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UNIT 2: TOPIC 3Plant Reproduction and Breeding
What is selective breeding? Choosing specific plants with particular
characteristics and encouraging those plants to reproduce
Plants are also bred to withstand environmental conditions such as:
Hardiness Yield Resistance to disease How well it stores
Heather, Calluna vulgaris, one of Britain's hardiest plants
Genetically Modified Plants Scientists combine genetic material from
two different plants, so it has genes from both.
Plant Reproduction
Asexual reproduction happens when a “parent” plant grows new plants from its foots, stems, or leaves.
Vegetative Reproduction
When young plants are identical to the parents- usually happens when a new plant grows from the root of another. Can also occur through stems
Grafting
To take a branch from one tree and attach it to another
http://www.youtube.com/watch?v=XpgbpbewU3E
Seed Plant ReproductionFemale Cone Male Cone
-Contains ovules-Catches pollen grains, and once the pollen tube grows down to the ovule, pollination occurs
-Smaller-Pollen grains develop on it
http://studyjams.scholastic.com/studyjams/jams/science/plants/flowers.htm
2. Pollination Occurs when
pollen has been transferred from the anther to the stigma. When the pollen grain germinates on the stigma it creates a burrow called the pollen tube as it travels toward the ovary
http://www.youtube.com/watch?v=wDM8OtS5MPM
3.
When the pollen grain reaches the ovule, fertilization occurs
4.
Pollination must take place before fertilization can take place
5.
The fertilized embryo will become a tiny new plant inside the seed
Pollination
Two types of pollination are self-pollination and cross- pollination
2 ways of cross-pollination
1. Wind 2. Animals
Artificial Pollination
When plant breeders breed plants for specific purposes
Once a plant has been pollinated, a seed is formed! Inside the seed is a tiny plant that is called an embryo. It is protected by a seed coat that helps it stay alive or dormant.
What conditions does a seed need to be able to grow?
Sunlight Water Air
When you bite into a pear you are eating a fruit! What is the function of fruit for a plant?
A fruit is the growing ovary of the plant that swells and protects the developing seeds of a plant until they are ripe.
Name 5 ways that seeds are spread
1. Wind
2. Water (ex. Coconut)
3. Eaten by animals
4. “Hitch a ride” on animals
5. Fire
Farmers use machines to spread seeds like wheat, canola, barley.
Germination
The development of a seed into a new plant.
http://studyjams.scholastic.com/studyjams/jams/science/plants/flowers.htm