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Objective: Plants
Essential Question: How have the structures and
functions of plants enabled them to survive?
General Plant Structure

Plants are made up of three organs—Roots, Stem (or
trunk) and Leaves

Just like other organisms, plant organs are made up of
tissue systems and the tissue systems are made up of
cells.

3 main organs—3 Tissue Systems—3 Types of Cells.
3 Types of Basic Plant Cells



Parenchyma cells; found through out the plant—Fun Fact:
these cells are the reason plants can be regrown from a
clipping
Collenchyma cells; most common in the young tissue of
shoots and leaves—Fun Fact: These cells are often formed
into strands. Ex Celery strings
Sclerenchyma cells; The strongest. Found in parts of the
plant that are not growing anymore. Fun Fact: seeds and
outer casings of nuts are made of Sclerenchyma cells.
They also are the reason that pears have a gritty texture.
Plant Tissue Systems-Dermal Tissue System

Plants don’t have a skin so they have a dermal tissue
layer—covers the plant and protects it in a number of
ways

Called Epidermal Cells

The non woody parts of plants have epidermal cells made
of live Parenchyma cells

On some leaves epidermal cells secrete a way-coated
substance that becomes the cuticle which helps hold in
moisture for the plant

Outer bark is made of dead parenchyma cells
Plant Tissue Systems Con’t-Ground Tissue System

Provides support and stores materials in the roots and
stems. In leaves ground tissue is packed with a lot of
chloroplasts—the site of photosynthesis.

Surrounded by the dermal tissue, makes up most of the
inside of the plant.

Has all three simple plant cells—parenchyma, collenchyma
and schlerenchyma
Plant Tissue Systems Con’t-Vascular Tissue System
Transports water, mineral nutrients and organic
compounds all over the plant.
 Surrounded by ground tissue
 Made of two networks made of hollow tubes (kind of like
our veins and arteries) Each is made of different kinds of
vascular tissue that works to move different resources
through the plant
Xylem—Is vascular tissue that moves water and dissolved
mineral nutrients from the roots to the rest of the plant.
Phloem—Is the vascular tissue that carries the products of
photosynthesis through the plant.

Another Important Plant Tissue—
Meristem

Meristem tissue—groups of cells that are the source of new cells form this
tissue. Meristem cells are not specialized but when they divide some of them
form into specialized tissues.

Apical meristems lengthen the tips of roots and stems

Lateral meristems increase the thickness of plants and are found all along the
woody roots and stems
Plant Reproduction—
Reproductive organs covered by special
leaves

SEPAL—modified leaves that protect the developing flower. Often green but
can be brightly colored.

PETALS—layer just inside of the sepal. Modified leaves. Their bright colors
often help attract animal pollinators.
Monocot flower such as lilies often have SEPALS and PETALS that look the same.
These are called TEPALS.
Flowering plants not pollinated by animals usually have very small sepals and
petals or even none at all.
Plant Reproduction—
Reproductive Organs
Some Plants have only male or female parts but most have both.

STAMEN—the male structure of the flower. Each stamen has a stalk called a
FILAMENT that supports the ANTHER. Anthers produce pollen grains, the male
gamephytes.

The Inner most structure of the flower is made up of the female structure
called a CARPEL. Most flowers have several carpels fused together. This forms
a structure called the PISTOL.
Each carpel is made of three parts:
STIGMA—the tip makes sticky substance that holds pollen grains.
STYLE tube that leads from the stigma to the ovary
OVARY—female gametophyte that is found at the base of the flower.
Plant Reproduction—
FRUITS and SEEDS

Fruits and seeds are part of the reproduction of flowering plants

The function of fruits in flowering plants is to help with seed dispersal. Seed
dispersal is important because a plant that grows right next to its parent may
compete for sunlight, space, water and nutrients.

Seeds may stay dormant for a long period of time. This means the embryo
inside has stopped growing.

Seeds do not begin to germinate—break out of the seed coat and begin to
grow into a seedling—until they take up water. Water causes the seed to swell
and crack the seed coat. The Radical, or root emerges first. Water also
activates important enzymes in the seed.
Deep Thoughts about fruits and seeds….

What do you think is the adaptive advantage to water uptake causing a seed
coat to crack?

Predict why it is important for the fruit to ripen when it’s seeds are mature?