1. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
EXERCISE VII
PLANT TISSUES
A. MERISTIMATIC TISSUES / MERISTEMS
composed of mitotically dividing cells
responsible for elongation & widening the diameter of plant organs
1. Apical Meristem
found at the tips of stems (shoot apical meristem) & roots (root apical meristem); produce
primary tissues
account for primary growth → elongation of roots & shoots
Root Apical Meristem Shoot Apical Meristem
(RAM) (SAM)
2. Intercalary Meristem
occur between mature tissues
most common in grasses → occur at the bases of the nodes
help regenerate parts removed by grazing herbivores
for rapid elongation of the internodes in monocots
3. Lateral Meristem
cylindrical meristems that form the subapical regions of the roots & shoots of woody plants
produce secondary growth → increases the girth of the plant
secondary growth makes the plant sturdier enabling it to grow taller & intercept light
it includes the vascular cambium & cork cambium (also, phellogen)
vascular cambium → forms the wood (secondary xylem) & secondary phloem
cork cambium (phellogen → forms the periderm which in turn forms a layer of dead,
phellogen)
phellogen
suberized cells that protects the inner tissues of the secondary plant body
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2. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
Intercalary Meristem Lateral Meristem
(found only in monocots) (Vascular cambium & Cork Cambium)
B. PROTECTIVE TISSUES / DERMAL TISSUES
comprise the outermost layer of the plants
1. Epidermis
dermal tissue that covers the primary body of the plant, protecting the underlying tissues
regulates the movement of gases between the plant and the atmosphere
sheet of cutinized cells covering the plants to protect it against rapid water loss &
mechanical injury
modified epidermal cells:
Guard Cells
kidney-shaped in dicots
dumbbell-shaped in monocots
Trichomes
single-celled or multicellular outgrowths of epidermal cells
found in leaves, stems, flowers, & fruits
e.g.: cotton fibers → from the epidermis of cotton seeds
2. Cork
the outermost part of the periderm
secondary tissue produced by the cork cambium
Epidermis with Guard Cells & Trichomes Cork
Stomata
Stomata
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3. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
C. FUNDAMENTAL/ GROUND TISSUES
more variable in function & type
it constitute the mesophyll in leaves & the cortex & pith in stems & roots
1. Parenchyma
isodiametric or polyhedral cells with prominent protoplast & thin walls
common examples are:
Chlorenchyma – contains chloroplasts
Aerenchyma – cells with prominent intercellular spaces
2. Collenchyma
consists of cells with unevenly thickened cell walls
functions for support
3. Sclerenchyma
consists of cells which are devoid of protoplast upon maturity but has thick lignified walls
two types of cells:
Sclerids – short & polygonal
e.g.: stone cells in pears gives it a gritty texture (rough)
Fibers – long and with tapering ends
e.g.: hemp fibers for making ropes
Parenchyma Collenchyma Sclerenchyma
Distinguishing made up of made up of collenchyma made up of fibers (long
Features parenchyma cells → cells → elongated in slender cells typically
usually many sided shape occurring in strands) &
sclerids (variable shape,
shorter than fibers)
Cell Wall primary or secondary; unevenly thickened primary & thick secondary;
may be lignified, primary cell wall only; usually lignified
suberized, or cutinized not lignified
alive at maturity alive at maturity maybe alive or dead at
maturity
Location on Throughout the plant beneath the epidermis in Fibers: usually associated
the Plant Body body young elongating stems with xylem & phloem; in
often seen as a cylinder leaves in monocots;
of tissue or only in sometimes in cortex of
patches in ribs along stems
veins in some leaves Sclerids: throughout the
plant
Function for metabolic processes support in primary plant Fibers → for support
such as respiration & body Sclerids → for protection &
photosynthesis; storage mechanical support
& conduction; wound
healing & regeneration
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4. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
Parenchyma Cells Chollenchyma Cells Sclerenchyma Cells
Sclerenchyma (Fiber Cells) Sclerenchyma (Stone Cells)
D. Vascular / Conducting Tissues
Vascular tissues are complex → i.e. composed of four types of cells
1. Xylem
for transport of water & dissolved minerals absorbed by the roots from the soil
composed of fibers, parenchyma cells, vessels (large), & tracheids (small, devoid of
protoplast)
Vessels & Tracheids
main water-conducting elements
exhibit secondary wall thickenings which can be annular, spiral, scalariform,
reticulate, or pitted
Xylem showing vessel elements & tracheids
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5. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
in longitudinal (left) and transverse (right) sections.
2. Phloem
for transport of food materials from the leaves to all plant parts
in woody stems, phloem tissues constitute the greater bulk of the bark
consists of fibers, parenchyma cells, & sieve tube cells (devoid of protoplast)
Sieve Tube Cells
main food-conducting elements
thick-walled & provided at both ends with perforated sieve plates
companion cells → associated with sieve tube cells
Phloem showing sieve tube members & companion cells
in longitudinal (left) & transverse (right) sections.
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6. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
PLANT ORGANS
Vegetative Plant Organs:
1. Roots
2. Stems
3. Leaves
Reproductive Plant Organs:
1. Flowers
2. Fruits
3. Seeds
A. ROOTS
Root System
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7. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
Monocot Root
Young Eudicot Root
1. Epidermis – uncutinized cells with root hairs (to facilitate absorption)
2. Cortex – multi-layered parenchyma cells:
Endodermis = inner most layer (endodermal cells)
Casparian strip = suberized
Passage cells = for water transport
3. Stele – innermost cylinder
Pericycle – made up of parenchyma cells; gives rise to the vascular cambium &
secondary/lateral roots
Xylem – 3-4 radial rows of thick walled cells alternating with thin phloem cells
Vascular cambium – meristimatic zone between phloem & xylem
Phloem – thin-walled; food conducting cells alternating with xylem rays
Pith – if present, composed of parenchyma cells
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8. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
B. Stems
Morphology
Monocot stem (cross section)
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9. BIO 101 Laboratory
This serves as a supplement in the laboratory.
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C. Leaf
Morphology Venation
Monocot Eudicot
(Parallel) (Netted/Reticulated)
Monocot Eudicot
Simple Leaf
Pinnately Compound Leaf Palmately Compound Leaf
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10. BIO 101 Laboratory
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Leaf Arrangement
Whorled
Alternate Opposite
Monocot:
Eudicot:
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11. BIO 101 Laboratory
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D. Flower
Morphology
Complete Flower – has all 4 parts (sepals, petals, pistil, stamen)
Incomplete – lacks one or more of the 4 parts
Perfect Flower (bisexual) – has both stamens & carpels/ovary
Imperfect Flower (unisexual)– has stamen or carpel but not both
Imperfect flower = Incomplete Flower
Monoecious – male & female reproductive parts in separate flowers (e.g.: corn)
Dioecious – male & female reproductive parts in separate plants (e.g.: papaya)
Inflorescence
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12. BIO 101 Laboratory
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E. Fruit
matured / ripened ovary
holds & protects seeds
Simple Fruit – developed from a single ovary
Aggregate – several ovaries of a flower (sugar apple)
Multiple – several ovaries of several flowers (pineapple)
TERMS:
Pericarp - the fruit wall (derived from the ovary of the pistil) which is composed of the exocarp,
mesocarp and endocarp (the three layers are not always recognizable, ex. dry fruit)
Endocarp - the innermost layer of the pericarp (often hard, stony or papery)
Mesocarp - the middle layer of the pericarp (often fleshy)
Exocarp - the outermost layer of the pericarp (often like a skin or peel). (peach)
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13. BIO 101 Laboratory
This serves as a supplement in the laboratory.
Don’t use this in your lecture class.
Types of Fruits
Fleshy
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14. BIO 101 Laboratory
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Dry Fruits
Dry Dehiscent
Dry Indehiscent
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15. BIO 101 Laboratory
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F. Seed
Albuminous (Endospermic) Seed :
(Non-
Exalbuminous (Non-endospermic) Seed
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