APR 23, 2014 12:00 AM PDT

Plant Bud Growth and Branching Initiated by Sugar

WRITTEN BY: Jen Ellis
For years, botanists had assumed that a specific plant hormone called auxin was the primary driver determining branching and bud growth in plants. However, a research group from the University of Queensland has countered this theory with a study that was published recently in the Proceedings of the National Academy of Sciences. They have determined that the true driving force is plant sugars.

The team cooperated with a group at Brookhaven National Laboratory to create a radioactive tracer for the sugars through a mostly natural process. By exposing the plants to carbon dioxide formed with carbon-11 isotope, a traceable sugar was created through the absorption of the modified carbon dioxide by the plants and the subsequent natural photosynthesis process.

Once the traceable sugar was created, its progress through the plant could be tracked over time, accumulation points could be identified, and rates of travel throughout the plant could be calculated. The team found that in response to clipping, the transport rate of sugar to the buds was greatly increased. Bud outgrowth was increased proportionately.

However, the auxin that was previously thought to be the dominant factor migrated toward the buds at a much slower rate. The branching process can begin up to a full day before changes are detected in the auxin levels.

Meanwhile, sugar traveled at a rate of 150 centimeters per hour throughout the plant stem-approximately 100 times the rate of auxin-and was determined to be the initiator for bud growth. Auxin still plays a role in the branching and bud growth process; it just turns out to be a non-dominant role and occurs at a later stage.

This work backs up the premise that growth of buds in the lower branches of plants are reduced because of the needs of the active shoots in upper branches, depriving the lower branches of the sugar required for increased bud growth. By intentionally clipping upper shoots, the growth and branching is increased at the lower levels through redistribution of the necessary sugars.

There are several logical areas for follow-up research-for example, for tree-based crops such as apples, an understanding of how the sugar is divided and transported between growth of the tree and production of fruit can result in better management of fruit trees and greater yields of fruit.

Plant growth optimization could be used in other fields, such as energy. The Office of Science within the U.S. Department of Energy funded this work in their Brookhaven facility to improve bioenergy production.

For example, optimized growth and branching in crops like sorghum and switchgrass could improve the overall economics of using them to produce biofuel. In those two cases, the new shoots and buds aren't readily accessible for this type of testing, but the University of Queensland/Brookhaven joint effort and similar research is assumed to transfer over to these potential cash crops.

We look forward to more cutting edge research from this team, and we are anxious to see their current work integrated into the field.
About the Author
You May Also Like
DEC 03, 2019
Earth & The Environment
DEC 03, 2019
Small forests provide key ecosystem services
Due to human expansion in agriculture and livestock, logging, gas and oil exploration, and infrastructure expansion, forests today are more fragmented than...
DEC 16, 2019
Genetics & Genomics
DEC 16, 2019
A New Threat to Christmas Trees is Discovered
Fraser firs are farmed to supply us with great-smelling Christmas trees that hold their needles, but they are also susceptible to molds....
JAN 29, 2020
Earth & The Environment
JAN 29, 2020
New Study Suggests Phytoplankton Will Thrive, not Decline
Based on current Earth models, which project warming seas and nutrient depletion, scientists widely believe that phytoplankton biomass will decline in...
FEB 12, 2020
Earth & The Environment
FEB 12, 2020
Urban Heat-Islands Mistakenly Signal Spring to Trees
Have you noticed trees and other vegetation in your city turning green earlier than usual? A new study from Iowa State University has shown that urban land...
FEB 11, 2020
Plants & Animals
FEB 11, 2020
How the World's Fastest Cat Compares to the World's Fastest Dog
Cheetahs are the world’s fastest land animal; their powerful hind legs give them incredible launching power and their stretchy spines provide a massi...
FEB 23, 2020
Plants & Animals
FEB 23, 2020
When a Young Chick Fails to Fly, it Must Fight for its Life
Young Guillemot chicks are eventually pushed from the safety of their rocky ledges when their parental units believe they’re big enough to fly for th...
Loading Comments...