Plant Structures and Functions

Ms. Russell

Basic parts of flowering plants are stems, leaves, flowers and roots

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Vegetative

Reproductive

Leaves and their Functions

• Photosynthesis– Light is intercepted and

plant sugars are manufactured

– Large flattened surface for maximum absorption of light energy

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Vein

Midrib

Petiole

Stem

Stipule

provide support for the leaf and transport both water and minerals (via xylem) and food energy (via phloem) through the leaf and on to the rest of the plant.

the central rib of a leaf - it is usually continuous with the petiole.

a leaf stalk; it attaches the leaf to the plant.

(also called the axis) the main support of the plant.the small, paired appendages (sometimes

leaf-life) that are found at the base of the petiole of leaves of many flowering plants.

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parallel

pinnate

palmate

Leaves have unique structures, called veins, that transports liquids and nutrients to leaf cells.

The veins run the same way, like cane plants

Veins diverge together like fingers on a hand going to the palm

There is a main nerve (the midrib) from where all the other nerves derive, like a plume.

Has undivided blades

Has fragmented blades with divisions reaching the midrib

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opposite

alternate

whorled

Two per node, facing opposite sides of them.

Springing one leaf per node at different levels of the node

Several leaves at the same level

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linear

lanceolate

ovate

Spear shaped.

Egg shaped

Cordate-heart shaped

Obovate

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entire

crenate

dentate

sinuate

serrate

lobed

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FunctionsFunctions• Support leaves and buds,

branches and reproductive structures

• Conduits for transporting water, minerals and manufactured food

• Some are modified for storage

Monocot vs. Dicot• Monocots - flower parts in

multiples of 3

• Dicots - flower parts in multiples of 4 or 5

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Two cotyledons (seed leaves)Two cotyledons (seed leaves)

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One cotyledon (seed leaf)

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node

internode

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StolonStolon Horizontal stem growing on

soil surface(strawberry plant)

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TuberTuber

Enlarged portion of underground stem

(potato plant)

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FunctionsFunctions

• Anchors plant• Nutrient and water

absorption• Food storage• Two basic root systems:

1. fibrous root 2. tap root

fibrous root

tap root

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FunctionsFunctions

ReproductionAttract pollinators

Reproductive Structures• Stamen–Anther - produces the pollen–Filament - stalk which supports

the anther

Reproductive Structures cont…

• Pistil–Stigma - has sticky surface to

capture pollen–Style - tube-like; connects stigma

with the ovary–Ovary - contains the ovules

• Groups of flowers–Complete flower - has all four

major parts (sepals, petals, stamens, and pistils).–Incomplete flower - lack one or

more of the major parts–Perfect flower – contains both

stamens and pistils

• Groups of flowers–Complete flower - has all four

major parts (sepals, petals, stamens, and pistils).–Incomplete flower - lack one or

more of the major parts–Perfect flower – contains both

stamens and pistils

Pollination and Fertilization• Pollination - when a pollinator

transfers pollen grains from anther to stigma• Fertilization - when pollen fuses

with the egg cell• VIDEO: http://www.unitedstreaming.com– Keyword: Pollen Trip; Title: The Pollen Trip

Influence on Flower Formation

• Photoperiodism - growth response of a plant to the length of day• Vernalization - process by which floral

induction in some plants is promoted by exposing the plants to cool temperatures for a certain length of time

• Phytochrome - pigment in cytoplasm of green plants; associated with the absorption of light that affects growth, development, and differentiation including flowering of a plant, independent of photosynthesis• Anthesis - release of pollen from the

anther

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solitary

raceme

spike

umbel

corymb

head

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• Mature ovaryMature ovary• Seeds are ovulesSeeds are ovules• Ovary wall may be Ovary wall may be

fleshyfleshy• Example fruit typesExample fruit types

• pomepome• podpod

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• Matured ovule• Parts

• seed coat – protective coating• embryo – miniature plant• endosperm – food storage organ

embryo area

endosperm

seed coat

1. What is the difference between a dicot and monocot?

2. What is photosynthesis?3. There are 3 types of leaf venation what is

one and what does it mean?4. What are 2 female parts and 2 male parts?5. What is the difference between a complete

flower and incomplete flower?