Meristem

Botany Anatomy

2. Presentation of Plant AnatomyPresentation of Plant Anatomy
Presented to;Presented to;
Mam TaibaMam Taiba
Presented by;Presented by;
Farrukh JamilFarrukh Jamil
Roll no;Roll no;
_001_001

3. Plant Tissues;Plant Tissues;

Groups or masses of the cells that are alike in Groups or masses of the cells that are alike in
region, structure, and function form tissue. region, structure, and function form tissue.
From the study point of view, the tissues may From the study point of view, the tissues may
be grouped into three principal groups;be grouped into three principal groups;

1-Meristems or meristematic tissues.1-Meristems or meristematic tissues.

2-Permanent tissues.2-Permanent tissues.

3-Secretory tissues.3-Secretory tissues.

4. MeristemMeristem

Meristem is a ‘Geek word Meristosis” Meristem is a ‘Geek word Meristosis”
meaning to divide.meaning to divide.

A meristemic tissue consists of a group of A meristemic tissue consists of a group of
cells which remain in a continuous state of cells which remain in a continuous state of
division or they retain their power of division.division or they retain their power of division.

5. Meristem

6. Charectrstics of meristem;Charectrstics of meristem;

Composed of immature cells which are state of Composed of immature cells which are state of
division and growth.division and growth.

Intercellular spaces are absent.Intercellular spaces are absent.

Cells are rounded,oval or polygonal in shape.Cells are rounded,oval or polygonal in shape.

Cells are always living and thin walled.Cells are always living and thin walled.

Each cells has abundant cytoplasm and one or Each cells has abundant cytoplasm and one or
more nuclei.more nuclei.

Nuclei are may quite small or absent.Nuclei are may quite small or absent.

The cells are capable of regular,continuous The cells are capable of regular,continuous
mitotic division.mitotic division.

7. Classification 0f Meristem;Classification 0f Meristem;

The meristematic tissue is classified on the basis of The meristematic tissue is classified on the basis of
origin, location in the plant body and differentiation.origin, location in the plant body and differentiation.

Based on originBased on origin

Based on locationBased on location

Based on differentiationBased on differentiation

8. Based on origin;Based on origin;
Based on origin, meristem can be classified into Based on origin, meristem can be classified into
the following two types:the following two types:
Primary meristemPrimary meristem
Secondary meristemSecondary meristem

9. Primary Meristem;Primary Meristem;

It is the meristem present at right from It is the meristem present at right from
embryonic stageembryonic stage

Active throughout the life of plantActive throughout the life of plant

Responsible for primary growth in the plant Responsible for primary growth in the plant
bodybody

Responsible for primary growth in the plant Responsible for primary growth in the plant
bodybody

It gives rise to primary permanent tissue of the It gives rise to primary permanent tissue of the
plant bodyplant body

Found at the tip of root and shootFound at the tip of root and shoot

10. Example Example

Meristem found at the tip of the stem and root.Meristem found at the tip of the stem and root.

11. Secondary Meristem;Secondary Meristem;

It is the meristem that aears later in the life It is the meristem that aears later in the life
cycle of a plantcycle of a plant

. It is responsible for secondary growth in the . It is responsible for secondary growth in the
plant bodyplant body

. It gives rise to secondary permanent tissues . It gives rise to secondary permanent tissues
such as secondary cortex and secondary such as secondary cortex and secondary
xylem.xylem.

e.g Cork cambium and vascular cambium.e.g Cork cambium and vascular cambium.

12. . Based on Location (or Position) . Based on Location (or Position)
in the Plant Bodyin the Plant Body

Apical meristemApical meristem

Intercalary meristemIntercalary meristem

Lateral meristemLateral meristem

13. Apical Meristem;Apical Meristem;

It is the meristem present at the tip of the root It is the meristem present at the tip of the root
and stem, commonly called as root apex and and stem, commonly called as root apex and
shoot apex respectively.shoot apex respectively.

Such meristems constitute the actively Such meristems constitute the actively
growing regions in the plant body. growing regions in the plant body.

Due to the activity of apical meristem the plant Due to the activity of apical meristem the plant
body keeps increasing in its lengthbody keeps increasing in its length

14. Root and Apical MeristemRoot and Apical Meristem

15. Shoot Apical MeristemShoot Apical Meristem

16. Root Apical MeristemRoot Apical Meristem
1.Root cap
initials
2.Protoderm
3.Ground
meristem
4.Procambium
5.Root cap

17. Inercalary Meristem;Inercalary Meristem;

It is the meristem that occurs between It is the meristem that occurs between
permanent tissuespermanent tissues

. It may also occur at the base of the leaves. It may also occur at the base of the leaves

It is particularly common at the nodal regions.It is particularly common at the nodal regions.

It is also responsible for the formation of It is also responsible for the formation of
branches at the nodal regions.branches at the nodal regions.

The apical and intercalary meristems are The apical and intercalary meristems are
examples of primary meristem.examples of primary meristem.

18. Intercalary MeristemIntercalary Meristem

19. Lateral meristemLateral meristem

The lateral meristems are composed of such The lateral meristems are composed of such
initials which divides in mainly in one initials which divides in mainly in one
plane(periclinally) and increase in the diameter plane(periclinally) and increase in the diameter
of an organ.of an organ.

This is responsible for growth in thickness of This is responsible for growth in thickness of
plant body. plant body.

20. Based on Differentiation;Based on Differentiation;

There are three typesThere are three types

Protoderm (It is the meristem that always Protoderm (It is the meristem that always
differentiates into protective structures like differentiates into protective structures like
epidermis).epidermis).

Ground meristem(It is the meristem that Ground meristem(It is the meristem that
always differentiates into ground tissue always differentiates into ground tissue
components such as cortex, endodermis and components such as cortex, endodermis and
pith).pith).

21. ProcambiumProcambium

It is the meristem that always differentiates It is the meristem that always differentiates
into the into the vascular tissuesvascular tissues like xylem and like xylem and
phloem.phloem.

22. Lateral Meristems – secondary Lateral Meristems – secondary
growth in woody plantsgrowth in woody plants
This stem has two lateral meristems. They are the vascular
cambium and the cork cambium. (This is 1 year)

23. Lateral Meristems – secondary Lateral Meristems – secondary
growth in woody plantsgrowth in woody plants
Basswood – root in cross section
Basswood – stem in cross
section; 1, 2, 3 year old stems

24. THANK YOUTHANK YOU