Plant structure,
growth, and
reproduction

Plants, like multi-cellular
animals, have organs
composed of different
tissues, which are in turn
are composed of cells.

STRUCTURE AND FUNCTION
2 Major groups of Angiosperm:
1. Monocots
2. Eudicots/Dicots

3 Basic organs:
1. Roots
2. Stems
3. Leaves

2 types of buds

Modified roots, stems, and leaves

Modified roots, stems, and leaves

Modified roots, stems, and leaves

3 TISSUE SYSTEMS
Tissue?
Xylem tissue- contains water-conducting cells
that convey water and dissolved minerals upward
from the roots
Phloem tissue- contain cells that transport
sugars and other organic nutrients from leaves
or storage tissues to other parts of the plant

3 types of tissues
• Dermal
• Vascular
• Ground
TISSUE SYSTEM*
- *A functional unit connecting all of the
plant’s organs
- Each tissue system is continuous throughout
the entire plant body, but the systems are
arranged differently in leaves, stems, and
roots.

DERMAL TISSUE SYSTEM
- Plant’s outer protective covering.
- In many plants, the dermal tissue system consists
of a single layer of tightly packed cells called
epidermis.

VASCULAR TISSUE SYSTEM
- It is made up of xylem and phloem tissues and
provides support and long-distance transport
between the root and the shoot system.

GROUND TISSUE SYSTEM
- It accounts for most of the bulk of young
plant, filling the spaces between the
epidermis and vascular tissue system.
- Ground tissue internal to the vascular tissue
is called pith, and ground tissue external to
the vascular tissue is called cortex.

5 major types of Plant cells
1. Parenchyma cells
- Are the most abundant type of cell in most plants.
- It performs most metabolic functions of a plant,
such as photosynthesis, aerobic respiration, and
food storage.

5 major types of Plant cells
2. Collenchyma cells
- These cells provide flexible support in
actively growing parts of the plant; young
stems and petioles.

5 major types of Plant cells
3. Sclerenchyma cells
- Have thick secondary cell walls usually
strengthened with lignin, the main chemical
component of wood.
- Mature sclerenchyma cells cannot elongate and
thus are found only in regions of plant that have
stopped growing in length.
- 2 TYPES OF SCLERENCHYMA CELLS: FIBER, is long
and slender and is usually arranged in bundles.
SCLEREIDS, which are shorter than fiber cells,
have thick, irregular, and very hard secondary
walls.

5 major types of Plant cells
4. Water-conducting
cells
2 types:
Tracheids, are long, thin
cells with tapered ends.
Vessel elements are wider,
shorter, and less tapered.
- Both tracheids and vessel
elements are dead when
mature, with only their cell
walls remaining.

5 major types of Plant cells
5. Food-conducting cells (sieve-tube
elements)
- arranged end to end, forming tubes as part of
phloem tissue.
- It remains alive at maturity, though they lose
most organelles, including ribosomes and
nucleus.

PLANT GROWTH
2 Kinds of growth:
Determinate (animals)
Indeterminate
- allows plant to continuously
increase its exposure to sunlight, air
and soil.

3 categories of flowering plants:
Annuals-
Biennials-
Perennials-complete
their life cycle in a single year
or less
complete their life cycle in two years,
with flowering and seed production
usually occurring during second year.
are plants that live and reproduce
for many years.

Growth in all plants is made possible by
tissues called MERISTEM.
Meristem- consists of undifferentiated
(unspecialized) cells that divide when
conditions permit, generating additional
cells

Meristems at the tips of
the roots and in the buds
of shoots are called
APICAL
MERISTEMS.
A process called
PRIMARY GROWTH
produces the new cells
that enable a plant to
grow in length

3 zones of Root
Primary growth:
1. Zone of cell
division
2. Zone of
elongation
3. Zone of
differentiation

Vascular cylinder
differentiate into
PRIMARY
XYLEM and
PRIMARY
PHLOEM.

SECONDARY GROWTH
- Is the thickening in older regions where
primary growth has ceased.
“the increase in thickness of stems and roots”
- is caused by the activity of dividing cells in
tissues that are called Lateral Meristems.

2 Cylinders:
1. Vascular
Cambium
a cylinder of meristem cells one cell thick
between the primary xylem and primary
phloem

2 new tissues of Vascular Cambium:
a. Secondary xylem (interior)
b. Secondary phloem (exterior)

Cork- are dead cells and have thick, waxy walls that protect
the underlying tissues of the stem from water loss, physical
damage, and pathogens.

Cork is produced by meristem tissue called the
Cork Cambium.

REPRODUCTION OF FLOWERING
PLANTS

The flower is the organ
of sexual reproduction in
angiosperm.
4 types of modified
leaves (FLORAL ORGANS):
1. Sepals
2. Petals
3. Stamens
4. Carpels

Sepals- enclose and
protect the flower bud
Petals- are often
colorful and advertise
the flower to
pollinators
Stamen- consists of a
stalk (filament) tipped
by an anther.
Carpel- has long
slender neck (style)
with a sticky stigma at
its tip.

Life cycle of an Angiosperm