90% Agricultural Grade GA powder,Gibberellin hot in Italy CAS
|Melting point||227 °C|
Gibberellins (GAs) are plant hormones that regulate growth and
influence various developmental processes, including stem
elongation, germination, dormancy, flowering, sex expression,
enzyme induction, and leaf and fruit senescence.
All known gibberellins are diterpenoid acids that are synthesized
by the terpenoid pathway in plastids and then modified in the
endoplasmic reticulum and cytosol until they reach their
biologically-active form. All gibberellins are derived via the
ent-gibberellane skeleton, but are synthesised via ent-kaurene. The
gibberellins are named GA1 through GAn in order of discovery.
Gibberellic acid, which was the first gibberellin to be
structurally characterized, is GA3.
GA has a number of effects on plant growth, but the most dramatic
is its effect on stem growth. When applied in low concentrations to
a bush or "dwarf" bean, the stem begins to grow rapidly. The length
of the internodes becomes so great that the plant becomes
indistinguishable from climbing or "pole" beans. GA seems to
overcome the genetic limitations in many dwarf varieties.
Gibberellins are involved in the natural process of breaking
dormancy and other aspects of germination. Before the
photosynthetic apparatus develops sufficiently in the early stages
of germination, the stored energy reserves of starch nourish the
seedling. Usually in germination, the breakdown of starch to
glucose in the endosperm begins shortly after the seed is exposed
to water. Gibberellins in the seed embryo are believed to signal
starch hydrolysis through inducing the synthesis of the enzyme
α-amylase in the aleurone cells.
In the model for gibberellin-induced production of α-amylase, it is
demonstrated that gibberellins (denoted by GA) produced in the
scutellum diffuse to the aleurone cells, where they stimulate the
secretion α-amylase. α-Amylase then hydrolyses starch, which is
abundant in many seeds, into glucose that can be used in cellular
respiration to produce energy for the seed embryo. Studies of this
process have indicated gibberellins cause higher levels of
transcription of the gene coding for the α-amylase enzyme, to
stimulate the synthesis of α-amylase.
Gibberellins are produced in greater mass when the plant is exposed
to cold temperatures. They stimulate cell elongation, breaking and
budding, seedless fruits, and seed germination. They do the last by
breaking the seed’s dormancy and acting as a chemical messenger.
Its hormone binds to a receptor, and Ca2+ activates the protein
calmodulin, and the complex binds to DNA, producing an enzyme to
stimulate growth in the embryo.
A major effect of gibberellins is the degradation of DELLA
proteins, the absence of which then allows phytochrome interacting
factors to bind to gene promoters and regulate gene
expression.Gibberellins are thought to cause DELLAs to become
polyubiquitinated and, thus, destroyed by the 26S proteasome