Earth and Life Science- How Plants Survive

The plant body is a
hierarchy of structural levels
just like the multicellular
animals, the plant body is
composed of an organ that
is made up of tissues that
is composed of group of
cells.

2 GROUPS OF PLANTS:
♠ MONOCOT
♠ DICOT

♠ MONOCOT
♣ Has only one (1) cotyledon.
♣ Its veins are usually PARALLEL.
♣ Its vascular bundles are complexly
arranged.
♣ It has fibrous root system.
♣ Its floral parts usually in multiples
of three (3).

♠ DICOT
♣Have two (2) cotyledons.
♣Its veins are usually NET-LIKE
♣Its vascular bundles are arranged in
rings.
♣Taproot is usually present.
♣Its floral parts are usually in
multiples of five (5)
or four (4).

ROOTS
The root is an essential in a
plant. Without it, a plant can’t get
nutrients from the soil and the stem
(containing the leaves and flowers)
will not be able to grow upward.
Monocots, including grasses have
FIBROUS ROOT SYSTEM which
consists of a mat of thin, long, slender
lateral of about the same size that is
spread out below the soil surface.
TAPROOT SYSTEM, which consists
of one large, vertical root that
produces lateral or branch roots that
are most-likely common to Dicot plants.

♠ STEM
Underground stems, by being
situated below the surface of the
soil, protect themselves against
unfavourable conditions of weather
and the attack of animals, and serve
as the store houses for reserve food
and in vegetative propagation. The
underground stems are of four
types: RHIZOMES BULBS
CORMS TUBERS.

Rhizome is a horizontal
underground stem of some plant that
sends out roots and shoots from its
nodes. Gingers are RHIZOMES.
♠ Rhizomes

Bulbs are underground buds with
the stem reduced to a small knob on
which fleshy storage leaves are
clustered. A good example of a bulb is
an ONION (sibuyas).
♠ Bulbs

Corms are upright underground
fleshy stems covered by leaves reduced
to dry, covering scales.
♠ Corms

Tubers are fleshy underground
stems modified to store STARCH. The
“EYES” are the nodes with an axillary
bud in each (the peel is periderm
tissue). Sweet Potato (kamote) is an
example of Tubers.
♠ Tubers

♠ LEAF
Leaf is a flattened, green, lateral
appendage that carries out the function
of photosynthesis and transpiration. It is
also responsible for taking in CO2 and
releasing O and water vapour.
CHLOROPHYLL is responsible for the
leaf’s green colour.

♠BRACTS
Bracts are the
leaves at the base
of the flower.

Tendrils are
modified special
shoots with thin,
modified stems.
♠ TENDRILS

Stolons are sometimes called
RUNNERS; they are thin, above
the ground, horizontal stems of
indeterminate growth and long
internodes that grow out from the
parent plant.
♠ STOLONS

Plants organs are composed of
three (3) tissue systems:
♣ Dermal
♣ Vascular
♣ Ground

It is the
surface of
the plant. It
principally
protects the
inner tissues
in the plant.
♠ Dermal

It is composed of
XYLEM and PHLOEM,
which function in the
transport of water and
dissolved substances.
♠ Vascular

There are 3 types of Ground tissues:
♣ PARENCHYMA
♣ COLLENCHYMA
♣ SCLERENCHYMA
♠ Ground

Parenchyma is located throughout
the plant. It has a spherical shape. It
is assigned for PHOTOSYTHESIS,
REGENERATION, STORAGE and
RESPIRATION.
♠ Parenchyma

Collenchyma is located beneath the
epidermis in young stem and in leaf
veins. It has elongated cells with
unevenly thickened cell wall. Its
function is to the flexible support
system.
♠ Collenchyma

Sclerenchyma is located in the
fibers in woods, bark, leaves, and
stems. Its assigned or the structural
support.
♠ Sclerenchyma

PROCESS OF PLANT
GROWTH AND
DEVELOPMENT

A plant’s growth and development,
on its processes. Growth is irreversible
increase in mass results from the cell
division and cell expansion while
development is the sum of all changes
that progressively happens in an
organism’s body.

MERISTEMIC TISSUES are
responsible for the division of new cells
where zones are actively dividing cells
can be found and where it allows the
organisms to have indeterminate growth
which insures that plant can grow
throughout its life.

Cell division occurs solely in
meristemic regions, while expansion may
occur anywhere.
There are three (3) types of
zones.
• Zone of Cell Division
• Zone of Elongation
• Zone of Differentiation
♠ ZONES

Zone of Cell Division
It is the region of actively dividing
cells and provides plant growth.
Zone of Elongation
Cells in this region grow
longitudinally causing the root to grow
longer.
Zones of Differentiation
Region of mature primary tissues
where active water and minerals are
found.

Meristematic tissues are groups
of young cells that undergo
continuous state of division. These
tissues are mostly found at the
APICES of ROOT and SHOOT.

Meristemic stems, their characteristics
are:
♣They are living and thin walled.
♣Vacuoles are few and small in sizes
♣The cells contain dense protoplasm and
conspicuous nuclei
♣The cells are SPHERICAL, OVAL or
POLYGONAL in shape.
♣They do not store reserve food material
and are in an active state of
metabolism.

There are three different types of
Meristems:
♣Promeristem or Primordial Meristem
♣Primary Meristem
♣Secondary Meristem

It is a group of meristematic
cells of a growing organ. It is the early
embryonic meristem from which other
advanced meristems are derived. In a
plant, it occupies a small area at the
tip of the stem and root.
♠ PROMERISTEM or
PRIMORDIAL MERISTEM

They are present under
the Primordial Meristem at the
shoot and root apices.
♠ PRIMARY MERISTEM

It is derived from
primary permanent tissues which
have the capacity of division.
♠ SECONDARY MERISTEM

Earth and Life Science- How Plants Survive

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