groundbreaker
10 facts on...
GIBBERELLINS
THE GIBBERELLINS are plant hormones that, among other
things, are involved in stem elongation, seed germination, early
development, and flower production.
THERE ARE 126 known natural and synthetic gibberellins
found in not only plants, but also in fungi and bacteria.
Not just a fun word
to say, gibberellins
are crucial in the
natural process of
breaking dormancy
and other aspects of
germination. Philip
McIntosh provides
some insight
into the world of
gibberellins.
GIBBERELLIC ACID (GA or GA3), the prototypical
gibberellin, is the only hormone named after a fungus.
RESEARCHERS IN pre-World War II Japan discovered that the rice pathogen
Gibberella fugikuroi produced a substance causing “foolish seedling disease” in
young plants. This substance turned out to be gibberellic acid.
IF GA is applied to a plant, it generally results in rapid
stem elongation with increased internodal distance.
DWARFISM IN a plant is often, but not always, caused
by a genetic defect in the pathway for GA production.
THE DWARF-TALL trait in pea plants that Gregor Mendel studied to unravel
the basic laws of genetics results from either a defective or properly functioning
gene coding for a protein required for the synthesis of GA.
GA IS an “anti-inhibitor.” It binds to other molecules inside the cell
to prevent them from inhibiting the activation of specific genes.
This allows the gene to be “turned on” to produce its product.
GA IS used commercially in some countries to control
plant development. For example, to delay fruit ripening.
by Philip
McIntosh
162
groundbreakers
SINCE THE activity of GA is quite powerful, the amount
found in plants is relatively low. However, some studies
indicate that concentrated GA is a carcinogen.