Week 1 - Sexual reproduction in plants

This week we are beginning our work on reproduction.  As we know, all living organisms reproduce to produce the next generation and ensure that the species does not become extinct. To produce offspring which are different from their parent/s, allowing for variation to occur, many plants and animals reproduce sexually. This means that a male cell must combine with a female cell to produce a fertilised egg which then develops into a new plant or animal. Today we are going to look in detail at how this happens in flowering plants. In class we will be directing a flower to understand the role of each part of the flower.

Please watch the video below:

As you have heard, pollen is the male sex cell of flowering plants and ovules are the female sex cells. When the pollen is transferred from one flower to another, we call this pollination. If the pollen comes from the same flower as the ovules being pollenated we call this self-pollination. If the pollen comes from a different plant, we call this cross-pollination. This can happen in a number of different ways. Sometimes insects or animals carry pollen from flower to flower as they visit them. The wind is also used to pollinate plants such as trees and grasses. It is this type of pollen you might be allergic to if you suffer from hay-fever.

Below is a video describing the process of pollination.

Once the male pollen has been stuck to the stigma, the pollen cell can begin to travel down the pollen tube inside the style until it reaches the ovules and joins with one of them. This process is called fertilisation. Again, the video below explains this part of the process in more detail.

Once fertilisation has occurred then the fertilised ovule begins to develop into a seed which will grow into a new plant. 

Now we are going to dissect a flower to see if we can identify any of the separate reproductive parts of the flower. The video below shows one I did earlier. 

If you have access to a flower, have a go at dissecting it, drawing each separate part and describing what the function of each part is. If not, please complete the sheet below.

The process of producing flowers and then seeds uses lots of the plants energy. Colourful flowers are usually pollinated by animals but small green flowers like those of grasses often use wind pollination.