"We found that upon decapitation of the plant, there is a rapid increase in sugar delivery to the buds, which promotes bud outgrowth," Babst said. The sugars move about 100 times faster than auxin, a plant hormone previously believed to regulate bud growth. This finding supports the idea that sugarnot auxinis the key signaling molecule for this immediate response to clipping.
"Auxin plays a secondary role later in the process," Babst said.
The Brookhaven experiment further supports the idea that the demand for sugar in intact, actively growing apical shoots limits the availability of this nutrient to the rest of the plant, thus normally keeping lower branch bud growth in check.
"Only a few labs in the world have the capability, using the carbon-11 radioisotope, to do the type of experiment that we did to see rapid changes in carbon allocation immediately following a treatment, such as shoot tip removal," Babst said.
"Ben's work was critical for this study," said Christine Beveridge of the University of Queensland, Australia, who was the lead author on the paper. "His finding that sugars move at 150 cm per hour along the stem is amazing. The technique available in his lab is truly first class and an invaluable resource for plant scientists worldwide."
Relevance to Bioenergy
Brookhaven's role in this research was funded by the U.S. Department of Energy's Office of Science, which has an ongoing interest in furthering understanding of plant functions that have relevance to generating bioenergy.
For example, said Babst, "Branching has a big impact on the display of a plant's leaves to capture sunlight, like arrays of solar panels. Branching can also enhance or hurt the performance of plants growing amongst competitors. And the amount of branching also influences how much biomass a plant ha
|Contact: Karen McNulty Walsh|
DOE/Brookhaven National Laboratory