Roots and Stems

Question 1

Functions of Roots

Answer 1

Anchors plant to ground, keeps plant upright, and absorbs water & nutrients (except carbs - plants make them)

Question 2

Human Uses of Roots

Answer 2

Food (parsnips, turnips, beets, etc.), fed to livestock, used for dyes (ex. beets), medicine (ex. ipecac - vomit medicine), erosion control –> holds upper layers of soil in place

Question 3

Types of Roots - Taproots

Answer 3

Large, thick root which may have branching smaller, lateral roots (many have root hairs - outgrowth of epidermal system) –> all gymnosperms and angiosperm eudicots have (ex. dandelions, carrots, beets)`

Question 4

Types of Roots - Fibrous Root System

Answer 4

Many small roots, each of which may have lateral roots & root hairs (tend to be shallower in ground) –> angiosperm monocots have (ex. wheat, grass, corn)

Question 5

Root Specialization

Answer 5

1. Symbiotic relationship with mycorrhizal fungi or nitrogen-fixing bacteria –> helps absorb water & nutrients
2. “Strangler” fig has seeds deposited on branches of other trees by monkeys, birds, ex. (roots grow downward, wrapping around host tree and killing it)
3. Tuberous Roots: store carbs –> harder to access underground (ex. yams, sweet potatoes)

Question 6

Importance of Stems

Answer 6

• Connects roots to leaves (vascular system)
• Support leaves and reproductive organs (flowers)
• Some store water or carbs
• Some have thorns, etc. to protect from herbivores

Question 7

Human Uses of Stems

Answer 7

• Wood, bamboo
• Food (ex. potatoes, celery, sugar cane, maple syrup, cinnamon)
• Salicylic acid (aspirin) from willow bark
• Anti-cancer drugs (ex. taxol from yew trees)

Question 8

Stem Specializations

Answer 8

1. Tubers: some stems grow underground to store food & water or form a new plant (ex. potatoes)
2. Stolons: stems that grow along the soil instead of upright (ex. spider plants)
3. Vines: stems that take advantage of other objects to raise & support leaves (ex. grape stems)

Question 9

Types of Stems

Answer 9

1. Herbaceous Stems: stems that don’t have wood (ex. asparagus, carrots, grass, mint)
2. Woody Stems: stems that have wood (ex. maple trees, roses, pine trees)