Chemical Coordination in plants Flashcards Preview

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Flashcards in Chemical Coordination in plants Deck (13)
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1
Q

What is tropism?

A

The growth response of a plant to a directional stimuli

2
Q

What are examples of directional stimuli?

A

Light and gravity as they act in a particular direction

3
Q

What is growth towards stimulus?

A

Positive tropism

4
Q

What is growth away from stimulus?

A

Negative tropism

5
Q

What is light in one direction called?

A

Uni-directional

6
Q

What is light that shines on the plant evenly from every direction called?

A

Uniform light

7
Q

What is the result of phototropism? (light)

A
  • Shoots: positive as the shoots grow towards the light source
  • Roots: negative, most roots don’t respond but if they do they grow away from the light source
8
Q

What is the result of geotropism (gravity)

A
  • Shoots: negative as the shoots grow away from the direction of gravity
  • Roots: positive as the roots grow towards the direction of gravity
9
Q

What is the result of hydrotropism (water)

A
  • Shoots: none

- Roots: positive, some species may grow towards water however only a few

10
Q

What are auxins?

A

Plant growth hormones

11
Q

Describe the response to light

A
  1. Auxins are released from the tip of the plant
  2. They travel along the part of the plant which is NOT exposed to the sun/light
  3. They initiate growth on that side causing the plant to bend towards the light
12
Q

Describe what happens with the auxins in geotropism?

A
  • Auxins accumulate on the lower side of the shoot and STIMULATE growth, causing the shoot to bend upwards
  • Auxins accumulate on the lower side of the root INHIBITING growth and causing the root to bend downwards
  • The receptors in the root and shoots interpret the auxins differently which causes them to grow in different directions
13
Q

Do plants respond to stimuli?

A

Yes