External and Internal Structure of Leaves

Question 1

§ An organ of a vascular plant;
lateral outgrowth of the stem
§ It is usually green, flat lateral
structure that protrudes from a
plant’s stem to collect sunlight for
photosynthesis, and the site
where transpiration takes place

Answer 1

leaf

Question 2

FUNCTION OF LEAVES

§ The process of producing food, that occurs
mainly in the leaves of most angiosperms.
§ This process essentially involves the
absorption of light mainly by the chlorophyll
pigments and the absorption of carbon
dioxide via the stomatal pores in the leaves.
§ As a result of the cleavage of water
molecule during photosynthesis, oxygen is
generated and released to the atmosphere

Answer 2

Photosynthesis

Question 3

FUNCTION OF LEAVES
§ Plants lose a large volume of water through
the leaves in the form of vapor.
§ The exit of water is through the stomata and
the cuticle, but stomatal transpiration is largely
more dominant than cuticular transpiration.
§ It is estimated that the loss of water via
stomata through the process of transpiration
exceeds 90% of the water absorbed by the
roots

Answer 3

Transpiration

Question 4

FUNCTION OF LEAVES

§ the plant leaves synthesize and
translocate the flower-inducing
hormone called florin to the buds

Answer 4

Floral Induction

Question 5

FUNCTION OF LEAVES

Answer 5

Food Storage
Special Uses

Question 6

a broad, flat part of the leaf

Answer 6

blade, lamina

Question 7

a stemlike part of the leaf that joins the blade to the stem

Answer 7

petiole

Question 8

two small flaps that grow at the base of the petiole of some
plants

Answer 8

stipules

Question 9

a strong, thick vein that
runs through the leaf blade from its
base to its apex; continuation of the
petiole and serves for conduction

Answer 9

midrib

Question 10

thinner, lateral branches of
the midrib; for conduction

Answer 10

veins

Question 11

tiny openings or pores in
plant tissue that allow or gas
exchange

Answer 11

stomata

Question 12

these are two
sausage or dumbbell-shaped cells
that surround the stomata and
function to open and close stomatal
pores

Answer 12

guard cells

Question 13

it is where
photosynthesis takes place

Answer 13

mesophyll

Question 14

the
uppermost mesophyll that
consists of compactly stacked,
barrel-shaped parenchyma cells
that are in two rows; contains
more than 80% of the leaf’s
chloroplast

Answer 14

palisade mesophyll

Question 15

lower region;
consists of loosely arranged
parenchyma cells with abundant air
spaces between them; its cells also
have numerous chloroplast

Answer 15

spongy mesophyll

Question 16

scattered throughout the
mesophyll; consist of xylem
and phloem tissues
surrounded by a jacket of
thicker-walled parenchyma
cells called the bundle
sheath; gives the leaf its
“skeleton”

Answer 16

veins/vascular bundles

Question 17

SPECIALIZED LEAVES

Answer 17

VEGETATIVE REPRODUCTION
AERATION
SUPPORT
PROTECTION
STORAGE
ATTRACTION
ABSORPTION/DIGESTION

Question 18

with platelets or buds that
may grow along the notches,
bases, apices and tips of
blades and petioles.
Ex: Kataka-taka

Answer 18

Vegetative Reproduction

Question 19

with enlarged
petiole for buoyancy.
Ex: Water hyacinth

Answer 19

aeration

Question 20

presence of tendrils, hooks
and supporting leaf bases.
Ex: squash tendrils

Answer 20

support

Question 21

presence of bud scales,
motile leaves, spines, stipules and
bracts.
Ex: cactus, pineapples

Answer 21

protection

Question 22

with succulent leaves that
retain water in their large, thin walled
parenchyma cells.
§ Ex: cactus, aloe vera, bulb of onion

Answer 22

storage

Question 23

with petaloid flower bracts
or brightly variegated leaves of some
plants
Ex: poinsettia, bougainvillea, anthurium

Answer 23

attraction