Chapter 3:Lesson 2: Reproduction in Plants:

Plant Kingdom Non-flowering Plants Flowering Plants

Non - flowering Plants Do NOT produce flowers Mosses Ferns Gymnosperms Do NOT produce flowers

Plant Classification Plants Non-flowering Flowering: where seeds are protected in fruits. Naked seeds ( cones) Spore-bearing Gymnosperms No roots with roots Mosses Ferns

Seed bearing plants: Seeds in plants are either: 1- Gymnosperm: naked seeds, protected only by seed coat. 2- Angiosperm: a flowering plant which has seeds protected by a fruit.

Gymnosperms Pine tree

Non- flowering, seed bearing plants: Conifers: plants where seeds are found in cones. Example: pine tree (it grew from a seed). Male pinecones : produces pollens that contain sperms. Female pinecones: have ovules that contain eggs . Mature male cones release millions of pollen grains ( dust cloud) which are blown by wind & settles on ovules when sperms from pollen fertilize the eggs giving seeds. Note: seeds have wings that travel by wind & when it lands on a suitable habitat a new tree begins to grow.

Female cones Male cones

Characteristics of Gymnosperms .needle-shaped leaves. .vascular tissues (transport). .cones with reproductive structures. .naked seeds in female cones. .dry places.

Seeds VS Spores: Seeds enable plants to grow in many environments. Seeds ( unlike spores) don’t need water for fertilization).

Flowering Plants:( 86%) Have flowers instead of cones. They produce seeds inside fruits. Angiosperm: a flowering plant that has seeds protected by fruits. In angiosperms : - seed development is more complex. -protected seed live in all parts of the world.

Flowers: Are the organs of reproduction in flowering plants. Flowers start as buds protected by sepals.

Parts of the flower include: Sepals: enclose the flower bud and protect it until it opens Petals: are often like advertisement for flowers they attract pollinators

Female reproductive organ Pistil *Stigma Sticky surface that collect pollen. *Ovary –contains ovules after fertilization the ovary develops into fruit . *ovules (produce eggs that are fertilized by sperms from pollen & develop into seeds). Stamen *Anther – makes pollen. * Pollen tube- grows from pollen grain. The tube enables the sperm to travel into ovules to fertilize eggs.

Pollination: Transfer of mature pollen grains from the anther to the stigma. -wind -insects -birds & other animals

When a pollen grain lands on the stigma, it germinates and a pollen tube grows down through the style to an ovule (egg)

1-Sugary nectar and 2- scent present. flowers are adapted to attract pollinators (insects) to them to enable transfer of pollen. 1-Sugary nectar and 2- scent present. 3-Brightly coloured petals that lure animals. Sticky stigma to collect pollen Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

Fertilization The sperm travels through the pollen tube to the ovule. The sperm & egg fuse forming the zygote (fertilized egg) –this grows into the plant embryo. The embryo is a tiny plant that develops in the ovules.

Ovule wall develops into a protective coat. *The ovule forms the seed and the ovary forms the fruit. A fruit is a ripened ovary

Seed dispersal: Wind dispersal - Flight mechanisms, like parachutes, wings. Water dispersal - Plants near water create floating fruits ex. coconuts Animal dispersal - Fleshy fruits which animals eat, drop undigested seeds in feces or burrs which stick to animals’ coats

Angiosperm life cycle: 1) Pollination. 2) Fertilization. 3) Embryo development. 4) Fruits develop. 5) Seeds disperse. 6) New plant grow.

Germination: Seeds germinate or sprout only when conditions are right for the embryo growth.( a thick hard seed coat protect the embryo until the seed germinate). To germinate seeds need: 1) enough hours of light. 2) Warm soil (usually Spring). 3) Water.

Germination: Timing for the seeds to germinate depends on the needs of the plant. Sometimes seeds stay in the ground for several years before conditions are right for growth. When the time is right: Seed absorbs water & expand, breaking the seed coat & embryo begins growing. First the root emerges from the seed & begins to anchor the embryo & take water up. Then a shoot pushes up.

Germination:

Germination: The embryo growth needs energy, but from where does the energy comes from?? Cotyledons: contain food that provides energy until the plant can make its own food. When leaves emerge from the ground, they turn green, as chlorophyll for photosynthesis is produced. Finally, rapid growth begins.( embryo turns into a plant seedling).