1. Chapter 22 The Plant Kingdom

2. Plants
What are plants?
Eukaryotic, multicellular organisms that have chlorophyll and carry out photosynthesis
For the most part, they are terrestrial
Live in almost all types of environment
Can be big, or can be small
Remember, they are autotrophic!

3. Plants are Invading the Land!
About 500 million years ago, a group of green algae developed adaptations that enabled them to invade the land.
Over 85% of land plants are flowering plants, the Angiosperms.
14% are mosses and ferns.
1% are conebearing plants (Gymnosperms).
The challenges to invading the land include:
preventing water loss
absorbing and transporting water
fertilization and protection of the embryo
Structural support

5. Alternation of Generations
Plants have a life cycle that involves two distinctly different generations
Sporophyte generation is diplod (2N) and has plant parts in which meiosis can take place to be haploid
Gametophyte generation is haploid (N) and develops structures that produce gametes
The gametes will be produced through mitosis
When two haploid gametes unite a diploid zygote is formed

6. Nonvascular Plants
Nonvascular plants include mosses, hornworts, and liverworts, and are commonly known as bryophytes
They all have these following characteristics
They lack vascular tissue
They do not have true roots or leaves
The gametophyte generation is the most prominent part of the life cycle
Sperm swim to the egg

7. Moss Life Cycle
The moss plant you generally see is the gametophyte generation
Two structures that produce gametes
Antheridium is made up of a jacket of cells surrounding the developing sperm
Archegonium is a flask shaped structure that produces the egg
When sperm mature, antheridian opens and sperm will swim through a film of dew or rainwater to archegonium
Sperm and egg nuclei fuse, diploid zygote is produced and is in the sporophyte generation

8. Vascular Tissue
Plants, excluding the bryophytes have a vascular system to transport water and nutrients throughout the plant
Roots are underground structures that anchor the plant and absorb water and minerals
Leaves are structures specialized for carrying out photosynthesis
Stems are structures which connect the roots with the leaves and position the leaves so they receive sunlight

9. Vascular Tissue Two kinds of vascular tissue: xylem and phloem
Xylem consists of a series of dead, hollow cells arranged end to end to to form a tube
Carries water and minerals up from the roots through the stem to the leaves
Phloem carries organic molecules (sugars, aa) produced in the leaves to other parts of the plant where growth takes place

10. Roots
Roots never stop growing by their tips to try and get new territory for available nutrients and water
Most roots are storage places for the food produced by the plant to store during harsher seasons
Some roots are a source of food for us, such as carrot, turnips, and radishes

11. Stems Two basic functions of stems: Support the leaves
Transport raw materials from root to leaves and food from leaves to roots
Inside the bark here are seven layers of xylem tissue. Each layer of xylem constitutes 1 years tree growth

12. Leaves Leaves carry out photosynthesis
Have a large surface area to try to collect as much sunlight as possible
Stomates open and close to control the rate at which water is lost and gases are exchanged
During times of drought, the stomates are closed to reduce the rate at which the plant loses water

13. Seedless Vascular Plants
Seedless vascular plants include whisk ferns, horsetails, club mosses and ferns
They have vascular tissue, but do not produce seeds
Not as limited to wet areas as nonvascular plants, because they have roots and vascular tissue.
Still need water to move sperm

14. Ferns Most abundant of the seedless vascular plants
Found in greater number in the tropics, but can be found throughout the world
Some are very small, while some can grow to be very large.
Some have trunks which are 79 feet high, and leaves that grow up to 16 feet long
The stage you see when looking at ferns are mostly sporophytes
The vertical leaves on ferns are known as fronds
On the underside of the fronds, the spore producing parts are located, known as sori (sorus)

15. Fern Life Cycle

16. Seed-Producing Vascular Plants
Seed is a specialized structure that contain an embryo, along with stored foot, enclosed in a protective coat, known as a seed coat
Two major groups of plants that produce seeds:
Gymnosperms (conifers)
Angiosperms (flowering plants)

17. Gymnosperms
Gymnosperms (naked seed plants) are plants that have cones (woody structures) where their seeds are produced.
Pollen grains are the male gametophytes, and the transfer of pollen is known as pollination.

18. Gymnosperm Life Cycle

19. Types of Gymnosperms
Cyads – are stout, woody gymnosperms that have a ring of fernlike leaves on the top that live in tropical regions.
Ginkgo trees- have fan-shaped leaves. There is only one species left, Ginkgo biloba. Reproductive strucutres of ginkgos are on separate trees.

20. Types of Gymnosperms
Conifers are the common trees and shrubs that bear seeds in cones and many have needle- shaped leaves.

21. Angiosperms
Angiosperms are plants that produce flowers and have their seeds enclosed in fruit.
Fruit is a modification of the ovary wall into a special structure that contains the seeds.
Flower is the structure, composed of highly modified leaves, that is responsible for sexual reproduction.

22. Flower Structure
Pistil is at the center of a flower, which is composed of the stigma, style and ovary.
Stigma is the terminal portion of the pistil and is meant to receive pollen.
Style is where the male gamete travels down into the ovary
Ovary is the female reproductive structure
Stamen is male organ of a flower
Filament is the stalk of the anther
Anther contains pollen sacs. The sacs release pollen on to the outside of the anthers that brush against insects on entering the flowers.

23. Flower Structure