Factors that Affect Plant Growth

Internal Factors

Internal Factors

• Influence growth • Are found within the organism

Remember?• Human growth can be affected by internal

factors like human growth hormone.• What is an internal factor that you think might

affect plant growth?

Plant Hormones

• Auxins• Cytokinins• Gibberellins• Abscisic Acid (ABA)• Ethene

Auxins

Phototropism

Cytokinins

Gibberellins

• Similar to auxins, but the mechanisms of action are not fully understood by researchers!

Abscisic Acid (ABA)

Ethene (Ethylene)

• Effect of ethylene gas on fruit ripening• Tomato ripening experiment

Review: Internal Factors

• Auxins• Cytokinins• Gibberellins• Abscisic Acid (ABA)• Ethene