PLANTS RESPONSES TO MECHANICAL STIMULI Flashcards
What is Thigmomorphogenesis in plants?
Thigmomorphogenesis is the phenomenon where plants change their growth and development in response to mechanical stimuli like touch or wind. It often results in changes like increased stem thickness, reduced elongation, and increased branching, helping plants adapt to environmental stresses such as wind or animal movement.
How does Thigmomorphogenesis happen in plants?
When plants experience mechanical stimuli (touch or wind), they activate cellular mechanosensors, which trigger biochemical signals. This leads to changes in gene expression and hormone activity, altering the plant’s growth and development.
What is Thigmotropism in plants?
Thigmotropism is the response of a plant to mechanical stimuli like touch. It causes the plant to grow toward or away from the stimulus, influenced by hormones like Auxin and Ethylene. This is commonly seen in vines, ivy plants, and plants with tendrils.
How does Thigmotropism occur in plants?
Thigmotropism occurs when plants alter their growth direction due to touch or mechanical stimuli. The redistribution of growth hormones like Auxin and Ethylene causes the plant to bend toward or away from the stimulus.
plant hormones that regulate growth by promoting cell division, differentiation, and elongation.
Auxin
a hormone that regulates various stages of plant life, including flower opening, fruit ripening, and leaf shedding. It plays a key role in thigmotropism, particularly in plants like vines and those with tendrils.
Ethylene
a non-directional plant movement in response to touch or vibration
Thigmonasty
An example of thigmonasty
Mimosa pudica (makahiya)
How does Thigmonasty occur in plants like Mimosa pudica?
In thigmonasty, the plant’s leaves change shape in response to touch. For example, in Mimosa pudica, the leaves fold when touched due to changes in turgor pressure in the pulvinus, causing cells to shrink and close the leaves.
What happens to Mimosa pudica when its leaves are touched?
The leaves of Mimosa pudica close when touched, a response called nastic movement. This is due to changes in turgor pressure in the pulvinus at the base of the leaflets, which causes the cells to shrink and the leaves to fold.
What is the Greek origin of the word Thigmomorphogenesis?
Thigma = touch
Morphe = form or shape
Genesis = origin or generation
Can you name some plants that exhibit Thigmomorphogenesis?
Pea plant
Bean plant
Tomato plant
What role do mechanosensors play in thigmomorphogenesis?
Mechanosensors in plant cells detect mechanical stimuli like touch or wind. These sensors trigger biochemical signals that lead to changes in gene expression and hormone activity, resulting in altered plant growth.
How does Thigmotropism differ from Thigmomorphogenesis?
Thigmotropism is a directional response to touch or mechanical stimuli, where the plant grows toward or away from the stimulus.
Thigmomorphogenesis, on the other hand, involves broader changes in growth and development, such as increased stem thickness and reduced elongation, in response to mechanical stress.
Can you give an example of Thigmotropism in plants?
Vines, such as those in the ivy plant, exhibit thigmotropism. When they encounter a surface, they tend to grow toward it, curling around it as they seek support.
What is nastic movement in plants?
Nastic movement refers to non-directional movements of plants in response to stimuli like touch, light, or temperature. These movements are not dependent on the direction of the stimulus, such as the opening and closing of flowers or the closing of leaves in Mimosa pudica.
