3. Overview
■ A. Plant tissues: meristematic and permanent
■
‣B. Meristematic
‣ a. epical,
‣ b. vascular cambium
‣ c. cork cambium
■
‣C. Permanent tissues
‣ a. parenchyma,
‣ b. collenchyma
‣ c. schlerenchyma
‣ d. chlorenchyma
■
‣D. Complex permanent tissues
‣ a. vascular,
‣ b. dermal
‣ c. ground tissues
■
‣E.Transpiration and capillary action.
■
4. Meristematic and permanent tissues
■ A meristem is the tissue in most plants containing undifferentiated cells
(meristematic cells), found in zones of the plant where growth can take place.
Meristematic cells give rise to various organs of the plant and keep the plant growing.
■ Permanent tissues is the plant tissue that has completed its growth and
differentiation and is usually incapable of meristematic activity.
5. Function
■ Meristems are responsible for plant growth, regions where cells continuously divide.
■ Meristems are divided into apical, intercalary and lateral meristem.
■ Apical and intercalary meristems are responsible for growth in length (primary
growth), while lateral meristem is responsible for growth in diameter (secondary
growth)
Meristematic tissues:
6. Apical and Intercalary Meristem
■ Apical meristem is responsible for growth in length of most plants.
■ It’s located at the tips of roots and stems of plants
■ Some monocots (plants whose seeds contain one cotyledon) grow in length via
intercalary meristem.
■ It’s located at the base of the stem of monocots, and appears as nodes.
■ It helps grass grow quickly after mowing.
7. Lateral Meristem
■ Gymnosperms (plants whose seeds aren’t protected by an ovary) and most dicots
have lateral meristem
■ Lateral meristem increases the diameter of the plant’s stem and roots
■ Lateral meristem has two types: vascular cambium and cork cambium
■ Vascular cambium is located between xylem and phloem. It produces more vascular
tissue.
■ Cork cambium is located outside the phloem, and it produces cork.
■ Cork cells are dead cells that replace epidermis to provide protection and prevent
water loss
8. Permanent tissues:
These tissues derived from the meristematic tissues but their cells have lost the power of
division & have attained their definite forms. Permanent tissues are classified into simple &
complex tissues.
Permanent tissues are composed of cells which are structurally & functionally similar.
11. Parenchyma
Characteristic:
cells remain alive at maturity
thin-walled cells
isodiametric shape
intercellular spaces
widespread occurrence
in the plant body
(leaves, root, stem)
12. Collenchyma
Characteristic:
cells remain alive at maturity
cell walls are thickened
intercellular spaces absent
or very small
Found in the peripheral
regions of stems and leaves
13. Sclerenchyma
■ Characteristic:
Mature sclerenchyma cells are dead
Cells have thick secondary walls
Found in shells and the outer hard coat of
many seeds
15. Chlorenchymaand aerenchyma
■ In leaves, they form the mesophyll and are responsible for
photosynthesis and the exchange of gases, parenchyma cells in the
mesophyll of leaves are specialized parenchyma cells
called chlorenchyma cells (parenchyma cells with chloroplasts)
17. Xylem
Nature-xylem is a vascular and composed of cells of four different types:
tracheids and vessels element (bounded by thick lignified. Vessels are very long tube-like
structures formed by a row of cells placed end to end.They conduct water).
Functions-
i. The main function of xylem is to carry water & minerals salts upward from the root to
different parts of shoots.
ii. Since walls of tracheids, vessels of xylem are lignified, they give mechanical strength to the
plant body.
18. Phloem
Nature-Phloem is composed of following two types : 1.sieve
tubes;2.companion cells;
Functions-phloem transport photosynthetically prepared food materials from
the leaves to the storage organs & later from storage organs to the growing
regions of the plant body.
25. Transpiration and capillary action:
Transpiration pulls water up a stem:
•the driving force of this process starts at the top of the shoot system
•transpiration occurs, loss of water lowers water potential between the cellulose fibers of the cell walls, and water
quickly is replaced by capillary movement of water from neighboring cell walls, that also pull the water from
other walls until the water is replaced by water from a xylem veinlet.
•as water is pulled out of xylem, the cohesion of water molecules pulls on the water in the xylem column like
pulling of a rope, all the way to root cells which replace the water by absorbing it from the soil
26. Capillary action
■ Capillary action is part of the reason that water
rises in a plant stem and moves throughout the
plant. The water enters the plant’s roots and moves
to other parts of the plant through tiny tube-like
structures called xylem. Xylem are part of the
plants transpiration system, through which
nutrients, including water, are transported
throughout the plant.
27.
28.
29. 1)The elongation of root and stem forms
what is known as the......
A) initial plant
B) protoplant
C) primary plant body
D) secondary growth
30. 2) Internode elongation in corn results from
the growth of....
A) intercalary meristem
B) protoderm
C) procambium
D) cork cambium
31. 3)The outward cell division of the root apical
meristem produces the....
A) root hairs
B) xylem
C) branch roots
D) root cap
E) pith parenchyma
32. 4)Which of the following is not a basic plant
type?
A) pith
B) ground tissue
C) epidermis
D) vascular tissue
E) meristems
33. 5) Gas exchange through the bark occurs
through…..
A) stomata
B) pits
C) lenticles
D) spiracles
E) micropyles
34. 6) Mature sclerenchyma cells are……..
A) suberized and contain no living
protoplasts
B) thin walled and often contain chloroplasts
C) lignified and contain living protoplasts
D) suberized and contain living protoplasts
E) lignified and contain no living protoplast
