• Starter:
It is important to remove waste from the our bodies
Healthy kidneys help to keep our internal environment constant
Describe how a healthy kidney produces urine
• (5 marks)

• the kidney) filters the blood ignore refs to hormones and drugs
• (and then) reabsorbs all of the glucose
• reabsorbs some of the ions allow salts ignore minerals
• reabsorbs some of the water
• releases urea (in urine)
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Grade Objective
1-3
4-6
7-9
To be able to explain the role of plant hormones in agriculture and horticulture
Outcomes
To be able to state examples of plant hormones
To describe the uses of plant hormones in agriculture and horticulture
To explain how pant hormones work to improve agricultural and horticultural methods
Recap:
1. What is a tropism?
2. Can you describe the difference between positive and negative tropisms? Use an example in your answer
3. How do you think gardeners and farmers may utilise plant hormones?

We have already studied the effect of the hormone auxin on the growth of plant shoots and roots.
There are more hormones that are important in the growth and development of plants, we are going to learn about:
• Gibberellins
• Ethene

Task: Watch the video and answer the following questions: https://www.youtube.com/watch?v=EZ5tU45Ti_g
1. If the end of the shoot is cut off, what effect does this have on the growth of the plant? Why?
2. What effect does covering the tips of plants have on the growth of the plant? Explain your answer.
3. What is the name of the hormone which works alongside auxins?
4. What is the role of gibberellins during germination?
5. What other roles do gibberellins play in a plants development?

1. If the end of the shoot is cut off then there is no more auxin produced, as auxin is made in the tip of the
shoot. This causes the shoot to stop growing.
1. If the tip of the plant shoot is covered from the light, this will mean that there won’t be a lit/shaded side of the shoot. Therefore auxin is not broken down and
phototropism cannot occur.
1. Cytokines work alongside auxins.
1. During germination gibberellins break down starch into
sugars, this provides the seed with energy to grow
5. Gibberellins stimulate flowering and the production of
fruit, they also work with auxins to cause cell elongation.

Think > Pair > Share:
Now you know the role of auxins and gibberellins in plant growth & development, come up with some ways in which gardeners or famers may use these hormones.

• https://www.youtube.com/watch?v=TTLgTIip mA8&t=90s

Task: You have been asked by Gardener´s
World Magazine to highlight the benefits of using artificial plant hormones.
You can comment on how they can be used to destroy weeds ; growing cuttings of your favourite plant; ensure all fruits ripen at the same time.
What they’re looking for …
• Demonstrating you have an understanding of the role hormones play in plants. You can include detail of the use of auxins and how commercially they are used to kill weeds.
• Discuss the benefits of using hormones
• Provide examples of commercial hormones and the crops they are used on
Use diagrams to help make your point

Auxins
Cereal crops and grasses are usually narrow-leaved plants, in comparison to weeds which are usually broad-leaved plants. When weed killer is sprayed onto crops it mostly lands on the leaves, therefore plants with a higher surface area will absorb more weed killer. The weeds will therefore absorb more the weed killer and the crops plants remain mostly unaffected. These are known as selective herbicides.
Auxins can also be used in tissue culture during the cloning process.
They stimulate growth and cell division in order to produce identical plants for the farmers.
Giberrellins
The advantages of this hormones are vast and it has been utilised in a number of ways. One important use is in controlling seed dormancy, gibberellins are used to end dormancy in order to speed up seed germination. They are used to promote the flowering of many plants throughout the year. They are also widely sued to increase the size of fruit, commercial fruit growers spray seedless fruits with gibberellins in order to promote growth.
Ethene
Ethene (or ethylene) is widely used to promote the ripening of fruit.
Fruit is usually harvested when it is not ripe, it is then transported in a chilled environment to a storage unit. Warmer temperatures and ethene added to the atmosphere then slowly ripens the fruit for when it is needed.

1. Gibberellins are needed to ripen fruit
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2. Auxins can be used on cuttings as a hormone rooting powder
3. Positive phototropism is when shoots grow towards the light
4. In shoots, auxins accumulate on the side of the shoot which is in the light.
5. Positive gravitropism is when roots grow away from gravity
6. Gibberellins are used to promote flowering and the production of fruit.
7. Fruit can be placed in a chilled environment in order to speed up the ripening process

• Practical