Download Gibberellins

6/5/2014
What is it?
GIBBERELLINS
Gibberellin is a plant hormone
that regulates the growth in
plants.
●
It increase the size of plant more than
its normal
Also the chemical secreted that causes
elongation
● Has the ability to break dormancy in
seeds and delay aging in flowers and
fruits
Structure
● Are diterpenoid acids derived from
tetracyclic diterpenoids know as
Kaurene.
● The basic carbon skeleton is Gibbane
ring
● GA produced in the plastids and
eventually transferred to the
endoplasmic reticulum to me modified
and used.
●
By Dilibe, Amy T. and Rebecca
What is it?
Scientist Ewiti Kurosawa
What is it?
●
discovered that a fungal plant pathogen
Gibberella fujikuroi caused this “foolish
seedling disease” (bakanae).
● by 1930, japanese scientist discovered
that the fungus caused hyper
elongation of the of rice stems by
secreting a chemical.
Gibberella fujikuroi
● a fungal plant pathogen.
● It caused the Bakanae disease in rice
seedling, by overloading them with the
phytohormone gibberellin.
● became additional byproduct.
● the metabolism of which produces a
surplus of gibberellic acid
1950’s and beyond
●
●
the name was given then to gibberellin
because of the fungi gibberellin
more than 100 different types of
gibberellin were discovered.
Gibberellin location
What is it?
Where are they found?
● Mostly found in plant roots and the
young leaves.
● Are synthesized in the root and stem
apical meristem, young leave and the
seed embryo.
● Canopy - upper layer or habitat zone
Primarily synthesized at
site of action:
● Actively growing and elongating
areas
o high expression:
● young leaf, stem,
and flower
o lower expression:
● roots
(root tips show high expression,
but overall root is low)
Figure: expression of gibberellin (GA)-related
genes in various plant organs
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Gibberellin location
Gibberellin location
●
● young seedlings
Germinating seeds
o
high expression:
●
embryo (red arrows)
o
Figure: stained for detection of Gibberellin
gene expression, arrows indicate apical
meristem
low expression:
●
aleurone cells (red
arrowheads)
o based on expression
patterns, aleurone
cells respond to signals
but do not produce
gibberellins
Function?
Function?
Known for stem elongation
Best known for increased
fruit growth.
Normal
Gibberellin induced
(cell elongation and cell division)
● most notable in plants that are deficient in
gibberellin. Such as modified dwarf plants.
● often used in agriculture.
● some plants require both
gibberellin AND auxin for fruit
production.
…...
…..
Funtion?
Function?
Known for seed
germination.
…..
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Function?
Depending on the type of gibberellin hormone, it
is also known for:
● Rapid growth and flowering -- “bolting”
● interrupting seed dormancy in seeds that need
light/stratification for germination
● Induce “maleness” in dioecious flowers
● Induce seedless fruiting
● Postpone death in some leaves and citrus fruit
Bibliography
Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2011). Campbell Biology (9th ed.).
Boston: Benjamin Cummings.
Kaneko, M., Itoh, H., Inukai, Y., Sakamoto, T., Ueguchi-Tanaka, M., Ashikari, M. and Matsuoka, M. (2003), Where
do gibberellin biosynthesis and gibberellin signaling occur in rice plants?. The Plant Journal, 35: 104–115. doi:
10.1046/j.1365-313X.2003.01780.x
Sakai, Miho, Tomoaki Sakamoto, Tomino Saito, Makoto Matsuoko, Hiroshi Tanaka, and Masatomo Kobayashi. "Expression of Novel Rice
Gibberellin 2-oxidase Gene Is under Homeostatic." SHORT COMMUNICATION(2003): 161-64. ProQuest. Web. Apr.-May 2014.
<http://search.proquest.com.ez.sccd.ctc.edu:3048/docview/734595539/43E4D613DF174B2DPQ/3?accountid=36118>.
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