making more of a species Plant Reproduction making more of a species

Two Forms of Plant Reproduction Sexual Reproduction Asexual Reproduction Meiosis + Fertilization Mitosis + Vegetative Propagation

2 Types of Reproduction: Definitions 2 Types of Reproduction: Sexual Reproduction – when a seed is made that will reproduce a plant. Requires 2 plants. 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 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 pollination – the transfer of pollen from the stamens to the pistils of a flower fertilization (seed production) – the joining of an egg cell and a sperm cell seed dispersal – moving seeds from one place to another 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)

POLLEN TUBE GROWTH AND FERTILIZATION Figure 40-14 POLLEN TUBE GROWTH AND FERTILIZATION Pollen grain Stigma Double fertilization Tube-cell nucleus Pollen tube Primary endosperm nucleus (3n) Sperm Style Synergid Ovary Zygote (2n) Micropyle 1. Pollen grain germinates on the stigma. Pollen tube begins growing down the style. 2. The tube-cell nucleus moves into pollen tube, and the generative cell nucleus divides by mitosis to form two sperm in pollen tube. 3. Pollen tube completes growth toward the egg by passing through microphyle and discharging the two sperm into a cell adjacent to egg. 4. One sperm unites with egg to form zygote. The other fuses with the two polar nuclei to form endosperm (nutrient tissue).

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: Water Air Temperature Light

Monocot Germination

Dicot Germination

Summary: Stages of Reproduction pollination – the transfer of pollen from the stamens to the pistils of a flower fertilization (seed production) – the joining of an egg cell and a sperm cell seed dispersal – moving seeds from one place to another germination – the sprouting of a plant from a seed