Plant Anatomy and

PhysiologyJust the Concepts

Anatomical Features and

Their Functions

Objectives• Describe the structures, types, and the function of

seeds;• Describe the components, the types, and the functions

of roots;• Describe the structures, types, and the functions of

stems;• Describe the structures, types, and the functions of

leaves;• Describe the major parts of a flower and their

functions;• Describe the types and forms of flowers; and • Describe the structures, types, and the purpose of

fruit.

Plant Parts• Vegetative parts

o Stemso Rootso Leaves

• Reproductiveo Flowerso Fruitso Seeds

Seeds• Types of seeds

o Monocot• These seeds have one cotyledon

o Dicot• These seeds have two Cotyledons

Bean Seed

Seeds• Seed Structures

o Seed Coat• Protects the fragile contents of the seed until germination

conditions are met• Germination: When the seed sprouts

o Embryo• Tiny plant that eventually grows into a mature plant

o Cotyledons• Embryonic leaves that are the first to emerge from the soil surface• Food storage in dicots

Seeds• Seed Structures

o Epicotyl• Becomes stem

o Plumule• Becomes leaves

o Radicle• Becomes root

o Endosperm• Food Storage in monocots

Seeds• What are seeds used for?

o Protect genetic information of the new planto Nourish it when it germinates

• The seed coat protects a seed while it is transportedo How can a seed be transported?

• Air• Water• Animals

o How?

Roots• Types of roots

o Fibrous root system• Many small roots spreading throughout the soil

with no main root structure• Example: Grass, Petunia, Palm

o Taproot system• One central root with many small branches

spreading throughout the soil• Example: Carrot, Radish, Beet

Roots• Parts of roots

o Primary Root• First root to emerge from the seed

o Secondary Root• Sometimes called lateral roots• Branch out through the soil

o Root Cap• Cell division causing root growth is

done hereo Root Hairs

• Smallest parts of the root• Absorb water that contains dissolved

nutrients

Roots• What does a root do?

o Grows in the soil (or other media)o Two or three things

• Provides anchorage• Absorb water and nutrients• Sometimes store food for the plant

o In the form of sugars

Stems• Stems can look very different

depending on the species of planto Can be vertical or horizontalo Some are modified for climbingo Some store water or food

• Types of stemso Herbaceous stems

• No stiffened ligneous structure• Generally frail• Example: Tulip, Grass, most annual plants

o Ligneous stems• Contain rigid structures, usually known as

wood • Very strong• Example: Trees, Shrubs, Bushes

o Specialized Stems• Several different types • Modified to serve a specific purpose for the

plant

Stems• Specialized Stems

o Bulb• Short flattened stem with several fleshy leaves• Grow beneath the soil• Produces a new plant each year

o Corm• Spherical structure similar to a bulb• No layers• Dies each year but produces new corms for the following year

o Rhizome• Underground stems that grow horizontally• New plants will sprout and emerge as this stem creeps under the soil surface

o Stolon• Similar to the rhizome, but grows above ground• Can be called a runner

o Tuber• It is the end of a rhizome that has swollen up with stored food• New plant will grow from the eyes of the tuber

o Tendril• Slender structure used to attach to a support• Can be twisty, sticky, or hooky

Stems• Parts of a stem

o Internode• Section of stem between nodes

o Node• Location on stem from which leaves and branches

growo Terminal bud

• AKA – apical bud• Bud at the end of stem growth• Usually found on perennial plants

o Axillary bud• Form at the node and produce a new stem

o Xylem • Vascular tissue in the stem that moves water and

dissolved nutrients from the root to the rest of the plant

o Phloem• Vascular tissue in the stem that moves food that

was made in the leaves to other parts of the planto Xylem up – Phloem down

Stems• What do stems do?

o All stems• Provide support• Position the leaves• Responsible for size and shape of the plant• Transport water, nutrients, and food• Allow new growth

o Some stems• Green stems produce food• Store food• Distribute growth

Leaves• Parts of a Leaf

Leaves• Parts of a Leaf

o Stomata• Very important pores found on the underside of most leaves• Allow water and oxygen to escape and carbon dioxide to enter

Leaves• Types of Leaves

o Simple Leaf• Has only one blade on the petiole

o Compound Leaf

• A leaf with many blades

Leaves• Types of Leaves

o Vein Pattern• Parallel

o Veins never cross, run parallel to midribo Found in monocots

• Pinnateo Veins branch off the midribo Found in dicots

• Palmateo Veins form a network, originate from common point at the

base of the bladeo Found in dicots

Leaves• Leaf Arrangement

o Three Types • Alternate

o Leaves grow one at each node alternating one side of the branch or stem to the other

• Oppositeo Leaves grow two at each node on either side of the branch or

stem• Whorled

o Leaves grow several at each node rotating around the branch or stem

Leaves• What do leaves do?

o Photosynthesis!• They make food for the plant

o Transpiration• Cool the plant

o Some leaves store food

o Leaf blade collects sunlighto Petiole supports the leaf and holds it away from the stemo Midrib provides structure to the leaf and transport food and water

Parts of a Flower

Parts of a Flower• Petals

o Colorful leaf-like structureso Attract animals and insects

• Peduncleo Stem of the flower o Provides support

• Sepalso Green leaves that protect the flower

before it opens

• Calyxo All sepals fused together

Parts of a Flower• Female: Pistil

o Stigma • Sticky part of pistil• Receives pollen

o Style• Rod that holds up stigma

o Ovary• Contains the eggs

o Ovule• Reproductive cell (eggs) that become seeds once fertilized

Parts of a Flower• Male: Stamen

o Filament• Stalk-like structure that holds up anther

o Anther• Sack-like structure that holds pollen

o Pollen• Contains reproductive cells

Flowers• Types of Flowers

o Sympetalous• Petals fused together

o Polypetalous• Many individual petals

o Actinomorphic• Symmetrical on many axis • Funnel or bell shaped

o Zygomorphic• Bilateral symmetry – only one axis

Flowers• Types of Flowers

o Terminal• Grow from the end of a branch or stem

o Axillary• Grow from the junctions of stems and leaves

Flowers• Types of Flowers

o Single Flower• Plant with a single flower growing at the tip of the stem

o Cluster• Three or more flowers branched together

o Inflorescence• Many flowers growing and blooming independently on one

peduncle

Flowers• Types of Flowers

o Perfect flower• Contains male and female parts

o Imperfect flower• Contains only male or only female parts, not both

o Complete flower• Contain sepals, petals, pistil, and stamen

o Incomplete flower• Missing either sepals, petals, pistil, or stamen

Imperfect flowers are always incompleteIncomplete flowers are not always imperfect

Fruits• Once fertilization occurs, the flower is no longer

needed and dries up. The ovary of the flower becomes the fruit of the planto Name some different fruits

o How are these fruits different?

o How are they the same?

Fruits• Types of fruits

• Fleshy fruito Fibrous structure that surrounds the seedo Pome

• Several seedso Drupe

• Single seed

• Dry fruito Formed in a pod or hullo Pod

• Definite seamo Hull

• No seamo Caryopsis

• Thin wallo Samara

• Wings attached

Fruits• What do fruits do?

o Seeds are produced in the fruito Protects the seedo Provides a mode of transportationo Offers the seedling a bit of fertilizer

• Directly and/or indirectly

• Fruits are generally the most valuable part of a crop

• Fruits must be sufficiently mature to guarantee viable seedso Why is it important to the plant for seeds to be produced?

Fruits• Does a producer (like a farmer) want their plants

to produce seeds? o This is a trick question

• Some plants are grown to produce as many seeds as possibleo Like what?

• Some plants are grown to not have seedso Like what?

Fruits• Fruit or Veggie? That is the question

o Carroto Appleo Peacho Celeryo Cucumbero Tomatoo Watermelono Zucchinio Green Beano Coconuto Pinto Bean

Veggie

Fruit

Fruit

Veggie

Fruit

Fruit

Fruit

Fruit

Fruit

Fruit

Seed