Plant Reproduction

making more of a species

Two Forms of Plant Reproduction

Sexual Reproduction

Asexual Reproduction

Meiosis +

Fertilization

Mitosis +

Vegetative Propagation

Definitions2 Types of Reproduction:

1. Sexual Reproduction – when a seed is made that will reproduce a plant. Requires 2 plants.

2. Asexual Reproduction – Utilizing a part or parts of 1 parent plant. The new plant is a clone (exact duplication) of its parent

Sexual reproduction occurs in many kinds of plants in different ways. Some plants form pollen that fertilizes eggs in the flower or cone, others produce spores.

Angiosperms reproduce using their flower structure:

The petals attract insects and birds to encourage

pollination.

The stigma, style, and ovary make up the

female structure – the pistil. The ovary houses the ovules (eggs) before

and after fertilization

The anther and filament make up the male structure

– the stamen - that produces the pollen.

Summary: Stages of Reproduction

1. pollination – the transfer of pollen from the stamens to the pistils of a flower

2. fertilization (seed production) – the joining of an egg cell and a sperm cell

3. seed dispersal – moving seeds from one place to another

4. germination – the sprouting of a plant from a seed

Pollination• Pollination is the transfer

of pollen from anther to the stigma of the carpel

• self-pollination (same plant)

• cross-pollination (different plant; same species)

• Pollen grain germinates (forms pollen tube)

• Double fertilization occurs

Plant Reproduction Basics

• Sperm travels to embryo sac by way of a pollen tube

• Once sperm fertilizes egg, zygote becomes embryo (within ovule)

• Ovule develops into seed

• Ovary becomes fruit

• Germination of seed creates new sporophyte (which develops into a mature organism)

Figure 40-14

POLLEN TUBE GROWTH AND FERTILIZATION

Pollengrain

Stigma

Style

Ovary

Tube-cellnucleus

Pollen tube

Sperm

Doublefertilization

Synergid

Micropyle

Primaryendospermnucleus(3n)

Zygote(2n)

4. One sperm unites withegg to form zygote.The other fuses with thetwo polar nuclei to formendosperm (nutrient tissue).

3. Pollen tube completesgrowth toward the egg bypassing through microphyleand discharging the twosperm into a cell adjacentto egg.

2. The tube-cell nucleusmoves into pollen tube,and the generative cellnucleus divides by mitosisto form two sperm inpollen tube.

1. Pollen grain germinateson the stigma. Pollentube begins growingdown the style.

The Seed

Parts of a Seed

Embryo- The young multi-cellular organism before it emerges from the seed

Endosperm- A source of stored food, consisting primarily of starches

Seed Coat- Consists of 1 or more protective layers that encase the seed

Cotyledon- A seed leaf that stores food in the form of starch and protein for use by the embryo

Epicotyl- The portion of the embryonic stem above the point at which the stem is attached to the cotyledon(s)

Getting the seeds dispersed (moving them)

Flowering plants have different adaptations to enable their seeds to be dispersed as far away as possible.

The different methods of seed dispersal are…

by wind by animals by water by splitting open forcefully

Germination

Once the seed has been dispersed, it must germinate in order to grow.

Some seeds do not grow right away because they become dormant.

Dormant – Resting stage, no active growth

Germination Germination – A seed sprouting or

starting to grow To germinate the seed must be

placed in certain favorable conditions. Seeds need: 1. Water2. Air3. Temperature4. Light

Monocot Germination

Dicot Germination

Summary: Stages of Reproduction

1. pollination – the transfer of pollen from the stamens to the pistils of a flower

2. fertilization (seed production) – the joining of an egg cell and a sperm cell

3. seed dispersal – moving seeds from one place to another

4. germination – the sprouting of a plant from a seed