14.2 - Plant Growth Factors

Question 1

Three factors plants respond too:

Answer 1

Light
water
gravity

Question 2

How do plants respond to light?

Answer 2

Shoots grow towards light because light is needed for photosynthesis

Question 3

How to plants respond to gravity?

Answer 3

Roots are sensitive to gravity and grow in the direction of its pull

Question 4

How do plants respond to water?

Answer 4

Almost all roots grow towards water to absorb it for use in photosynthesis, metabolic processes, and for support

Question 5

What is a plant growth factor?

Answer 5

hormonal like substances as they influence growth and are made by cells across the plant rather than one organ. They are produced in small quantities

Question 6

Example of a plant growth factor and what does it control?

Answer 6

Indoleacetic Acid (IAA), belongs to auxins, controls plant cell elongation

Question 7

How does IAA travel?

Answer 7

In one direction, away from the tips of shoots or roots

Question 8

Role of IAA

Answer 8

Increases plasticity of cell walls (ability to stretch)

Question 9

What does the acid growth hypothesis support?

Answer 9

explains how IAA increases plasticity of cells

Question 10

What happens in the acid growth hypothesis?

Answer 10

active transport of hydrogen into the cell walls spaces causing cell wall to elongate by expansion