Roots, Stems, Leaves, & Flowers Notes

I. Roots

Roots A. Functions Absorb water and minerals. Transport water up to the stem. Store water and food. Anchor.

B. Parts 1. Xylem X shaped center of the root = vascular tissue that transports water up to the stems.

2. Phloem =vascular tissue that transports food down from the leaves and stems. Roots have 4 bundles of phloem found in the “corners” of the xylem.

3. Cambium = Growth tissue that produces new xylem and phloem. Found between the xylem and phloem.

4. Cortex outside ring. Stores food and water.

5. Root Hairs = single-celled extensions on the root whose purpose is absorbing water.

6. Root tips Cap = hard tip that pushes through soil. Apical Meristem Meristem = Plant growth tissue.

C. two types of root systems 1. Taproot system composed of a few large roots examples: carrot, tree. 2. Fibrous root system composed of a mat of tiny roots. Example: grass

D. Mycorrhiza = mutualism = fungus and plant roots

E. Adventitious roots = roots that arise from some place other than the primary root.

F. Perennial roots = root system that survives from year-to-year as top of the plant is annually dormant.

G. Root Foods Carrots Radishes

II. Stems

A. Functions Transport materials between roots and leaves. Support leaves and flowers.

B. Parts Xylem Phloem Cambium/Meristem

herbaceous = a plant that is soft, green, and has a thin bark.

C. Types of Stems 1. Herbaceous monocot stem vascular bundles are scattered.

2. Herbaceous dicot stem vascular bundles form a circle.

3. Woody stem contains wood brown tough thick bark

D. Food Stems 1. Potatoes are called tubers. Swollen tip of an underground stem.

2. Onions are called bulbs. Small stem surrounded by thick, juicy leaves.

3. Celery is a stem.

III. Leaves

1. Function Photosynthesis! Transport Food Store Food

2. Parts A. Cuticle =waxy, waterproof covering. –Not made of cells.

B. Upper Epidermis –like skin. –made of cells.

C. Lower Epidermis –Stomata = holes that let CO 2 in and H 2 O out. –Guard Cells = cells that surround the stomata. –Transpiration = plants release water from stomata.

D. Palisade Layer –long, tall cells found under the upper epidermis. –Lots of chloroplasts! –Most photosynthesis occurs here!

E. Spongy Layer –Loose cells with lots of air space.

F. Veins Xylem –Bring water into the leaf. –Top of the vein. Phloem –Takes sugar from the leaf. –Bottom of the vein.

3. Turgor =pressure of water inside a plant cell –Causes the cell membrane to press against the cell wall. –Causes the cell to be stiff. –High Turgor causes the leaf to be rigid. –Low Turgor causes the leaf to be wilted.

IV. Flowers

A. Function of Flowers Flowers are for sexual reproduction. Flowers produce seeds and fruit.

B. Parts of a Flower 1. Pistil = female reproductive structure.

The Pistil contains three main parts: a. Stigma = top of the pistil where the pollen sticks. b. Style = stalk c. Ovary =bottom of the pistil. =produces ovules –Ovules are the female gametophytes.

2. Stamen = male reproductive structure Produces pollen Pollen is the male gametophyte 2 parts (1)Filament = stalk (1)Anther = pollen producing sac

3. Petals Modified leaves Often Colorful Often attracts pollinators Often produces nectar Protect the developing reproductive organs

4. Sepals Modified leaves Often green Protect the un-opened flower

C. Pollination = the transfer of the pollen from an anther to a stigma. Birds Bees Wind

D. Fertilization = Fusing of the male and female gamete. Flowers undergo double fertilization The results are the zygote and the endosperm.

E. Fruit = ripened ovary = if it contains seeds in an ovary wall, it is a fruit.

F. Seed Dispersal Tasty fruits and seeds are eaten and deposited in a nice pile of “fertilizer” Stickery fruits hang on to fur and britches Aerodynamic fruits are blown Floaty fruits disperse by water