The functions and the ultimate result
of specific damaged tissue of plant root are given below;
1. ROOT CAP
The tip of the root
is covered by a cap that is shaped like a thimble. The outer cells of
the root cap are continuously being worn away and new cells are added to the
inner portion. As these cells disintegrate they form a strong protective cover.
FUNCTION
- The root cap covers
and protects the delicate growing tip from injury and damage as the
root pushes its way through the soil.
- If
it is damaged then growing tip will be injured
failure in protection will happen
- Elongation of
root is stopped and hence roots remain short.
2. MERISTEMATIC REGION
This region occurs immediately
behind the root cap. The Meristematic region consists of meristematic tissue
and is protected by the root cap. The cells are very active and divide
rapidly to form new cells which differentiate later to form more specialized
root tissues. The cells of this region also replace the cells rubbed-off
from the root cap and provide additional cells for the next
region.
FUNCTION
- This is the
region where the cells divide and where additional cells are provided
for the zone of elongation.
- Damage
in this region will result in failure of cell
division. Hence no increase in root girth and no adding to new cells to
the old root hence when old vascular bundle is blocked there will be no
adding up of the new vascular tissue.
3. REGION OF ELONGATION
The cells formed in
the meristematic region undergo rapid growth in length. This causes the
root to elongate and penetrate deeper into the soil in search for water
and mineral salts. The meristematic and elongation zones are also referred to
as the region of growth.
FUNCTION
- In this region
the cells undergo rapid enlargement,i.e. the cells undergo rapid
growth in length.
- In
case of damage growth of plant root will be
ceased. And root may be unable to perform its function.
4. ROOT-HAIR
FUNCTION
- The main
function of the root hairs is to increase the area of absorption of
the root.
- If
it is damaged then failure in absorption takes
place. There will be entry points of the pathogens like nematodes,
bacteria and fungi to the damaged roots easily
5. THE ZONE OF MATURATION
The mature region is
situated above the root hair region. Here the root becomes thicker
and secondary or lateral roots are developed. The secondary roots in turn rebranch
to form tertiary roots. Each lateral branch has its own cap, root hairs,
meristematic, elongation and mature regions. The roots in this region are
covered by a protective cork layer
FUNCTION
- In this region
the cells undergo differentiation into specialized cells, (e.g.
xylem and phloem).
- It also serves
to anchor the plant.
- In
case of damage failure in anchorage and
differentiation happens.
6. EPIDERMIS
FUNCTIONS
- The epidermis protects
the underlying tissues of the root.
- The epidermal
cells and the root hairs absorb water and dissolved ions.
- In
case of damage failure in absorption and
protection happens
7. CORTEX
FUNCTIONS
- The cortex
allows for the diffusion of water, mineral salts and oxygen from
the root hairs inwards.
- The cortex stores
foods reserve, especially starch.
- The cortex also
serves to transport water and salts from the root hairs to the
center of the root.
- The endodermis,
with the aid of the Casparian strips, facilitates the movement of water
from cortex to xylem.
- If
it is damage then failure in food storage and
diffusion happens.
- No storage of
the food and the pathways of movement of water from epidermis to the
vascular tissue is also stopped hence plant may face wilting.
8. VASCULAR CYLINDER
FUNCTIONS
- Branch or
lateral roots originate in the pericycle.
- The xylem transports
water and dissolved substances from the roots to the stem and leaves.
- The xylem is the
main strengthening tissue of the root.
- The phloem transports
organic substances such as carbohydrates from the leaves to the root.
- If
it is damaged then failure in transportation of
water and food happens.
- Blockage of the
tissue (by bacteria or fungi etc.) will result in Permanent Wilting of the plant.
