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
MAR 19, 2021
Genetics & Genomics
The Giraffe Genome Explains Some of Its Unusual Characteristics
MAR 19, 2021
The Giraffe Genome Explains Some of Its Unusual Characteristics
Giraffes are unique and have made many evolutionary adaptations. They have a very short sleep cycle, for example.
MAR 31, 2021
Plants & Animals
Spring Winds Following Warmer Winters Cause Mass Jellyfish Strandings
MAR 31, 2021
Spring Winds Following Warmer Winters Cause Mass Jellyfish Strandings
Beachgoers are certainly not fond of jellyfish in the water, but seeing hundreds of them wash ashore is an interesting a ...
APR 01, 2021
Microbiology
Mapping the Wild Microbiome to Search for Therapeutic Agents
APR 01, 2021
Mapping the Wild Microbiome to Search for Therapeutic Agents
Many people think of bacteria as disgusting germs, but there are plenty of important bacterial species that provide us w ...
APR 28, 2021
Plants & Animals
Insight Into the Evolution of Madagascar's 'Horned' Crocodile
APR 28, 2021
Insight Into the Evolution of Madagascar's 'Horned' Crocodile
Madagascar is home to many unusual animals. A skull from one - the 'horned' crocodile - can be seen in this image by M. ...
MAY 02, 2021
Cell & Molecular Biology
Coral Cells Can Spit Out the Symbionts They Don't Want
MAY 02, 2021
Coral Cells Can Spit Out the Symbionts They Don't Want
Some microalgae are symbionts, like dinoflagellates that live in coral. A symbiotic sea anemone is seen in this image by ...
MAY 23, 2021
Cell & Molecular Biology
Predictions in the Fly Brain Use Potentially Universal Methods
MAY 23, 2021
Predictions in the Fly Brain Use Potentially Universal Methods
The brain of the fruit fly may only be the size of a poppy seed, but it seems that it's capable of making prediction ...
Loading Comments...