Plant Endocrinology Flashcards
Auxins
Class of plant hormones that coordinate growth and behavioral processes in a plants life cycle and are essential for plant body development. Play a key role in:
- Phototropism
- Geotropism
- Inhibition of lateral buds
Phototropism
A type of growth pattern in which the shoots of plants bend toward light sources. The hormone, Auxin, is responsible for this process and its supply is reduced when light strikes the top of a plant from one side. Thus, the illuminated side of the plant grows more slowly than the shaded side.
Geotropism
A type of growth pattern in which plants grow towards or away from gravity. The hormone, Auxin, is responsible for this form of growth. Two forms of geotropism exist:
- negative geotropism
- positive geotropism
Negative Geotropism
The process by which shoots of plants grow upward and away from the acceleration of gravity.
Positive Geotropism
The process by which the roots of plants grow towards the pull of gravity.
Auxins role in the inhibition of lateral buds
Auxins produced in the terminal bud of a plants growing tip move downward in the shoot and inhibit development of lateral buds. Auxins also initiate the formation of lateral roots and inhibit root elongation.
Gibberellins
Plant hormone that:
- stimulates rapid stem elongation in dwarf plants
- inhibit formation of new roots
- stimulate production of new phloem cells
- terminate dormancy of seeds and buds
Kinins
Plant hormone that:
-promotes cell division
Note: kinetin is enhanced when auxin is present
Ethylene
Plant hormone that:
- stimulates root ripening
- induces senescence or aging
Plant inhibitors
Block cell division and serve an important role in growth regulation. Abscisic acid is on of the most important plant inhibitors.
Anti-auxins
Regulate the activity of auxins
Meristematic Tissue
Undifferentiated cells found in the shoot and roots of the plant where growth can occur. Involved in the production of plant hormones, which are primarily involved in the regulation of growth.
