A University of Queensland (UQ) study has overturned the long-held belief
that plant hormones control plant growth, and shown instead that this
process starts with sugar. Led by Prof. Christine Beveridge of UQ's School
of Biological Sciences, the research team found that shoot growth occurs
when a high concentration of simple sugar (table sugar) - produced by the
plant through photosynthesis - is available.

Their findings overturn the previous belief that plant hormone auxin
regulates shoot branching. Beveridge and her team showed that shoot
branching can begin up to 24 hours before auxin levels change, so it cannot
be responsible for initiating this process. According to Beveridge, plants
have a 'goliath' main shoot, which hoards the sugars to promote its growth.
When the main shoot is damaged or removed, sugars are quickly redistributed
to start the growth of new shoots.

[www.uq.edu.au]