Kingdom Plantae

The plant kingdom is in the domain

Eukarya and in the

supergroup Archaeplasti

da

Common Ancestor

• The closest living relative of plants are in the green algae are charophytes

• At one time they had a common ancestor

Traits Common to Green Algae and First Land Plants

• Same rose-shaped cellulose synthesizing complexes

• Both have peroxisome enzymes for photorespiration

• Same cell wall formation• Flagellated sperm• Apical meristem to increase in length

and produce specialized tissue• Both contain plasmodesmata or pores• Cellular/chloroplast DNA similarities

Terrestrial Advantages

• More light (water reduces light reaching plants

• More CO2 available for photosynthesis

• More minerals found in land

• Few predators

Disadvantages

• Less support (water gives more support than air)

• Preventing desiccation (drying out)

• Need for water (metabolic processes)

• Reproductive barriers - bringing gametes together and preventing them from drying out

Land plants

evolved new

emergent

properties

to adapt to life on

land

Four Derived Traits of Terrestrial Plants

1. Exhibit alternation of generations producing an embryo that is for some time dependent upon the female gametophyte.

2. Plants produce spores coated with “sporopollenin” to prevent dehydration and waxy cuticles for other plant parts.

Four Derived Traits of Terrestrial Plants

3. Multicellular gametangia to produce eggs and sperm.

4. Apical meristem- Area found on the tips of shoots and roots and other locations that specialize in the process of mitosis.

Alternation of Generations

• Parental generation is diploid (2n) with two sets of chromosomes and called the sporophyte generation

• Sporophyte form sporangia that will have cells inside that undergo meiosis to produce haploid spores (1n) one set of chromosomes

• Spores may be of different sizes-megaspores and microspores

Alternation of Generations

• Spores becomes the gametophyte generation

• Megaspore produces a gametophyte via mitosis that contains an archegonium that produces an egg

• Microspore produces a gametophyte that contain an antheridium that produces sperm

• Gametophyte and sporophyte generation look nothing alike

Through evolution, the sporophyte generation has become more

conspicuous than the gametophyte generation

Protected Spore

Plants

produce spores

coated with “sporopolle

nin” a polymer to

prevent dehydration

in multicellular compartmen

ts

Fossilized spores. Unlike the spores of most living plants, which are single

grains, these spores found in

Oman are in groups of four (left; one hidden) and two

(right).

Fossilized sporophyte tissue. The spores were

embedded in tissue that appears to be

from plants.

Multicellular Gametangia Produces Eggs and Sperm

Gametangia protects gametes

from desiccation

Apical Meristem found on the tips of shoots and roots specialize in the process of mitosis

(growth).

• In the course of evolution of land plants, major events occurred to include development of vascular tissue, stems, leaves, roots, seeds and flowers.

• There are major groupings include bryophytes, seedless vascular plants, and the plants that produce seeds and flowers.

Plant Groups

Bryophytes Mosses, Liverworts, &

Hornworts• Nonvascular land plants• Have structures that

resemble leaves and roots (rhizoids)

• Gametophyte dominant generation

• Seedless• Form spore capsules

(sporophyte)• Sperm swims to eggs

through water droplets

Mosses• Grow in moist

areas• Leaf-like

structures & rhizoids

• Archegonia (eggs) & antheridia (sperm) at top of gametophyte

• Sporophyte makes spore capsule on a stalk

Polytrichumcommune,hairy cap

moss

Sporophyte

Gametophyte

Liverworts

• Flattened body (thallus) with lobed like shape

• Form cup-like structure for reproduction

• Gametophyte generation dominant

Hornworts have a leafy gametophyte like moss and the sporophyte generation grows

out of and is dependent on the gametophyte.

LycophytesClub moss, Spike moss,

Quillwort• Have vascular tissue (conductive)• Xylem-moves water and minerals upward

and is strengthened with lignin in cell walls• Phloem moves water and organic nutrients

both up and down. • Leaves (microphylls with single strand of

vascular tissue) and roots evolved as extensions from the stem

• Sporophyte dominant• Microphylls contain sporangia at the top of

the plant in a strobili

Club moss with vascular tissue.

Microphylls containing

sporangia at the top of the plant.

Spike Moss

Quillwort

PterophytesFern, Horsetails, Whisk ferns

• Megaphylls or true leaves with branched vascular bundles

• Increased photosynthesis• Ferns have underground horizontal

stem (rhizome) and leaves (frond) that push up from the soil.

• The gametophyte generation is reduced

• Sporophyte dominant

The Life Cycle Of Ferns

Whisk Fern

• Lack megaphylls (leaves) and roots

• Made of only branching stems

• Have underground, horizontal rhizome

Horsetails

• One genus• Underground

rhizome produces aerial stems with whorls of side branches

• Cell walls with silica

Seed Plants

• Produce seeds in the sporophyte generation

• Seed consist of a seed coat, food, and sporophyte embryo

• Spores produced by the sporophyte generation are retained in the plant and are not released into the environment

Seed Plants

• All seed plants produce two different types of spores (heterospory)

• Microspores make the male gametophyte (pollen)

• Megaspores make the female gametophyte inside a structure called the ovule

Seed Plants

• The female gametophyte never leaves the sporophyte

• The ovule eventually becomes the seed once the egg of the female gametophyte is fertilized

• The entire male gametophyte is used to deliver the sperm cells

Seed Plants

• Seeds and pollen eliminates the necessity of water for reproduction

• Both can be carried long distances and have a thick coats to resist drying out

• Spread by wind, insects, animals, etc.

• Gymnosperms and Angiosperms both reproduce by seeds

• Gymnosperms make naked seeds protected in cones

• Angiosperms make seeds surrounded by a mature ovule (fruit)

• Angiosperms produce flowers to attract pollinators

Two Types of Seed Plants

Gymnosperms

• Gymnosperms do not produce fruit or flowers

• Conifers are the largest gymnosperm group with 575 species

• Most do not shed their leaves in the fall

• Includes pine tree, junipers, and sequoias

• It takes 2 years to produce a seed

Other Gymnosperms• Phylum Cycadophyta-

cycads have large cones and palmlike leaves

• Phylum Ginkgophyta-only one species surviving. Deciduous fan leaves with fleshy seeds

• Phylum Gnetophyta-species are found in tropics and desert

Flowering Plants• Phylum Anthophyta• A flower is a structure specialized

for reproduction• Flower can have both male and

female reproductive organs (Perfect flower)

• Imperfect flowers have only male (staminate flowers) or only female (pistillate flowers)

Flower Types

• If both male staminate and female pistillate flowers are on the same plant, it is monoceious

• Corn is a monoecious plant• If male staminate and female

pistillate flowers are on different plants, it is said to be dioecious

• Persimmon and ash are dioecious

Perfect & Imperfect Flowers

PERFECT COMPARISON

Parts of the Flower• Sepal-leaf like and protects the

floral bud• Petals-Usually showy with colors to

attract pollinators• Stamen-male reproductive organ

consisting of stalk like filament with anther (pollen sac)

• Pistil-female reproductive organ with sticky stigma at the top, stalk like style, and enlarged ovary (base) with ovules

Pollen

• In the anther chambers there are microspore mother cells (2n) that undergo meiosis to produce 4 microspores (n)

• Microspores undergoes mitosis to produce a spore with two nuclei, one becomes the tube cell and the other the generative cell

Pollen

• Generative cell will undergo mitosis once more to make two sperm nuclei (male gametophyte)

• This forms a very drought resistant pollen grain

Ovule

• Inside the ovary, there are one or more ovules

• Each ovule has a megaspore mother cell (2n) that produces 4 megaspores (n)

• Three of cells will degenerate but one will survive to give rise to female gametophyte

Ovule• Megaspore (n) will undergo three mitotic

divisions without cytokinesis to give rise to eight nuclei

• Cytokinesis then occurs to produce seven

cells - 3 on each end and 1 in the middle.

Ovule• One in the middle will have two distinct nuclei

(n+n)• On the top are three antipodal cells• At the bottom, there is a central cell which is

the egg cell (n).• It is flanked by two living cells called

syngerids.

Fertilization

Pollination and Fertilization

• Pollen falls on the stigma sending down a pollen tube making its way to ovule

• 2 sperm nuclei travel down the pollen tube to the micropyle (opening into the ovule)

• One sperm nucleus fertilizes the egg, and the second fertilizes the polar nuclei or large central cell – Double Fertilization

• Polar nuclei is now triploid or 3n and becomes endosperm (stored food)

Fertilized Egg to Seed• Fertilized egg or zygote will gives rise to the

seed embryo• Endosperm will provide nutrients to the

embryo• Ovule becomes the seed coat• The ovary under the influence of hormones will

become the fruit• Fruit or pericarp of the plant is used to protect

enclosed seeds and aids in their dispersal

Different Types Of

Fruits And Seeds:

Fruit is used to protect the

seed and entice

animals to eat to carry the seed to

another location.

Major groups of flowering plants ---Monocots and Eudicots (formerly

dicots)

Comparison Of Monocots Versus Dicots