Transcript Exer 4 - BreaktheLight

Exercise 5
Plant Cell Types and Tissues
Tissue – group of cells that perform
a specific function
2 kinds of tissues (state of development):
1. Meristematic tissues/ meristerms
- responsible for the production of new cells
2. Permanent tissues
- perform specific functions
Kinds of meristems based on their
position or location:
1. Apical meristem – responsible for the increase in
length of stems or roots
- at tips or apices of stems and roots
- with very small or no vacuole at all
- very thin-walled and isodiametric
Includes:
a. Protoderm
b. Ground meristem
c.
Procambium
2. Lateral meristem
3. Intercalary meristem – at bases of young
leaves and internodes
- for further lengthening of stems and leaves
far away from the tips of stems
Kinds of Permanent Tissues:
1. Simple permanent tissues
- consist only of one kind of cell
a. Epidermis – outermost tissue of leaves,
stems and roots of all monocots and
herbaceous dicot
- has a layer of cuticle made up of waxy
substance called cutin to prevent excessive
evaporation of water
- uniseriate when young, multiseriate when
b. Parenchyma –
uniformly thin-walled
- Function: for food
storage
- Examples: cassava
pith, tomato fruit
pulp, Spanish flag
petiole
c. Collenchyma – with
unevenly thickened
walls
- function: for
strengthening & support
and sometimes for
storage
- examples: lotus petiole,
celery petiole, coleus
petiole
d. Sclerenchyma – with
heavily thickened walls
because of the presence
of lignin
- function: for
strengthening & support
- Examples: mungbean
seed coat, peanut
pericarp, pineapple leaf
e. Cork – outermost tissue of leaves and roots of woody
dicot plants
- function: for protection
2. Complex Permanent Tissue
1. Phloem – conducts dissolved organic food materials
Sieve tubes
Companion cells
Arranged end to end
Shorter, narrower, vertically
elongated
Denucleated when matured
Nucleated even when matured
2. Xylem – conducts water
a. Tracheids – without perforations
b. Vessel elements – with perforations
Accessory cells – participate in osmotic changes involved
in movements of the guard cells
Closed Stomata
Open Stomata
Exercise 6 Absorption
1.
2.
Tap Root
Fibrous Root
Specialized Roots
Specimen
Camote
Radish
Carrot
Rhizophora
Pandan
Modification & function
Enlarged fleshy root for food
storage
Enlarged fleshy root for food
storage
Enlarged fleshy root for food
storage
Brace roots for support
Prop roots for support
*brace roots – aerial roots arising from the main stem which penetrates the ground
*prop roots – aerial roots arising from the branches which penetrate the ground
Exercise 7 Transport &
Nutrition

Origin of the stem: from the epicotyl and
partly from the hypocotyl of the embryo

Shoot – a stem with leaves

Shoot system – all the stems and leaves of a
plant
General Features of the Stem:
1. Node – where leaves, branches & buds arise
2. Internode – portion between 2 consecutive nodes
3. Leaf sheath
- in some monocotyledons (Poaceae/ Gramineae/
grass family), a distinct petiole is lacking. Instead,
the blade is supported by a flattened structure
called the leaf sheath, which clasps the stem.
4. Petiole – or leaf stalk
- holds the blade upright
5. Leaf scar – mark left on the stem by a fallen
leaf
6. Bundle scar – cut end of vascular bundles
seen within each leaf scar
7. Leaf axil – angle formed by the leaf stalk and
the stem
8. Axillary bud – located at the leaf axil
9. Terminal bud – located at the tip of the stem
10. Bud scale – protective scale that covers the
bud
11. Lenticels – tiny raised pores on dicot stems
for gaseous exchange
Modified Stems:
Plant Specimen
Fern plant, Ginger
Modification
Rhizome for food storage
Gabi
Corm
Potato (Solanum tuberosum)
Tuber for reproduction
with “eyes” = buds
Bermuda Grass
Bougainvillea
Dilang-baka
Vine
Cycas
Runner/Stolon
Thorn for protection
Cladophyll
Tendril
Spines for protection
Exer 7 Leaf
Important Terms:
1. Phyllotaxy – system of leaf arrangement on the
stem:
a. Alternate or spiral – only 1 leaf develops at each
node
b. Opposite – 2 leaves develop opposite each other
at a node
c. Whorled – 3 or more leaves develop equidistantly
around the node

2. Blade or lamina – thin, flattened, green
structure
3. Leaf stalk or petiole – holds the blade
upright; to provide maximum exposure
*sessile – leaf without petiole
4. Stipules – a pair of outgrowths at base of
some dicotyledonous leaves
*exstipulate – without stipules
Petiolule – stalk of each leaflet
 Stipels – outgrowths in pairs found at the
base of petiolule
 Rachis – continuation of the petiole

5. Nature of leaf blade
a.
b.
Simple leaf – blade consists of only 1 piece
Compound leaf – blade is divided into
separate segments called leaflets or pinna
6. Venation – arrangement of vein of
a leaf blade
a.
b.
Netted or reticulate venation – veins branch
profusely and form a network over the
blade; commonly found in dicot leaves
Parallel venation – veins do not form a
network; commonly found in monocot
leaves