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Botany is a subject related to the study of plants. This subject got increased importance in the field of science as plant growth and maintenance require more attention after various disturbances created in the natural ecosystem by human beings.
In this article, we shall be learning about important concepts related to Auxin and Gibberellin.
Plant Hormone
Plants contain chemical substances that are responsible for growth, development, reproduction, stress control, and many other related activities. These chemical substances are the plant hormones that have single molecules and exist in very moderate quantities. It is also known as phytohormone, which is an organic substance and not any form of active nutrients. Similar to human and animal hormones, it regulates different activities in the plant cell. These are produced in specific parts of the plants and carried to other parts where it evokes biochemical, psychological, and morphological responses. There are mainly five subclasses identified in phytohormones: auxins, gibberellins, cytokinin, abscisic acid, and ethylene.
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Auxins and Gibberellins
Auxins and Gibberellins are two major classes of the hormone, which are plant growth regulators. The plant growth regulators are the hormones that manage and control all the aspects related to the plant’s growth and development. Both these hormones impact growth within the plant and take care of the development processes like flowering, root initiation, organogenesis, sex expression, etc. The physiological reactions of auxins and gibberellins show various effects.
Auxins Definition
Auxin hormones are produced naturally and synthesized artificially within the plants. This hormone is obtained from the amino acid called tryptophan. The term auxin means to enlarge or grow. These are typically located at the growing apices’ roots, and later it migrates to other parts of the plants to stimulate growth. This hormone has a crucial role to play in the development of the plant.
Gibberellins Definition
Gibberellins are a variety of plant and fungal hormones which are acids by their chemical nature. These are a group of hormones that induces plant growth and development. Being a plant growth regulator, it looks after various processes like stem elongation, germination, flowering, enzyme induction, etc. Gibberellins have a dramatic effect on the growth that determines the height of a plant.
Difference between Auxin and Gibberellin
|
Differences |
Auxins |
Gibberellins |
|
Plant Type |
It is found mainly in higher plants. |
It is found mostly in fungi and some higher plants. |
|
Shoot Growth |
It supports growth in the shoot segments. |
It supports growth in the shoot intact. |
|
Root Growth |
It develops rooting on cutting. |
It has zero effect on rooting. |
|
Leaf Growth |
The effect in the leaf’s growth is negligible. |
The effect in the leaf’s growth is prominent. |
|
Bolting |
It does not encourage any bolting activities. |
It encourages bolting activities in rosette plants. |
|
Apical Dominance |
It leads to apical dominance. |
It doesn’t cause apical dominance. |
|
Structure |
It is a single or double unsaturated structure ring. It contains a side chain. |
It has a tetracyclic gibbane structure. Unsaturation is comparatively less. It doesn’t contain any side chain. |
|
Stem Elongation |
It has dwarf shoots that don’t elongate. |
It had dwarf shoots that usually elongated. |
|
Seed and Bud Dormancy |
It does not promote breaking seed and bud dormancy. |
It promotes seed germination, breaking seed and bud dormancy. |
|
Callus Growth |
It plays a prominent role in callus growth. |
It has no role to play in callus growth. |
|
Root Formation |
It helps in root formation. |
It doesn’t help in root formation. |
|
Transport |
It follows basipetal transport. |
It has both basipetal and acropetal transport. |
|
Hormonal Effects |
It has a feminizing hormonal effect. |
It has a masculine hormonal effect. |
|
Functions |
Its main functions are axial elongation, cell division, cell differentiation, cellular expansion, lateral expansion, and isodiametric expansion in plants. |
Its main functions are stem elongation, seed germination, flowering, sex expression, dormancy, fruit senescence, and enzyme induction. |
Difference between Auxin and Cytokinin
|
Difference |
Auxin |
Cytokinin |
|
Primary Role |
It is mainly responsible for cell elongation. |
It is mainly responsible for cell differentiation and cell division. |
|
Production |
It is for |
It is formed in the root and later moves upward in the xylem sap. |
|
Root Branching (Lateral Root) |
It promotes root branching. |
It inhibits root branching. |
|
Apical Dominance |
It maintains apical dominance. |
It has no role to play in apical dominance. |
|
Growth of Lateral Buds |
It prohibits the growth of lateral buds. |
It promotes the growth of lateral buds. |
|
Other Functions |
Its main functions are axial elongation, secondary root growth, apical dominance, and fruit development in plants. |
Its main functions are lateral bud development, cell division, and cell development in plants. |
Did you Know?
The plant hormone auxin can exist naturally, or it can also be processed synthetically. The naturally occurring auxins are indole ethanol, indole acetic acid, and indole acetaldehyde.
Synthetic auxins are sometimes used as growth inhibitors and are treated as a herbicide. It includes 2,4-dichloro phenoxy acetic acid indole butyric acid and naphthalene acetic acid.