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1 of 34© Boardworks Ltd 2011 Plant Hormones
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3 of 34© Boardworks Ltd 2011 What do plants need to grow? This plant hasn’t been looked after very well. What do plants need to grow healthily? sunlight water mineral nutrients If a plant cannot get these from its environment, can it move to somewhere else? Plants are rooted to one place. However, they can control their direction of growth. an air supply
4 of 34© Boardworks Ltd 2011 What controls plant growth? Plants grow in response to their environment. The shoots of these tulips grow upwards and the roots grow downwards. To what environmental factors do plants respond to make sure they grow properly? If a plant was unable to do this, it might not be able to get enough water or sunlight from its environment.
5 of 34© Boardworks Ltd 2011 What do plants respond to? Plants are very sensitive and their growth is affected by their environmental conditions. Any condition that affects plant growth is called a stimulus. lightwatergravity Which stimulus will have the strongest effect on the plant? What are three types of stimuli that plants respond to?
6 of 34© Boardworks Ltd 2011 Which stimulus?
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8 of 34© Boardworks Ltd 2011 A tropism is a growth movement in response to a stimulus. Plants grow towards or away from stimuli. A growth movement towards a stimulus is called a positive tropism. A growth movement away from a stimulus is called a negative tropism. What is a tropism? Will all the parts of a plant respond to a stimulus in the same way? What is growth away from a stimulus called?
9 of 34© Boardworks Ltd 2011 Plant responses to stimuli are given specific names: What do the names of each tropism mean? watergravitylight hydrotropismgeotropismphototropism Which parts of a plant respond to these different stimuli? Are there different types of tropisms?
10 of 34© Boardworks Ltd 2011 Defining tropisms
11 of 34© Boardworks Ltd 2011 How do tropisms affect growth? This plant does not have a very straight stem. What might have caused this? The shoots of plants grow towards sunlight. The plant was placed on a window sill and received light from one direction only. What is the name of this type of plant response? The response to sunlight is called phototropism.
12 of 34© Boardworks Ltd 2011 Phototropism experiment
13 of 34© Boardworks Ltd 2011 Do plants have hormones too? The growth of shoots and roots is controlled by a group of hormones called auxins. These chemicals are produced in the tips of the shoots and roots. Like humans, plants use hormones, (chemical messengers) to control their development. Hormones produced by plants control growth, flowering and fruit ripening. What environmental stimuli might cause a plant to produce auxins?
14 of 34© Boardworks Ltd 2011 Hormones and phototropism
15 of 34© Boardworks Ltd 2011 Discovery of auxins
16 of 34© Boardworks Ltd 2011 Which way up? How do plants always grow the right way up? Plants respond to gravity to grow in the right direction.
17 of 34© Boardworks Ltd 2011 Hormones and geotropism
18 of 34© Boardworks Ltd 2011 Roots always grow towards water, which is a positive tropism. Roots will grow sideways, or even upwards, towards water. Roots always have a stronger response to water than gravity to ensure that a plant gets the water it needs. How do roots respond to water?
19 of 34© Boardworks Ltd 2011 How do roots and shoots respond to stimuli? Shoots grow towards sunlight. They are positively phototropic. Plant stimuli affect certain parts of the plant in different ways. Shoots grow away from gravity. They are negatively geotropic. Roots grow away from sunlight. They are negatively phototropic. Roots grow towards gravity. They are positively geotropic. What experiments can be used to test these ideas?
20 of 34© Boardworks Ltd 2011 Tropisms and auxins – true or false?
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22 of 34© Boardworks Ltd 2011 growing cuttings killing weeds. controlling dormancy Why are these purposes useful for gardeners and farmers? Plant hormones are naturally-occurring chemicals, but they can also be produced synthetically for uses in gardening and agriculture, such as: How can plant hormones be used? making seedless fruit. ripening fruit
23 of 34© Boardworks Ltd 2011 A cutting is a part of plant that is removed from the main shoot. Do cuttings have everything they need to grow? How are cuttings grown? A cutting does not have roots and so has no supply of water or minerals. To stimulate root growth, cuttings are dipped into rooting powder. This contains plant growth hormones. Cuttings are genetically identical to the parent plant. This allows growers to copy successful plants.
24 of 34© Boardworks Ltd 2011 Growing plant cuttings
25 of 34© Boardworks Ltd 2011 Weeds are unwelcome plants that compete with the plants being grown by gardeners and farmers. How do plant hormones kill weeds? Plant hormones can be used instead to make weedkillers that only affect certain plants. However, many chemicals that are potential weedkillers are toxic to animals and humans, as well as plants. Most weeds have broad leaves. Cereals, which have narrow leaves, can be protected from weeds by using weedkillers that only effect the growth of broad-leaved plants.
26 of 34© Boardworks Ltd 2011 Fruit often has to travels thousands of miles from where it is picked to where it is sold in the shops. How are hormones used to ripen fruit? When the fruit reaches its destination, it can then be sprayed with artificial plant hormones to encourage ripening. Fruit is often picked before it is fully ripe. Why might this help keep the fruit edible? Unripe fruit is harder and less likely to bruise than ripe fruit when transported. Why might it be a good idea to wash fruit before eating it?
27 of 34© Boardworks Ltd 2011 Which hormone makes fruit ripen? Using artificial ethylene to ripen fruit is not just a modern practice. Ancient Egyptians exposed figs to natural gas, which contains ethylene, to encourage ripening. Ethylene is a plant hormone that controls fruit ripening. It can be sprayed on unripe fruit to speed up ripening. Why might it be important to keep fruit away from coal-burning engines during transportation? Some fruit, such as bananas, actually produce a large amount of ethylene, which can cause other nearby fruits to ripen.
28 of 34© Boardworks Ltd 2011 Controlling dormancy Seeds can lie dormant for many years. Dormant seeds don’t germinate, even in warm moist conditions. Dormancy is important as it ensures seeds don’t all germinate at the same time. This means that if there is a short period of poor growing conditions, such as a drought, some of the dormant seeds will survive. Dormancy is controlled by plant hormones. Farmers can add artificial hormones to seeds to prevent them from germinating. The record for the longest dormancy is held by a 1,300-year-old lotus seed which finally sprouted in 1995.
29 of 34© Boardworks Ltd 2011 Seedless fruit Plants usually reproduce using seeds found inside fruit, however people prefer to eat fruit without seeds. For some plants, farmers can produce seedless fruit by: Most plants only grow fruits if they have developing seeds. Plants that grow seedless fruit are often sprayed with plant hormones like auxin and giberellin to stimulate fruit growth, even though there are no seeds. preventing pollination selective breeding to create plants that have too many chromosomes, and so can’t produce seeds.
30 of 34© Boardworks Ltd 2011 Using hormones
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32 of 34© Boardworks Ltd 2011 Glossary
33 of 34© Boardworks Ltd 2011 Anagrams
34 of 34© Boardworks Ltd 2011 Multiple-choice quiz
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© Boardworks Ltd of 20 © Boardworks Ltd of 35 KS4 Biology Plant Responses.
Plant Responses Response to light Response to water Response to gravity Contents What do plants respond to? Using plant hormones Summary quiz.
Plant Hormones Tropisms Uses of plant hormones. How do plants always grow the right way up? What conditions will affect how a plant grows?
How are plants adapted to growth? Different parts of a plant are adapted to assist its growth and survival. Flowers are adapted to enable reproduction.
Plant Auxins Noadswood Science, Plant Auxins To understand how plant auxins function Thursday, August 20, 2015.
Title: Plants and tropisms 13 th March 2014 Learning question: How do plants use hormones to respond to stimuli? Homework: Study for homeostasis test on.
Tropic Responses Objectives: *Define geotropism and phototropism **Explain role of auxin in plant growth ***Explain the use of synthetic plant hormones.
Plants And things that plants get up to... KS3 Plants KS3 Sc1 Science Green plants as organisms 3) Pupils should be taught: that plants need carbon dioxide,
Objectives – What you will need to know from this section Study auxin as an example of a plant growth regulator under the headings of : H AUXINS.
Plant Hormones. Stimulus A change in organism’s environment.
Responses in Plants. Stimuli Plants respond to: Light Gravity Water Chemicals Touch Phototropism Geotropism Hydrotropism Chemotropism Thigmotropism.
GHS S3 Science. Learning objectives Define plant hormones Outline some of the effects of plant hormones Give examples of how they are used in food production.
Plant Hormones L.O: To understand how plants use hormones to respond to light, gravity and moisture.
22.5 Plant Hormones and Responses KEY CONCEPT Plant hormones guide plant growth and development.
Plant Responses Part 2: Plant Hormones. Review: What are plant responses? Called tropisms – When a plant responds to an outside stimulus What are some.
Plant hormones and Responses What is a hormone? A hormone is a chemical messenger produced in one part of an organism that stimulates or suppresses the.
Plant Hormones. Overview Plant cells, like animal cells, respond to the actions of a variety of chemical signals, called hormones Just like animal hormones.
Plant Hormones. Can you explain what is happening. Click to reveal the answer. Plant sensitivity The animation shows the growth of a young shoot towards.
Plant Hormones And Their Responses to Different Stimuli.
Responses to the Environment: PLANTS. Plant responses are also controlled by hormones. Significant hormones in plants are: 1)AUXINS = an important role.
Transport of Material in Plants. Internal Transport in Plants Small plants rely on simple diffusion or branching tubules to transport material throughout.
Plant Hormones and Responses KEY CONCEPT Plant hormones guide plant growth and development.
6.L.2.2 Explain how plants respond to external stimuli (including dormancy and forms of tropism) to enhance survival in an environment.
Plant Hormones. Can you explain what is happening. Click to reveal the answer. Plant sensitivity.
Nerve Impulses When nerves are resting, the inside of the nerve cell is negative, compared to the outside of the nerve cell When a nerve cell is transporting.
Plant Responses and Growth EQ: How do plants respond to stimuli and hormones?
Growth Control in Plants. Learning Objectives Explain how plant growth is controlled by hormones. Describe how these hormones can be used to change plant.
Lecture Seven Commercial use of plant hormones. Selective Weed killers Plant hormones can be extracted or artificial copies can be made. They can be used.
Plant Behaviors How Plants Respond to External Stimuli.
Plant Growth and Development. Types of Growth Apical meristem: plant tissue made of actively dividing cells. Primary growth and located at the tip of.
Plant Responses Chpt. 33. Stimulus and Response Stimulus: is anything that causes a reaction in an organism, or in any of its parts. Animal stimuli: -
1 of 9© Boardworks Ltd of 9© Boardworks Ltd 2009 Responses to environmental changes.
Aim: How do plants respond to changes in the environment?
Growth Control in Plants. Learning Objectives Explain tropisms—phototropism, geotropism/gravitropism and thigmotropism.
Green Plants as Organisms. Contents Photosynthesis Photosynthesis Photosynthesis vs. Respiration Photosynthesis vs. Respiration Plant Hormones Plant Hormones.
Plants depend on their immediate environment for the materials and energy they require for survival. Plants are relatively tolerant of environmental.
Hormonal regulation in plants Plants do not have a nervous system or endocrine system However they do produce hormones These hormones are produced by.
Plant Adaptation. Adaptation What environmental conditions must plants, animals and humans adapt to? means adjusting to specific environmental conditions.
Forces in Living Things. Forces Unbalanced forces cause motion Force in the form of pressure allows plants to stand upright When force is applied to an.
Plant Responses to Signals Chapter 39. Plants have to respond to gravity and other stimuli in environment. Growth pattern in plants - reaction to light.
7.2 Tropic responses. Plants grow towards or away from stimuli The growth response is called a tropism gravity light Shoots will grow towards light.
Pop-Quiz Define a negative feedback system Which organ produces the hormones that are used in regulation of blood glucose? Define Homeostasis?
Tropism 6 th Grade Science. Have you ever wondered how seedlings “know” which way to grow? The plant must send its roots down into the soil for minerals.
- Negative Tropism = To turn away from a stimulus + Positive Tropism = To turn towards a stimulus.
PLANT PROCESSES. ENERGY PROCESSING IN PLANTS Materials For Plant Processes To survive, plants need food, water, and oxygen. Roots absorb water which.
Tropisms. Plants cannot move from place to place. Usually they are held in position firmly by their roots. They can, however, orientate their stems and.
Plant Responses to Internal & External Signals Chapter 39.
Control of Plant Development. Plant growth regulators (PGRs) plant hormones that affect the rate of division, elongation and differentiation of plant.
Response to stimuli. 2 Contents Introduction Examples of responses Responses in the Flowering Plant Growth regulation Tropism Plant Growth Regulators.
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