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

Plumule- is like a leave in its early development becomes the shoot

Hypocotyl- develops into the stem

Radicle- Becomes roots

Fertilizationzygoteseed (embryo)

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

Gravity Wind Force

                         

Animal

                         

Water Wind

Dispersal of Seeds

Plant Systems 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?