1. Physiology of Seed Plants

2. Regulating Growth and Development: The Plant Hormones
Auxins
Cytokinins
Ethylene
Abscisic Acid
Gibberellins
Molecular basis of Hormone Action

3. Hormones
Chemical signals that help both plants and animals regulate and coordinate metabolism, growth, and differentiation.
Phytohormones- plant hormones

4. Three basic elements of Hormones
Synthesis of the hormone in one part of the organism
Transport of the hormone to another part (target tissue)
Induction of chemical response

5. Phytohormones Produced in tissues or glands
Very active in small quantities
Pineapple Ananas comosus for example are only 6 micrograms of indoleacetic acid (IAA) a common plant hormone per kg of plant material. (analogous to a needle in 20 metric tons)
Can stimulate or inhibit depends on chemical structure and how it is read by the target tissue

6. Five classes of plant hormones The “Classic Five”
Auxins
Cytokinins
Ethylene
Abscisic acid
Gibberellins

7. Auxins
Charles Darwin and Francis Darwin- The Power of Movement in Plants 1881

17. Additional chemicals used by plants
Brassinosteroids- naturally occuring polyhydroxyl steroids (tissue growth)
Salicylic acid- phenolic compound similar structure to aspirin implicated in defense responses
Jasmonates- class of compounds known as oxylipins plant growth regulation and defense
Polyamines- strongly basic molecules found in all organisms (bacteria, fungi, animal, plants) are essental for growth and development and affects cell division
Systemin- a polypeptide functions as a long distance signal to activate chemical defenses against herbivores.
Nitric oxide (NO) serves as a signal in hormonal defense responses.