Transcript PLANT STRUCTURE AND FUNCTION

PLANT
STRUCTURE AND
FUNCTION
THE PHYLOGENY OF
PLANTS…
Charophytes (green algae)
Bryophytes (non vascular)
Trachoephytes (seedless, vascular)
Gymnosperms (“naked seeds”,vascular)
Angiosperms (contained seeds, vascular)
Monocots / Dicots
Major Parts of a Plant
– Leaves

Where photosynthesis
occurs
– Seeds

Method of sexual
reproduction
– Flower

Site where
reproduction occurs
– Stem

Transports nutrients
and supports the plant
– Root

take in nutrients and
anchor plant
The Seed

Parts of a Seed
– Cotyledon

The first leaves of a plant
– Seed Coat

Outside covering of a seed
– Endosperm

Food storage tissue that nourishes
the embryo
– Embryo
– New plant developed after
fertilization
Types of Seeds
Monocots
– A seed with only one cotyledon
– All grasses are monocots
– Flower parts in threes
– Leaves with parallel primary veins
Dicots
– A seed with two cotyledons
– Flower parts in fours or fives
– Leaves with distinct vein network
– All broadleaf plants are dicots
Seed Parts
Fertilizationzygoteseed (embryo)
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Plumule- is like a
leave in its early
development becomes
the shoot
Hypocotyl- develops
into the stem
Radicle- Becomes
roots
Male Parts of the
Flower
Stamen- Makes up all male parts
Pollen- Male sex cell, similar to sperm
Anther- Sac-like structure on top of the filament
Filament- Short stalk that holds the anther
Female Parts of the
Flower
Pistil- Makes up all female parts
Ovules- Female sex cell, similar to the egg
Stigma- Sticky part of the system, catches pollen
Style-Tube that leads from the stigma to the ovary
Ovary- Place where ovule is fertilized by the
pollen, Turns into a fruit or seed coat
Primary Growth

Occurs in apical meristems of plant
– (found at tips of stems and roots)
PROBLEM!
IF THE CUTICLE BLOCKS WATER,
WHAT ELSE IS PREVENTED FROM
ENTERING/EXITING THE PLANT?
C O
!!
2
Solution?

STOMATA!
– Tiny pores in epidermis surrounded by
two guard cells!
– Open during the day! Why?
 PS
occurs during the day
 Transpiration necessary for cooling
VASCULAR TISSUE

2 MAJOR TYPES:
– XYLEM TISSUE
– PHLOEM TISSUE
– Found together in VASCULAR BUNDLES
– Arise primarily from apical meristem
– Arise secondarily from vascular cambium
XYLEM TISSUE
CONDUCTS WATER
 PROVIDES MECHANICAL SUPPORT
 2 TYPES OF XYLEM CELLS:

– TRACHEIDS:
– VESSEL ELEMENTS:
PHLOEM TISSUE
CONDUCTS SUGARS
 COMPOSED OF TWO CELL TYPES:

– SIEVE-TUBE MEMBERS
– COMPANION CELLS
Sieve tube members
Form sieve tubes to conduct sugars
throughout plant
 Lack nuclei, ribosomes, vacuoles, etc.

Vascular
bundle
xylem
Stems

Transports food, water, and nutrients

Supports the leaves and flowers
Parts of the Stem
– Xylem

Water and minerals travel up to other plant parts
– Phloem

Manufactured food travels down to other plant parts
– Cambium
– Separates xylem and phloem
Types of Root Systems
– Fibrous Roots
– Easier to transplant

Short, small, compact roots
– Tap Root
– Difficult to transplant, since
most of the tap root is cut-off

Tap root is primarily used for
storage of food

In both types, most nutrients
and water are absorbed by
root hair

Fibrous Roots
– Monocots
– Several roots of same size w/ branching

Roots can be adapted for storage of
nutrients:
– Example: Carrot (Taproot)
Sweet Potato (Fibrous Root)
Plant Processes
– Photosynthesis

Mixes light, water, and carbon dioxide in the presence of
chlorophyll to produce sugar and oxygen
– Respiration

Combines sugars and oxygen to give off water and heat
– Transpiration
– Loss of water through the leaves or stems
– Causes wilting when soil is dry
Animal
Water
Wind
Dispersal of Seeds
Gravity
Wind
Force
Plant Systems
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There are 3 main plant
systems:
Reproductive – this is the
flower structure
Transport – this is the
stem and roots and their
xylem and phloem
Energy – this is the leaf
and other areas of
photosynthesis.
Leaf Tissue – What
happens where?