Ch 40 - Plant Defense Response

Question 1

Physical Defenses

Answer 1

Abiotic: Axillary buds give plant second chance if they’re uprooted or broken
Biotic: Dermal layer keeps invasive species out

Question 2

Dermal Tissue System

Answer 2

First defense
Wax, cutin and suberin protect from water loss and attack
Bark, thorns, etc

Question 3

Dermal System Weaknesses

Answer 3

Mechanical wounds let microbio in

Parasitic nematodes tear insides apart with teeth, ruin roots

Question 4

Fungal Invasion

Answer 4

1. Windblown spore lands on leaf
2. Spore germinates and forms adhesion pad
3. Hyphae grows thru cell walls and presses against membrane
4. Hyphae differentiate

Question 5

Beneficial Microorganisms

Answer 5

Mycorrhizal fungi
Nitrogen-fixing bacteria
Plant growth promoting rhizobia (PGPR)

Question 6

Toxin Defenses

Answer 6

Produce toxins to hurt herbivores
Plants either:
1. Sequester toxin in membrane bound organelle
2. Produce compound thats non toxic until digested by animal
Allelopathic plants secrete chemicals to block germination of plants nearby
Ricin: lethal bean excretion, inhibits translation

Question 7

Plants with Medicinal Value

Answer 7

Phytoestrogens of soy plants
Taxol of Yew trees fights cancer
Quinine of Cinchona trees, prevents malaria

Question 8

Animals Protecting Plants

Answer 8

Mutualizm
Army ants protect against herbivores
Wasps, caterpillars & leaves