A. Taproots – includes a single root that reaches
straight down with many branches off to the side.
B. Fibrous Roots – contain an extensive mass of
similarly sized, usually shallow roots such as
those seen in grasses
C. Adventitious Roots - produce a crown of
roots that may devel0p into an extensive
network , such as that seen in corn, ferns, and
other interesting plants.
Varieties of taproots are
found in dandelions,
pines, and many oaks.
They reach way down
before branching.
Examples of
extensive
shallow root
systems include
grasses, sweet
potatoes, and
many others.
They are major
preventers of
soil erosion.
Adventitious roots form a
variety of root systems, such
as those adapted for
underground growth,
(ferns); aspens,(cloned root
system); even raspberries,
(cuttings for propogation.)
Corn and its prop roots are a
perfect example.
Anchorage – In permeating the soil to look for water,
roots anchor a plant for life.
Storage – Roots store large amounts of energy reserves.
Absorption – Roots absorb large amounts of water and
minerals. Corn absorbs 2 liters a day!
Conduction – Roots transport food and water to and
from the shoot. Some even send CO2 to leaves for
photosynthesis.
A. Protection - The root cap is a strong and powerful
apical meristem that grows downward to pave the
way for the main shoot.
B. Lubrication - Mucigel lubricates and prevents
growth of other plants’ roots nearby.
C. Water absorption - Absorption is carried out by soil
particles clinging to the mucigel.
D. Nutrient absorption - is influenced by carboxyl
groups which increase the uptake of nutrients from
the soil.
Root tip structure and Function
6
1.
2.
3.
4.
5.
6.
Apical Meristem
Root Cap
Zone of Elongation
Dead root cap cells
Procambium
Zone of cell division
1.
Apical Meristem – main growth region of the root
tip.
2.
Root Cap – hard portion that pushes through
obstacles in soil; concrete; etc..
3.
Zone of elongation – where most of the cells
elongate by filling water vacuoles in their cells.
These are typically the longest root cells
4. Dead Root Cap cells – sloughed off after damage
from working so hard.
5. Procambium – develops into the new cambium layer for
transport of water, nutrients and minerals
6. Zone of Cell Division– distinguished by presence
of most root hairs and older, less mitotic cells.
1. Prop Roots aid in anchorage in soft soils and
gathering oxygen in poorly oxygenated soil.
2. Buttress roots are used in the rainforest by very
large trees with poor anchorage.
3. Propogative Roots spread through cuttings or
suckers to form new trees or plants which may
or may not be attached to the original plant.
The largest such example is a Quaking Aspen
in Utah that has 47,ooo trunks and covers 43
hectares!
4. Some root systems rely on fungi called
Mycorrhizae to help the root absorb nutrients
from the soil.
1. Absorption – Takes place in the Zone of
Maturation by the root hairs and mucigel
working in association with the soil.
2. Conduction – Roots contain cambium with
xylem and phloem which conduct minerals,
food, and water for the plant.
3. Propogation – the cutting or spreading of roots
for the purpose of increasing the number of
plant stems or numbers.
1. Roots affect the pH of the soil as they absorb
Nitrogen compounds.
2. The soil area around a root is called the
rhizosphere.
3. As roots die, the organic decay left behind helps to
provide more nutrients for the soil, which in turn
further affects pH.
4. Also, aeration for the soil occurs as roots die,
leaving open spaces behind for oxygen and other gases
to penetrate the soil.
1.
Roots provide food. Early foods such as wheat and
carrots came from wild plants. The wild carrot for
example is Daucus carota.
2. Sugar beets provide the majority of sugar eaten in the
United States.
3. The potato is the most widely eaten root food in the
world.
4.
5.
Sassafras makes a wonderful tea that helped replace
the tea lost from English trade during the American
revolution.
5. Ginseng is widely used throughout the world as a
dietary supplement to help increase stamina and
physical performance.