This document discusses the characteristics of meristematic tissues in plants. It defines meristem as undifferentiated, immature cells capable of cell division. There are three main types of meristems - apical, intercalary, and lateral - located in different parts of plants and responsible for primary and secondary growth. Key characteristics of meristem cells include being self-renewing through mitosis, having thin cell walls, a large prominent nucleus, actively dividing to add new cells, and enabling continuous plant growth and development of new organs.
2. What is meristem?
Word "meristem" is coined by Nageli (1858)
• Simply we can say that the cells having the ability
to divide and re-divide
• The group of immature, undifferentiated cells
that has capacity to divide and form new cells
• Meristems in plants are found in apex of stem
root, leaf primordia, vascular cambium, cork
cambium etc.
3.
4. Type Location Function
1-APICAL
MERISTEM
Growing tips of shoot (shoot
apex meristem ) and root
(root apex meristem)
Increases length (height of the
plant)
-PRIMARY GROWTH
2-INTERCALARY
MERISTEM
At base of leaves or
internode
Increase in length of organ like
leaves and internode
3-LATERAL
MERISTEM
(Found in woody
trees )
On sides of stem and root
-TYPES
1-Cork Cambium
(found beneath bark)
2-Vascular Cambium
(found in vascular bundles)
Increase the diameter and girth
- SECONDARY GROWTH
5.
6. PROPERTIES OF MERISTEM
• Self-renewing cells
• lt means that each cell of meristem when
divides into two daughter cells
• 1. one will be the meristematic cell and
• 2. 2nd other head off to become a programmed
or specialized mature cell.
7. • Absence of intercellular spaces
• Intercellular spaces are absent because of
• rapid divisions. Metabolism rate is high
enough to resist any attack of pathogen.
• That's why meristem cells are used for
cloning and vegetative propagation.
8. • CELLS are living.
• All cells are living. Only meristematic
tissues are completely made up of living
cells while other tissues may constitute
both living and dead cells for example
bark of wood.
9. • Cell structure
• Thin cell walls are present.
• Small or no vacuole.
• Large prominent nucleus.
• Cells are oval rounded or polygonal
in shape.
• Isodiametric in nature
10. • Cells have thick cytoplasm.
• Endoplasmic reticulum and plastids
are absent.
• Devoid of reserved food material.
11. • Diploid cells
• Meristematic cells are diploid cells and
perform mitosis.
• As a result of which new cells are
continuously adding.
• Hence credited as the most actively
dividing tissues of the plant.
12. • Cell division
• They are responsible for primary
(elongation) and secondary
(thickness) growth of the plant.
• All new organs and their growth
occur by the division of meristematic
tissue
13. • Growth
• Secondary tissues such as, wood,
cork are also formed due to activity
of meristematic tissue.
