Plant Hormone
Auxin
Function
• Promotes stem elongation, adventitious root
initiation, fruit growth
• Inhibits axillary bud outgrowth and leaf
abscission
• Involved in apical dominance and tropisms
Cytokinin
•
•
•
•
•
Ethylene
Gibberellins
Inhibit leaf senescence
Promote cell division and axillary bud outgrowth
Affect root growth
Promotes fruit ripening and leaf abscission
Inhibits stem elongation and gravitropism
• Promote seed germination, stem growth and fruit
development
• Break winter dormancy
• Mobilize nutrient reserves in grass seeds
Abscission = the dropping of leaves, fruits, and flowers
Senescence = aging
Gibberellin
Auxin
Cytokinins
Ethylene
Germination Growth Flowering Fruit
Abscission Seed
to
Development
Dormancy
Maturity
Abscisic
Acid