Chapter 5 : Roots Flashcards
1
Q
Function of Roots
A
- Anchor plant
- Absorb Water & minerals
- Store food
2
Q
Types of Roots
A
- Fibrous roots
- Tap roots
- especially shallow roots examples: cactus and Sitka spruce.
- Especially deep roots examples: alfalfa, field bindweed, tamarisk, and mesquite bush
3
Q
How do roots develop for taproots?
A
- Develop from the radicle in seed
- May have branch roots
- Dicots
4
Q
Hoe do fibrous roots develop?
A
- Narrow
- Adventitious
- From lower stem
- develops from shoot tissue
- Monocots
5
Q
Examples of adventitious roots from shoot tissue
A
- Banyan
- Maple tree grows adventitious roots when branches touch the water
6
Q
What are the structures of a primary root and origin of secondary growth?
A
Apical Meristem
Root cap
Zone of Elongation
Zone of Maturation
7
Q
What is the Apical Meristem?
A
- region of active cell division / growth
- cell division 12-36 hours
- behind the root cap
- Cells are parenchyma cells
8
Q
What are the parts of the Apical Meristem?
A
- Protoderm - outer surface
- Ground Meristem - gives rise to tissue in the cortex of the root
- Procambium - forms a cylinder in the center. Gives rice to the vascular tissue (primary xylem and phloum)
- Pith - present in Monocots. Center of the root. Produced by the ground meristem. Softer tissue
9
Q
What is the root cap?
A
- Thimble-shaped tip
- Has dictiosomes filled with some and release the slime so the root can go through.
- mucus encourages bacteria growth
- Slough off
- Gravitropism - is you peel the root cap off it will grow in random directions. Root cap has gravitropism
10
Q
What is the Zone of Elongation?
A
- Cells elongate or widen
- Cells grow because the vacuole grows
- Cells behind the zone is no longer being elongated
11
Q
What is the Zone of Maturation
A
- They grow root hairs that are all part of one cell
- root hairs like a few days or weeks
- has cortex cells that are parenchyma cells
- Has an endodermis that is a continuous one layer of cells. (Inner Boundary)
- The red stain is called the casparian strips which creates a wall
- The casparian strips are made from suberin
- The Vascular Cylinder or (Stele)
12
Q
What is the Vascular Cylinder or STELE?
A
- Primary Xylem in the center in an x configuration
- Primary Phloem - groups of cells between the arms. Older phloem sluffs off.
- Pericycle - single row of cells inside of the endodermis. Meristem tissue that helps form side roots. Starts secondary growth. Cells on inside becomes xylem and outside becomes Phloem
13
Q
Food storage roots
A
- beets
- potatoes
14
Q
Water storage roots:
A
- Manroot (wild cucumber)
15
Q
Propagative roots:
A
- adventitious root
- make more roots
- lilac suckers
16
Q
Pneumatophore roots:
A
Black mangrove
- nob that shoots up with aerenchyma
17
Q
Arial Roots:
A
- English Ivy
- Banyan Tree
adventitious roots
18
Q
Contractile Roots
A
- Lilies have roots that plant themselves
19
Q
Buttress roots:
A
- Tropical fig tree
- Helps stabilize the tree
20
Q
Parasitic roots:
A
- Parasitic root that penetrates the stem and gets nutrients
- Dodder
- Pine drops
- Mistletoe (Parasitic)
Indian Pipe saprophytic (not parasitic)
21
Q
Root nodules:
A
- Bacteria attach to the root hairs and penetrate to the cortex.
- The cortex grows like a tumor.
- The tumor has bacteria and consumes the sugar the plant provides and the fertilizes the plant.
- root nodules on bur clover
- used to introduce nitrogen back into the soil
22
Q
Phytochromes in roots:
A
- Phytochromes help measure day length for seasonality. (In leaves)
- Helps detect light?
- Taroots acts like a fiber optic cable that channels light down to the phytochromes.
23
Q
Human uses of roots:
A
- Food - Beets, potatoes, carrots
- Spices - ginger, sassafrass, Tumeric
- Alcohol - potatoes
- Drugs - Tobacco, nicotine, fish poison (Rotenone)
