Structures Of Seed Plants Ch 12.4 7th

Chapter 12 Section 4

List 3 functions of roots and 3 functions of

stems. Describe the structure of a leaf. Identify the parts of a flower and their

functions.

The deepest roots ever discovered belonged to

a wild fig tree in South Africa. The roots penetrated the soil to a depth of more than 120 meters!

http://blogs.bootsnall.com/km/files/2007/04/bz_figtree.jpg

Root system:  roots

Shoot system:  stems & leaves

Vascular Tissues of the root & shoot systems:  Xylem – transports water & minerals from shoots to roots  Phloem – transports food molecules to all parts

Most are underground 3 Main Functions:  Supply plant with water & dissolved minerals  Hold plants securely in the soil  Store surplus food made during photosynthesis

(sugar & starch)

Epidermis:  Layer of cells that covers the surface of the roots

Root Hairs:  Cells that extend from the root to increase the

surface area Root cap:  Protects the tip of the root  Produces a slimy substance (easier to push

through soil)

http://www2.volstate.edu/MSD/BIO/1020/lab11s6.jpg

• Taproot System: • One main root • Grows downward • Smaller roots branch off • Can reach water deep underground • Ex: dicots, gymnosperms

http://www.scq.ubc.ca/wp-content/uploads/2006/08/plantroots.gif

Fibrous Root System: Several roots spread out from the

base of a plant’s stem Roots are usually the same size Get water from close to the soil surface Ex: monocots

Vary in shape and size Usually located above ground Stem Functions:  Connects plant’s roots to its leaves and flowers  Supports the plant body  Transport material between root and shoot

systems  Stores materials (ex: cactus stores water)

Soft Thin Flexible Ex: wildflowers, clovers, poppies, beans,

tomatoes, corn

Trees and shrubs have woody stems Live in cold winters (dormant) with growth in

the spring and summer Beginning of each growth period: large xylem

cells are produced As Fall approaches cells become smaller and

darker (growth rings)

Vary greatly in shape (round, narrow, heart-shaped, fan-

shaped) Vary in size (ex: Duckweed vs. Rafia Palm)

http://i.bnet.com/blogs/duckweed.jpg

http://www.rarepalmseeds.com/images/RapRuw.jpg

Main function: make food for the plant Chloroplasts capture energy from the sun Leaves absorb CO2 from the air Make food (sugar) from CO2 and H2O

Related to their function:  photosynthesis

Cuticle: outer surface, prevents water

loss Epidermis: single layer of cells below cuticle Stomata: tiny openings for CO2 to enter Guard cells: open and close the stomata

http://phsgirard.org/APbiology/Chapter35/LeafStructure.jpg

Most photosynthesis takes place here 2 layers: Upper layer: Palisade (contains many

chloroplasts) Second layer: Spongy layer (xylem & phloem

here, CO2 moves freely)

http://extension.oregonstate.edu/mg/botany/images/fig12a-big.gif

Cactus leaves = spines Sundews catch insects

http://www.nature-gifts.com/graphics/3305-sundew-plant-l2.jpg

Adaptations for sexual reproduction Many shapes, colors, fragrances Many flowers produce nectar (fluid that

contains sugar)

Sepals:  Outermost ring, protects the bud  Often green  Cover and protect the flower while it is a bud

Petals:  Broad, flat, thin leaf-like parts  Attract insects  Animals help reproduction by carrying pollen

Stamens Pistils

Stamen:  Found just above the petals  The male reproductive structure of flowers  Thin stalk called a filament, topped by an

anther  Anthers are sac-like structures that produce

pollen

http://upload.wikimedia.org/wikipedia/commons/c/c5/Stamen_(PSF).png

Pistil:  Female reproductive structure of flowers  One or more  Tip is called the stigma (pollen grains collect here)  Style: the long, slender part of the pistil  Ovary: rounded base containing an egg in an ovule  Ovule develops into a seed, ovary develops into a fruit

http://www.wsd1.org/argyle/environmental/outdoorclassroom/Entries/2007/2/21_Hand_Pollination_of_Strawberry_Blossoms_files/flower12.gif

 Help plants reproduce  Flower arrangements  Food: artichokes, broccoli, cauliflower  Make tea: chamomile, hibiscus  Spices: saffron, cloves  Perfumes, shampoos, lotions

Why do some plants have brightly colored

flowers and other plants do not? Describe 2 types of root systems, and list one

plant that has each type