Gibberellins make the grapes grow farther apart in a cluster (which
increases air flow an decreases rotting) and produces larger grapes, a
trait desired by most shoppers.
In nature, gibberellins in seeds are probably the link between
For example, when water becomes available to grass seed, it causes
the embryo in the seed to release gibberellins, which promote
germination by mobilizing nutrients stored within the seed.
another hormone, abscisic acid.
Abscisic acid inhibits many plant processes
In 1960s, one research group studying bud dormancy and another team
investigating leaf abscission (the dropping of autumn leaves) isolated the
same compound, abscisic acid (ABA).
Aba is no longer thought to play a primary role in either bud dormancy or leaf abscission (for which it
was named), but it is a plant hormone of great importance in other functions.
In contrast to the growth-stimulating – auxin, cytokinins and
gibberellins – ABA slows growth.
growth hormones that often determines the final outcome.is the ratio of ABA to one or more
Seed dormancy is an evolutionary adaptation that ensures that a seel
will germinate only when there are favourable conditions of light,
temperature and moisture.
o What prevents a seed dispersed in autumn from germinating immediately; only to be killed by winter?
What prevents seeds from germinating in the dark, moist interior of fruit?
High levels of ABA in maturing seeds inhibit germination.d during seed maturation.