ITERDUCTION:-
Gibberellin
are second most important growth hormones, found in plants.
It
was discovered by Kurosawa (1926).
It
was 1st extracted from the ascomycetous fungus Gibberella Fugikurui.
It
is the causul organism of “Foalish” seeding of rice or bakanae disease of rice
from the fungus.
Macmillan
isolated gibberllin from the seed of Phaseolus chigher plants.
CHARACTERISTIS:-
Induction
of flowing.
Breaking
of dormancy.
Prevention
of genetic dwarfism.
Increase
of amylase activity.
Substrate
for chilling effect.
DISTRIBUTION:-
All
higher plants process attests one Gibberellins.
A
single plant organ can have more than one Gibberellins,There are sofar 70
gibberellins have been discovered (GA1, GA2, GA70).
Gibberllin
one in highest in seats and young leaves
(A)
Apical Bud.
(B)
Root Tip
(C)
See
CHEMICAL STRUCTER:-
Gibberellins are cyclic diterpenes.
They have molecular formula like C19+246 (GA1) C19H2606 (GA2).
The presence of hydoxyle group and
carboxyle group made them esteritied compound.
Diagram
PHYSIOLOGICAL ROLE:-
(A)
General Growth:-
It regulates growth in Sub-epical
meristem, they cause growth by cell division & elongation.
(B)
Bolting:-
Gibberellin induce stem elongation in
plants with show rosette habit , As result the internides become, 6 to 8 fit
tail, This phenomena is called bolting.
Exmple:- Cabbage, Sugare, beet
[C] Dormanvy Eagles
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