Fertilisation and Germination

Like most living thing on this earth,  plants need water, oxygen, warmth and nutrients to grow and survive. Plants don’t need light when they are a seed. Only once they have sprouted their first leaf, do they take in light.

All the nutrients a seed needs are stored inside the seed.

A grain of pollen lands on a stigma.

If they are the correct species, it begins to grow a pollen tube down the style, until it reaches an ovule inside the ovary.

The nucleus of the pollen grain then travels down the pollen tube. The nucleus of the pollen grain joins with the nucleus of the ovule. This is called fertilisation.

After this the ovary develops into fruit and ovules become seeds.

These seeds have 3 important structures:

• Seed coat - Tough, protective covering
• Embryo - young root and shoot that will develop into the adult plant
• Food store - A store of food that the plant will use during development.

When the seed first begins to grow it is called Germination. A seed needs 3 things to germinate:

• Water - Seed swells up and the embryo starts growing
• Oxygen - Respiration and transferring energy
• Warmth - Speeds up chemical reactions and germination

Steps of Germination

1. The seed absorbs water rapidly and begins to swell. The hard coat splits

2. Root grows downwards

3. The shoot starts to grow upwards

4. First leaf starts to appear (plant begins to photosynthesis)

5. More leaves begin to appear and the plant continues to grow.

Quick Questions

1. List 3 things that almost all organisms need

2. Pollen lands on what part of the plant

3. What are the 3 parts of a seed

Order the images bellow

Questions

1. State the 3 requirements of a seed to germinate and explain how each assist the seed germinate

2. Draw a comic strip explaining all the steps involved in germination.

3. Copy and Complete the sentence

During ________ the nucleus of the ______ grain and the nucleus of the ________ join together. The ovary then develops into the _________, and the ovules become ________. To ________, the seed needs ________ water and oxygen.

4. Explain why a seed needs a food source?

5. Explain all the steps from the pollen leaving one plant, all the way to a seed germinating.