science 1.3 Flashcards
(19 cards)
Tropism is a directional response to
plants to stimuli such as light , water , gravity and to touch coming from a certain direction
Positive tropism
is where the part of the plant which grows towards the stimulus positively
Negative tropism
is where the part of the plan that grows away from the stimulus
What is Phototropism
is the response of plants towards light.
Example of positive phototropism
is when the shoot of the plant grows towards the direction of light
What does positive phototropism ensure?
It ensures that the shoots and leaves of the plant obtain enough sunlight to make food through photosynthesis
What is Hydrotropism
is the response of plants towards water
Example of positive hydrotropism
when the roots of the plant grow towards the direction of water
What does positive hydrotropism ensure?
- It ensures the roots of the plant to obtain water to carry out photosynthesis
- absorbs dissolved mineral salts
What is geotropism
The response of plants towards gravity
Example of positive geotropism
Roots of the plans grow downward towards gravity
what does positive geotropism ensure ?
to grow deep into the ground to grip and stabilise the position of the plant
Example of negative geotropism
The shoot of the plan grow upwards in the opposite direction of gravity.
What does negative geotropism ensure
It allows the shoots and leaves of the plants to grow upwards to obtain sunlight.
What is thigmotropism
groth of plant responding
to touch.
Example of positive thigmotropism
Tendrills or twining stems show positive because they cling onto whatever objects or other plants they come in contact with
This ensures positive thigmotropism
to grow upwards to obtain sunlight and grip onto objects to obtain support.
Example of negative thigmotropism
The root avoid objects that block their search for water
Nastic movement is the response
towards stimulus such as touch
