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4. Plant interact with the environment. - Coggle Diagram
4. Plant interact with the environment.
Introduction:
Plants don't have sense organs or nervous systems ( are able to detect stimuli and react to them by making in responses).
Can't move about freely, their responses are slower and sometimes less noticeable than those animals.
Plants receive information from the environment and detect changes.
Most important movements are
tropisms
and
nastic movements
.
Tropisms
Characteristics:
Positive tropism is when the plant grows towards the direction of the stimulus.
Negative tropism is when plant grows away from the stimulus.
Permanent changes in the direction a plant grows.
Can be classified according to the source of the stimuli.
Growth responses to external stimuli.
Types:
Geotropism
Roots grow down towards gravity.
Stems grow upward away from gravity.
Hydrotropism
Roots grow towards moisture in the soil.
Phototropism
Stem grow towards the light.
Roots grow away the light.
Thigmotropism
Stolons, like vines, make contact with an object and twist around it.
Nastic movements
Characteristics:
When stimulus stops, the plant returns to its original position.
Can be classified according to the source of the stimuli.
Temporary responses.
Types:
Chemonasty
Response to chemical substances: chemicals like water.
To prevent water loss, plants close their stomata.
Thermonasty
Response to temperature: associated with variations in temperature.
Tulips open and close in response to temperature changes.
Photonasty
Response to light: movements are usually slow.
Gazanias open during the day and close at night.
Seismonasty
Carnivorous plants close their leaves to catch insects when they land on them.
Response to contact: movement is rapid.
