Seed Plants

Characteristics of seed plants

1. Vascular tissue – leaves, stems and roots

2. Use seeds to reproduce

3. Have complex life cycle that include sporophytes and gametophytes

a. Plants that you see are sporophytes

Vascular Tissue - Two types of vascular tissue:

1. Phloem – vascular tissue through which food moves

a. Travels down to roots and stems

2. Xylem – vascular tissue through which water and nutrients move

a. Travels upward from roots to stems and leaves

Seeds

1. Seeds – structures that contain a young plant inside a protective covering

a. Do not need water to reproduce – sperm deposited right near egg

b. Seeds develop after sperm fertilize egg

2. Seeds have three important parts: embryo, stored food and a seed coat

Scanned picture of seeds

Parts of seeds

1. Embryo – zygote that develops into a young plant

2. Cotyledons - Seed leaves – where the food is stored

3. Either one or two cotyledons

4. Seed coat – outer covering of seeda. Also called “skins”

b. Protecting embryo and food

Seed Dispersal - Plants use many different ways to get their seeds dispersed

Use animals

Water transports seeds

Use the wind

Seeds shoot out of exploding pods

Germination

1. Germination – the early growth stage of the embryo

a. Begins when seed absorbs water from the environment

b. Roots grow downward first, then its leaves and stems grow upward

Leaves

1. Leaves – parts of plant that capture the sun’s energy and carry out photosynthesis

2. Transpiration – water evaporating in the leaves that will exit through the stomata

Cuticle

Upper leaf cells

Lower leaf cells

Surface cells

Chloroplasts

Vein

Xylem

Phloem

Stomata

Parts of Leaves

1. Upper leaf cells – traps sunight

2. Lower leaf cells – store carbon dioxide and oxygen

3. Cuticle – waxy waterproof layer on leaf

4. Stomata – tiny pores that let CO2 in and O2 out

5. Xylem – carries water to leaf

6. Phloem – carries food (photosynthesis) throughout plant

Stems

1. Stems have two functions:a. Carries substances through out plant

b. Provides support for plant and holds up leaves

2. Vary in size and shapea. Herbaceous – soft, dandylions, peppers

b. Woody – hard and rigid, tree

Structure of woody stems

xylem

Cambium – layer of cells inside phloem, these cells divide to make new phloem and xylem

Roots1. Roots - anchor a

plant in the ground and absorb water and nutrients from the soil.

2. Root cap – structure that contains dead cellsa. Protects root from

injury

QUESTIONS:

1.What three characteristics do all seed plants share?

2. List the three main parts of a seed. Describe the function of each part in producing a new plant.

3. What are the main functions of a plant’s leaves, stems, and roots?