Topic 3.12: Coordination in Plants and Responses to Stimuli

These flashcards cover key concepts related to plant growth responses, the role of auxins, and the understanding of gravitropism and phototropism.

What are plant growth substances?

Chemicals that affect the activities of particular cells and organs in plants.

What is gravitropism?

A response in which parts of a plant grow towards or away from gravity.

What is phototropism?

A response in which parts of a plant grow towards or away from light.

How do auxins affect plant growth?

Auxins stimulate differential growth by causing one side of the plant to grow faster than the other.

What is positive tropism?

A growth response towards a stimulus.

What is negative tropism?

A growth response away from a stimulus.

What is the role of auxins in phototropism?

Auxins accumulate on the shaded side of a plant, causing those cells to elongate more and bend towards the light.

How do roots respond to gravity?

Roots exhibit positive gravitropism, growing towards the source of gravity.

How do shoots respond to gravity?

Shoots exhibit negative gravitropism, growing away from the source of gravity.

What effect do synthetic plant growth substances have when used as weedkillers?

They cause rapid growth that can lead to the death of weeds by disrupting their growth processes.

What are plant growth substances?

Chemicals that affect the activities of particular cells and organs in plants.

What is gravitropism?

A response in which parts of a plant grow towards or away from gravity.

What is phototropism?

A response in which parts of a plant grow towards or away from light.

How do auxins affect plant growth?

Auxins stimulate differential growth by causing one side of the plant to grow faster than the other.

What is positive tropism?

A growth response towards a stimulus.

What is negative tropism?

A growth response away from a stimulus.

What is the role of auxins in phototropism?

Auxins accumulate on the shaded side of a plant, causing those cells to elongate more and bend towards the light.

How do roots respond to gravity?

Roots exhibit positive gravitropism, growing towards the source of gravity.

How do shoots respond to gravity?

Shoots exhibit negative gravitropism, growing away from the source of gravity.

What effect do synthetic plant growth substances have when used as weedkillers?

They cause rapid growth that can lead to the death of weeds by disrupting their growth processes.

What is the function of gibberellins?

Gibberellins primarily promote stem elongation, seed germination, and flowering.

What is the function of cytokinins?

Cytokinins stimulate cell division and differentiation, particularly in roots and shoots.

What is the function of abscisic acid (ABA)?

Abscisic acid (ABA) primarily inhibits growth, promotes dormancy in seeds and buds, and helps plants respond to stress, such as closing stomata during water shortage.

What is the function of ethene (ethylene)?

Ethene (ethylene) promotes fruit ripening, senescence (aging), and abscission (shedding of leaves and fruits).