and exponential demands for computations are driving an unsustainable rise in global ICT energy use.

The perfect angle for e-skin energy storage
Researchers at DGIST have found an inexpensive way to fabricate tiny energy storage devices that can effectively power flexible and wearable skin sensors along with other electronic devices, paving the way towards remote medical monitoring & diagnoses and wearable devices.

Upcycling plastic waste toward sustainable energy storage
UC Riverside engineering professors Mihri and Cengiz Ozkan and their students have been working for years on creating improved energy storage materials from sustainable sources, such as glass bottles, beach sand, Silly Putty, and portabella mushrooms.

Chemists advance solar energy storage aimed at global challenges
Multi-university effort develops solar energy storage to enable decentralized electrification systems in remote areas.

Energy-saving servers: Data storage 2.0
A research team of Mainz University has developed a technique that will potentially halve the energy required to write data to servers and make it easier to construct complex server architectures.

Energy storage using oxygen to boost battery performance
Researchers have presented a novel electrode material for advanced energy storage device that is directly charged with oxygen from the air.

New material, modeling methods promise advances in energy storage
The explosion of mobile electronic devices, electric vehicles, drones and other technologies have driven demand for new lightweight materials that can provide the power to operate them.

Finding balance between green energy storage, harvesting
Generating power through wind or solar energy is dependent on the abundance of the right weather conditions, making finding the optimal strategy for storage crucial to the future of sustainable energy usage.

Diamonds shine in energy storage solution
QUT researchers have proposed the design of a new carbon nanostructure made from diamond nanothreads that could one day be used for mechanical energy storage, wearable technologies, and biomedical applications.

Gas storage method could help next-generation clean energy vehicles
A Northwestern University research team has designed and synthesized new materials with ultrahigh porosity and surface area for the storage of hydrogen and methane for fuel cell-powered vehicles.

Read More: Energy Storage News and Energy Storage Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.