Practical Biology

A collection of experiments that demonstrate biological concepts and processes.

geranium leaf starch experiment

Observing earthworm locomotion

geranium leaf starch experiment

Practical Work for Learning

geranium leaf starch experiment

Published experiments

Testing leaves for starch: the technique, demonstration or class practical.

This procedure kills a leaf, disrupts the cell membranes and softens the cuticle and cell walls. This makes it possible to extract the chlorophyll with hot ethanol and also allows the iodine solution to penetrate the cells and react with any starch present.

Lesson organisation

You can run this as a teacher demonstration, or with students carrying out the procedure in pairs.

Apparatus and Chemicals

For each group of students:.

Eye protection

Beaker for boiling water, 250 cm 3

Boiling tube, 1 for each type of leaf used

Anti-bumping granules (optional)

For the class – set up by technician/ teacher:

Ethanol (IDA) ( Note 1 )

Kettles of boiling water ( Note 2 )

OR Electric water baths set at 90 °C containing a boiling tube rack

Iodine in potassium iodide, solution in dropper bottles ( Note 3 )

Beaker or jar (at least 250 cm 3 ), labelled ‘Waste ethanol’ ( Note 4 )

Leaves, different types, such as pelargonium (pot geranium) ( Note 5 )

Health & Safety and Technical notes

Ethanol (IDA), iodine solution and hot liquids require safety precautions to be taken. Wear eye protection.

Read our standard health & safety guidance

1 Ethanol (IDA) – refer to CLEAPSS Hazcard 40A and student safety sheet 60 – is highly flammable (flash point 13 °C) and harmful (because of the presence of methanol). The risks in this procedure are reduced by using hot water from kettles or in water baths rather than heating with a Bunsen burner flame. Some protocols recommend propanol (Hazcard 84A) in place of ethanol, as it removes chlorophyll more effectively. However, it has the additional risk of eye damage, its flashpoint is very similar to that of ethanol (IDA), and it may be more expensive.

2 Kettles are a safer source of hot water than heating with a Bunsen burner because of the presence of flammable ethanol (IDA) in this procedure. Students are familiar with the hazards of using kettles. Consider how to limit the movement of students around the laboratory with kettles or beakers of near-boiling water. Electrically-heated and thermostatically-controlled hot water baths may be a safer alternative.

3 Iodine solution – refer to CLEAPSS Hazcard 54B and Recipe card 39. A 0.01M solution is suitable for starch testing. Make this by 10-fold dilution of 0.1M solution. Once made, the solution is a low hazard but may stain skin or clothing if spilled, and may irritate the eyes.

4 Save the waste ethanol as a source of chlorophyll for future work. Make sure it cannot be tipped over and is in a safe place so it is not a fire hazard.

5 If the teacher or technician snips the leaves from the plants to give to the students, the plants are more likely to survive to be used again. Variegated Pelargonium (pot geranium) are good subjects for this experiment as are Tradescantia and Impatiens (busy lizzie).

6 Ensure that the plants have been well-illuminated for 24-48 hours. In winter, it might be worth using a halogen lamp to ensure the illumination is adequate.

Ethical issues

There are no ethical issues associated with this procedure.

SAFETY: Ensure the ethanol is kept away from naked flames. Students should wear eye protection when working with ethanol or iodine solution. Take care with hot liquids. Be aware that plant sap may irritate the skin.

Investigation a Collect leaves from the plants to be tested.

Use forceps to hold the leaf in a beaker of boiling water to kill it

Science Fair Projects for 8th Graders

Science Fair Projects for 8th Graders As kids reach the 8th grade, their exposure to science goes up a notch. Equipped with basic knowledge, they can begin to explore more complicated concepts and satisfy their curiosity for deeper answers to the 'whys' and 'hows' of...

Science Fair Projects for 7th Graders

Science Fair Projects for 7th Graders

Science Fair Projects for 7th Graders​​ Science fair projects for 7th graders are a step up in complexity. Because 7th graders have a better grasp of science concepts, they’re expected to practice the scientific method in the way they approach their experiments–which...

Home Science Experiments for Preschoolers

Home Science Experiments for Preschoolers

Home Science Experiments for Preschoolers Home science experiments for preschoolers are a great way to pique your child’s curiosity, teach them valuable knowledge, and allow them to have some fun in the comfort of their own home. There are plenty of activities your...

Easy Science Fair Projects for Kids

Easy Science Fair Projects for Kids

Easy Science Fair Projects for Kids Science fairs are a long-standing tradition that provide kids with the opportunity to better understand practical concepts in fun and innovative ways. The great thing about the experiments presented at these events is that they...

How to Make a Pollinator Hotel

How to Make a Pollinator Hotel

Have you ever wondered how you can help provide habitat for pollinators like honey bees and butterflies in your back yard? Learn how to make a pollinator hotel with this step-by-step guide and lesson. Pollinators are animals that help move pollen. Most pollinators are...

JOIN OUR COMMUNITY

Get project ideas and special offers delivered to your inbox.

should I learn computer coding

Experiments to show the factors required in photosynthesis (2) - light and carbon dioxide

Destarching the plant:, treatments a the effect of light, b the effect of carbon dioxide.

The plant must be kept well watered and exposed to good light. After a couple of days or more, the leaves are removed for testing. It may be useful to mark them with cuts to identify them later.

Testing a leaf for starch Decolourising the leaf

Procedure after decolourisation - testing for the presence of starch.

Immerse the whole leaf briefly in cold water - tap water will do.

Spread out the leaf in a plastic (Petri) dish.

Add a few drops of iodine solution (I/KI), and wait a few minutes for colour to develop.

Grey- blue -black areas represent starch (e.g. B2 above).

Yellow- orangey -red areas represent no starch (e.g. B1 above).

                                       

Practical Science

Table of Contents

geranium leaf starch experiment

Exploring Photosynthesis Variables: A Comprehensive Leaf Starch Test Experiment

Introduction:.

Delve into the fascinating world of plant biology with this comprehensive practical experiment, designed to test the effects of different variables on the rate of photosynthesis in leaves. Photosynthesis, the process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen, is vital to life on Earth. By modifying variables such as light exposure and carbon dioxide availability, we can observe how these factors impact starch production in leaves and gain a deeper understanding of the factors that influence photosynthesis. Uncover the intricacies of plant life and the essential role that photosynthesis plays in the balance of our ecosystem.

Materials and Equipment:

  • Fresh green leaves from a plant exposed to sunlight for several hours (Geraniums work best)
  • Aluminum foil
  • Calcium oxide (quicklime)
  • Test tube or boiling tube
  • Forceps or tweezers
  • Bunsen burner or hot plate
  • Ethanol (alcohol)
  • Iodine solution
  • White tile or ceramic plate
  • Safety goggles
  • Lab coat or apron

Step-by-Step Method:

  • Safety first: Put on your safety goggles and lab coat or apron to protect your eyes and clothing from potential spills.
  • Choose a healthy green leaf from a plant that has been exposed to sunlight for several hours, ensuring the leaf has had ample time to undergo photosynthesis.
  • Modify the variables: a. Light exposure: Cover a portion of the leaf with aluminum foil, blocking sunlight from that area and preventing photosynthesis. b. Carbon dioxide availability: Place the plant in a container filled with calcium oxide (quicklime) to absorb carbon dioxide, thereby limiting the plant’s access to this essential component of photosynthesis.
  • Leave the plant under these modified conditions for a few hours.
  • Boil a beaker of water on a Bunsen burner or hot plate. Use the forceps or tweezers to hold the leaf and immerse it in the boiling water for approximately 1-2 minutes. This step will soften the leaf and kill the cells, halting further photosynthesis.
  • Carefully remove the leaf from the boiling water using the forceps or tweezers, and then immerse it in a test tube or boiling tube filled with ethanol (alcohol). Ensure the leaf is fully submerged.
  • Place the test tube or boiling tube containing the leaf and ethanol in the beaker of hot water. The ethanol will heat up and decolorize the leaf, removing its chlorophyll. This process should take around 5 minutes. Note: Ethanol is highly flammable, so ensure there are no open flames nearby.
  • Once the leaf is decolorized, carefully remove it from the ethanol using forceps or tweezers, and rinse it with cold water to remove any residual ethanol.
  • Place the leaf on a white tile or ceramic plate, and add a few drops of iodine solution. The iodine will react with any starch present in the leaf, turning it a blue-black color.
  • Observe the leaf for any blue-black coloration, which indicates the presence of starch. Compare the areas of the leaf that were exposed to different variables.

Safety and Troubleshooting:

  • Always wear safety goggles and a lab coat or apron to protect your eyes and clothing from potential spills.
  • Use caution when handling hot equipment and liquids to avoid burns.
  • Ethanol is highly flammable, so ensure there are no open flames nearby when heating the ethanol.

Test Questions:

  • What are the two variables being tested in this experiment, and how are they modified?
  • Why is it important to cover a portion of the leaf with aluminum foil during this experiment?
  • How does calcium oxide affect the rate of photosynthesis in the plant?
  • What conclusions can you draw from the blue-black coloration observed in different parts of the leaf?
  • Why is it important to study the effects of different variables on the rate of photosynthesis?

Answer Key:

  • The two variables being tested in this experiment are light exposure and carbon dioxide availability. Light exposure is modified by covering a portion of the leaf with aluminum foil, and carbon dioxide availability is altered by placing the plant in a container filled with calcium oxide.
  • Covering a portion of the leaf with aluminum foil is important because it blocks sunlight from that area, preventing photosynthesis from occurring and allowing us to observe the effects of light exposure on starch production.
  • Calcium oxide absorbs carbon dioxide, limiting the plant’s access to this essential component of photosynthesis, and thus affecting the rate of photosynthesis in the plant.
  • The blue-black coloration observed in different parts of the leaf indicates the presence of starch, which is a product of photosynthesis. Comparing the coloration in areas exposed to different variables helps us understand how these factors impact the rate of photosynthesis and starch production.
  • Studying the effects of different variables on the rate of photosynthesis is important because it helps us understand how environmental factors can influence plant growth and productivity, which has implications for agriculture, ecosystems, and climate change.

By conducting this practical experiment, students can gain valuable insights into the factors that affect photosynthesis and explore the significance of these variables in plant biology. This hands-on approach encourages curiosity and appreciation for the natural world while reinforcing key scientific concepts.

Discovering Photosynthesis: Testing a Leaf for Starch – A Hands-On Practical Experiment

Share this:

  • Click to share on Twitter (Opens in new window)
  • Click to share on Facebook (Opens in new window)
  • Click to print (Opens in new window)
  • Click to email a link to a friend (Opens in new window)

Type your email…

' src=

  • Already have a WordPress.com account? Log in now.
  • Subscribe Subscribed
  • Copy shortlink
  • Report this content
  • View post in Reader
  • Manage subscriptions
  • Collapse this bar

School Science/Testing leaves for starch

Testing leaves for starch

  • 2 Equipment
  • 3 Safety precautions

Introduction

In a food chain, plants are usually the producers, which means they can make food by themselves. They make food by carrying out photosynthesis, then storing the food made in the form of starch.

The aim of the experiment is to compare a covered part of a leaf to an uncovered part of a leaf to see whether plants produce starch

  • Water 200 ml
  • Boiling water any amount that doesn't exceed 600 ml
  • Ethanol 5 ml
  • Iodine solution 3 drops
  • Safety Goggles
  • Bunsen burner
  • forceps or tweezers

Safety precautions

  • Wear safety goggles
  • Keep ethanol away from Bunsen burner; ethanol is flammable
  • Tie the hair back
  • Tuck ties, files and loose material away
  • Keep all bags out of the way to avoid tripping up.
  • Make sure you are not wearing tight clothes
  • Use the forceps to place the leaf in the boiling water
  • Arrange the apparatus as shown in the figure.
  • Place a beaker of hot water in the hot water bath. When the water has boiled add the leaf that had been in light.
  • Wait 3 minutes for the leaf to boil (this is to get rid of the waterproof layer and break the open cells and make it soft).
  • Take out the leaf using the forceps.
  • soak it in the ethanol and the water.
  • Put the leaf in a boiling tube and cover with ethanol.
  • Put the tube of ethanol plus leaf into the beaker of hot water WITHOUT the bunsen burner on as ethanol is highly flammable.
  • Dip the leaf back into the hot water, using the forceps.This is done to get the ethanol off the leaf.
  • Spread the leaf out on the tile using the glass rod. Add about five drops of iodine solution on to the leaf and observe.
  • Carefully draw a diagram of the leaf marking any areas that have stained black.

From this experiment, you will discover that leaves contain starch in the black parts of the leaf. But originally where the green parts of the leaf were present starch is available in lesser quantity..

geranium leaf starch experiment

  • Book:School Science

Navigation menu

Microbe Notes

Microbe Notes

Leaf Starch Test: Principle, Procedure, Results, Uses

Starch in a leaf can be easily detected in a lab with the help of iodine solution. This test is called the ‘Leaf Starch Test’ or ‘Iodine Test for Starch’.

Green leaves are the food factory of plants. Green leaves have abundant chloroplasts – special organelles where the photosynthesis process takes place – so, a large portion of photosynthesis occurs in the leaves of a plant. The glucose produced during photosynthesis is stored as an energy reserve in the form of starch in the leaf, stem, branches, roots, and fruits of a plant. Starch is one of the abundant natural carbohydrates consumed in the diet by humans and other animals as an energy source.

Starch is a complex polymeric carbohydrate (polysaccharide) stored as a reserve food material in plants. It is formed of glucose monomers joined together by a glycosidic bond. The glucose units exist in two forms in natural starch; amylose and amylopectin . Amylose is water insoluble straight-chain polymer of D-glucose subunits linked together by α-1,4 glycosidic bond. Amylopectin is a water-soluble branched chain polymer of D-glucose subunits linked together by α-1,6 glycosidic bond.

Table of Contents

Interesting Science Videos

Objectives of Leaf Starch Test

  • To detect the presence of starch in a leaf
  • To assess the extent of photosynthesis occurring in the leaf

Principle of Leaf Starch Test

Iodine is insoluble in water; but when potassium iodide is added, it dissociates into K + and I -, and the resulting I – reacts with molecular iodine (I 2 ) to form a triiodide complex (I 3 – ). The triiodide complex can further associate with molecular iodine and form pentaiodide complex (I 5 – ) and so on.

Principle of Leaf Starch Test

The amylose component of starch is arranged in the form of helical coils. When the iodine-iodide solution is added over starch molecules, the negatively charged polyiodide (mainly triiodide, I 3 – ) slips inside the helices of the amylose chain forming a charge transfer complex. Electrons in this charge transfer complex absorb light energy and get excited. This phenomenon is perceived by the human eye as intense blue-black color.

Hence, in the presence of starch, a blue-black colored complex is formed when the iodine-iodide solution is added over the starch. The intensity of the blue-black color is proportional to the quantity of amylose (or starch) but doesn’t give an exact quantitative (concentration) value. Hence, the test is a qualitative type test.

Requirements for Leaf Starch Test

Beaker
Petri plate
Test tube
Burner
Dropper
Forceps
Water
Ethanol
Lugol’s Iodine Solution
Freshly plucked leaf
(green leaf of an outdoor plant)

Procedure of Leaf Starch Test

  • Pluck a green leaf of any outdoor plant. A medium size leaf, preferably, a leaf recently exposed to sunlight is better for this test. 
  • Boil about 250 mL water in a beaker and put the leaf in the beaker and let it boil for a few minutes (2 to 5 minutes) till its waxy coat got off and it gets soft.
  • Using forceps, take out the leaf and spread it on a petri plate. 
  • Place the leaf in a test tube and pour ethanol (90% or more v/v) till the leaf submerses. 
  • Place the test tube in the beaker with boiling water (or in a water bath) and let the ethanol boil till the leaf decolorizes. Take out the leaf after 5 to 10 minutes if it doesn’t decolorize completely. 
  • Place the leaf on a petri plate and spread it properly and rinse with cold water. 
  • Using a dropper, add a few drops of iodine solution over the leaf to cover it. 
  • Examine the color of the leaf after 2 minutes of the addition of iodine solution.

Leaf Starch Test

Observation of Leaf Starch Test

  • The leaf will decolorize and become whitish after boiling in an ethanol solution. 
  • The leaf will turn dark blue-black color after the addition of iodine solution. 

Result and Interpretation of Leaf Starch Test

The development of a blue-black color over the surface of the leaf indicates the presence of starch in the leaf. It suggests that the leaf was undergoing a photosynthesis process and had starch within it. 

Precautions

  • Use forceps to place a leaf in and out of the boiling water and ethanol solution. 
  • Always use green leaves exposed to sunlight for better results. 
  • Do not direct the mouth of the test tube with ethanol towards your face while boiling it. 

Uses of Leaf Starch Test

  • In the assessment of the photosynthetic activity in leaves.
  • It is used to study photosynthesis patterns, starch accumulation, and depletion patterns in leaves, and assessment of environmental factors influencing photosynthesis and starch accumulation. 
  • It is used as a teaching tool for basic-level students to introduce them photosynthesis process in leaves and carbohydrate storage. 

Limitations of Leaf Starch Test

  • It is a qualitative test and hence only indicates the presence or absence of starch but doesn’t represent the quantity of starch present. 
  • This test can be easily influenced by exposure of the leaf to sunlight, condition of the leaf, and quality and quantity of iodine solution. 
  • https://www.bbc.co.uk/bitesize/guides/zpcvbk7/revision/3
  • https://practicalbiology.org/standard-techniques/testing-leaves-for-starch-the-technique
  • https://www.wikihow.com/Test-for-Starch
  • https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_(Biological_Chemistry)/Carbohydrates/Case_Studies/Starch_and_Iodine
  • https://www.biologyonline.com/dictionary/iodine-test
  • https://microbiologynote.com/iodine-test/
  • https://learning-center.homesciencetools.com/article/test-for-starch-photosynthesis/
  • https://science.cleapss.org.uk/resource-info/pp088-testing-leaves-for-starch.aspx

About Author

Photo of author

Prashant Dahal

3 thoughts on “Leaf Starch Test: Principle, Procedure, Results, Uses”

thanks very much for your clear notes

Wow it is so very good

This site is so helpful. Thank you a million

Leave a Comment Cancel reply

Save my name, email, and website in this browser for the next time I comment.

Photosynthesis: testing a variegated leaf for starch

  • Share to Facebook
  • Share to Twitter
  • Share via Email

Age Ranges:

This resource tackles the learning objective “Only areas of the plant with chloroplasts can make starch in photosynthesis”. This is activity 11 in the ‘Photosynthesis: A Survival Guide’ scheme and follows up from activity 10, ‘What are chloroplasts’.

Students carry out a starch test on a variegated leaf to demonstrate that only the parts containing chloroplasts are able to synthesise starch.

This resource is designed for 11-14 pupils but could be extended for use with older students as appropriate.

For a fun activity for an open evening or a science day, you can prepare ‘secret messages’ or hidden images on all-green pelargonium leaves for students to reveal by testing for starch, as shown in the video below.

You may wish to use  this video clip , showing 19th century scientist Julius von Sachs’ pioneering research into how plants form starch from the BBC’s ‘Botany: A Blooming History series, available from the SAPS website.

geranium leaf starch experiment

What's included?

  • SAPS - PSG11 - Which part of a leaf produces starch - teacher notes
  • SAPS - PSG11 - Which part of a leaf produces starch
  • SAPS - PSG11 - Which part of a leaf produces starch - student notes
  • Photosynthesis

Related content

Teaching resources.

  • Using Pelargoniums (Geraniums) in the Lab
  • Sugar, starch or cellulose? What carbohydrates do plants make?
  • Video clip - Light and starch production
  • Photosynthesis: what are chloroplasts?

Practical: Investigating Photosynthesis ( Edexcel IGCSE Biology )

Revision note.

Lára

Biology Lead

Practical: Evolution of Oxygen

  • We can demonstrate the evolution of oxygen (from the process of photosynthesis) using water plants such as   Elodea or Cabomba - types of pondweed
  • As photosynthesis occurs, oxygen gas produced is released 
  • As the plant is in water, the oxygen released can be seen as bubbles leaving the cut end of the pondweed
  • Boiling tube
  • Bunsen burner (for the oxygen test)
  • Heat proof mat
  • Take a bundle of shoots of a type of pondweed
  • Submerge them in a beaker of water underneath an upturned funnel
  • Fill a boiling tube with water and place it over the end of the funnel
  • As oxygen is produced, the bubbles of gas will collect in the boiling tube and displace the water

Results and analysis

  • Show that the gas collected is oxygen by relighting a glowing splint
  • The quantity of bubbles / volume of oxygen can also be measured in order to investigate the rate of photosynthesis over a certain amount of time

Evolution of Oxygen Practical

Experiment to show the evolution of oxygen from a water plant

Practical: Investigating Light & Photosynthesis

  • Although plants synthesise glucose during photosynthesis, their leaves cannot be tested for its presence as the glucose produced is quickly used up, converted into other substances and transported or stored as starch
  • Starch is stored in the chloroplasts where photosynthesis occurs so testing a leaf for starch is a reliable indicator of which parts of the leaf are photosynthesising
  • Leaf tissue
  • Bunsen burner
  • Gauze platform
  • Safety goggles
  • Iodine solution

Investigating the requirement for light in photosynthesis

  • Before testing for starch, complete the following procedure:

Method Part 1 - Preparing the leaf to be tested

  • This ensures that any starch already present in the leaves will be used up and will not affect the results of the experiment
  • Following de-starching, partially cover a leaf of the plant with aluminium foil and place the plant in sunlight for a day
  • Remove the covered leaf and test for starch using the method below

Method Part 2 - Testing the leaf for starch

  • This kills the tissue and breaks down the cell walls
  • This removes the chlorophyll so colour changes from iodine can be seen more clearly
  • This is done to soften the leaf tissue after being in ethanol
  • Spread the leaf out on a white tile and cover it with iodine solution

Testing a variegated leaf for starch

Testing a leaf for starch

  • In a green leaf, the entire leaf will turn blue-black as photosynthesis is occurring in all areas of the leaf
  • When the cells can't photosynthesise they break down the starch to use the glucose for respiration
  • This proves that light is necessary for photosynthesis and the production of starch

Light and photosynthesis

Photosynthesis cannot occur in sections of the leaf where light cannot reach the chloroplasts

  • In the experiment example shown above, after testing for starch the majority of the leaf would appear blue-black, however there would be a strip of orange-brown with a blue-black triangle in the centre
  • Care must be taken when carrying out this practical as ethanol is extremely flammable, so at that stage of the experiment, the Bunsen burner should be turned off
  • The safest way to heat the ethanol is in an electric water bath rather than using a beaker over a Bunsen burner with an open flame

Applying CORMS evaluation to practical work

  • When working with practical investigations, remember to consider your CORMS evaluation

CORMS evaluation

CORMS evaluation

  • C - We are changing whether there is light or no light onto the leaf
  • O - The leaves will be taken from the same plant or same species, age and size of the plant
  • R - We will repeat the investigation several times to ensure our results are reliable
  • M1 - We will observe the colour change of the leaf when iodine is applied
  • M2 - ...after 1 day
  • S - We will control the temperature of the room

Remember that when using CORMS you must make sure to use the word same when stating your Organism e.g. same species. Then you have to pick a different factor for your Same part of the answer. There are often two marks available for listing two different control variables for the Same part of the answer. 

Practical: Investigating Carbon Dioxide & Photosynthesis

  • The iodine test for starch can be used to investigate the requirement for carbon dioxide in photosynthesis
  • Conical flasks
  • Potassium hydroxide solution
  • Clamp stands
  • The potassium hydroxide will absorb carbon dioxide from the surrounding air
  • Enclose another leaf with a conical flask containing no potassium hydroxide (control experiment)
  • Place the plant in bright light for several hours
  • Drop the leaf in boiling water
  • Transfer the leaf into hot ethanol in a boiling tube for 5-10 minutes
  • Rinse the leaf in cold water

Sunlight and photosynthesis

Experiment to test if carbon dioxide is needed for photosynthesis

  • The leaf from the conical flask containing potassium hydroxide will remain orange-brown as it could not photosynthesise due to lack of carbon dioxide
  • The leaf from the control conical flask not containing potassium hydroxide should turn blue-black as it had all necessary requirements for photosynthesis
  • C - We are changing whether there is carbon dioxide or no carbon dioxide
  • O - The leaves will be taken from the same plant or same species, age and size of plant
  • S - We will control the temperature of the room and the light intensity

Practical: Investigating Chlorophyll and Photosynthesis

  • Starch is stored in chloroplasts where photosynthesis occurs so testing a leaf for starch is a reliable indicator of which parts of the leaf are photosynthesising
  • This method can also be used to test whether chlorophyll is needed for photosynthesis by using a variegated leaf (one that is partially green and partially white)
  • Leaf tissue (leaves must be variegated )
  • The white areas of the leaf contain no chlorophyll and when the leaf is tested only the areas that contain chlorophyll stain blue-black
  • The areas that had no chlorophyll remain orange-brown as no photosynthesis is occurring here and so no starch is stored
  • C - We are changing whether there is chlorophyll or no chlorophyll

Don't forget that CORMS questions in your exams will likely ask about unfamiliar experiments so you need to practice applying CORMS to lots of different practical scenarios. 

You've read 0 of your 10 free revision notes

Unlock more, it's free, join the 100,000 + students that ❤️ save my exams.

the (exam) results speak for themselves:

Did this page help you?

  • Respiration
  • Gas Exchange
  • Transport Systems
  • Co-ordination & Response
  • Reproduction
  • Inheritance
  • The Organism in the Environment
  • Feeding Relationships

Author: Lára

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

  • International
  • Education Jobs
  • Schools directory
  • Resources Education Jobs Schools directory News Search

GCSE Testing a Leaf for Starch

GCSE Testing a Leaf for Starch

Subject: Biology

Age range: 14-16

Resource type: Lesson (complete)

froycroft

Last updated

23 September 2021

  • Share through email
  • Share through twitter
  • Share through linkedin
  • Share through facebook
  • Share through pinterest

geranium leaf starch experiment

A lesson based around the practical for testing for starch in a geranium leaf.

Includes a reliable method

Technical notes This works really well if it is prepared correctly - the plants must be de-starched in the dark for at least 2 days and then illuminated under bright light for about a day before the lesson. In the lesson before this, the students could have made and attached their own card templates (can be done before or after the plant is de-starched).

Creative Commons "Sharealike"

Your rating is required to reflect your happiness.

It's good to leave some feedback.

Something went wrong, please try again later.

This resource hasn't been reviewed yet

To ensure quality for our reviews, only customers who have downloaded this resource can review it

Report this resource to let us know if it violates our terms and conditions. Our customer service team will review your report and will be in touch.

Not quite what you were looking for? Search by keyword to find the right resource:

Science Technician Community

  • Search forums

Follow along with the video below to see how to install our site as a web app on your home screen.

Note: This feature currently requires accessing the site using the built-in Safari browser.

  • Science Area
  • Supporting Biology

starch in leaves

  • Thread starter Christine Broadbent
  • Start date Mar 21, 2017

Christine Broadbent

Christine Broadbent

Magic maiden.

  • Mar 21, 2017

Hi, I've only ever used geranium leaves for this experiment, but we only have two small plants in school and it's the wrong time of year to get them elsewhere!! Are there any other types which will work as well? Would waxy leaves i.e. laurel/rhododendron work? Thanks.  

Paul Murphy

Try primroses. Waxy leaves will not work.  

Muttley

Spider plant works too.  

Spider plants store sugar rather than starch, if I remember correctly.  

Shazz

Christine Broadbent said: Hi, I've only ever used geranium leaves for this experiment, but we only have two small plants in school and it's the wrong time of year to get them elsewhere!! Are there any other types which will work as well? Would waxy leaves i.e. laurel/rhododendron work? Thanks. Click to expand...
  • Mar 22, 2017

GeorgetheScienceTech

GeorgetheScienceTech

Sharon Watson said: Out of interest I've just had a go with a spider plant leaf and it doesn't work - bit too tough. How about dandelion leaves - I have quite a few in my lawn!! Click to expand...
  • Mar 23, 2017

Sorry, I meant tradescantia with the green and white leaves. We were caught on the hop this morning with a late request and found a bush with variegated leaves but the teacher complained they were too waxy. Serves her right...  

  • Mar 29, 2017

We've found variegated ivy leaves work well. Nice thorough boil to start with to soften the leaves, then soak them in warm ethanol for a while (as long as time allows, refreshing the ethanol halfway through helps) before finally adding she drops of iodine.  

  • Mar 30, 2017

When I first started in my current post we did testing the leaf for starch without success. When I had to purchase ethanol I followed the previous senior tech's list with some editing. I noticed that he bought absolute ethanol at a large price and I decided to buy IMS at a greatly reduced cost. Lo and behold the test worked, we came to the conclusion that the absolute ethanol not only stripped the chlorophyll from the cells but the starch as well.  

  • Mar 31, 2017

I did this prac yesterday and it worked OK. Not amazing, but OK. Used geraniums and put black paper masks on some of the leaves Monday morning. In hindsight as last weekend was so lovely up here I wish I had put the masks on on Friday, but I didn't get round to it. Tried with one of the (what I think is a) spider plant (the long thin leaves that are green down the middle and white on the sides) but that didn't work, as other have said, it was 'too waxy' I think.  

Spider plants store energy as sugar not starch so it wouldn't work anyway....  

Kayleigh

We used gerniumus. I put one in a cupboard for 3 days before particle and it worked brilliant, then just picked a random one from the greenhouse- its on the roof so perfect conditions for light. teachers were amazed at hoe well it worked this year.  

Trish Marlow

  • Apr 3, 2017
  • Apr 10, 2017

Thanks everyone. We tried pansies and primrose leaves. some worked, some didn't. We put it down to pupil error!  

Christine Broadbent said: Thanks everyone. We tried pansies and primrose leaves. some worked, some didn't. We put it down to pupil error! Click to expand...
  • This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. By continuing to use this site, you are consenting to our use of cookies. Accept Learn more…

COMMENTS

  1. Testing leaves for starch: the technique

    Investigation. a Collect leaves from the plants to be tested. b At your desk, pour some boiling water from a kettle into a large beaker. c Using forceps, pick up one of your leaves and hold it in the hot water for about one minute. d Using forceps, remove the leaf from the boiling water and note how it has changed.

  2. Photosynthesis- Geranium Leaves and Starch Detection

    This video, produced by W. David West, PhD, at Oakland Community College in the Summer of 2020, demonstrates how starch, produced by photosynthesis in Gera...

  3. Starch Test for Plants

    Place the beaker or jar in a saucepan full of water. 5. Heat the pan until the ethyl alcohol begins to boil. 6. Remove from the heat. 7. Dip each of the leaves in the hot water for 60 seconds, using tweezers. 8. Drop the leaves in the beaker or jar of ethyl alcohol for two minutes (or until they turn almost white).

  4. Experiments to show factors required by Photosynthesis

    These experiments start with destarched potted plants - Geranium (Pelargonium) is often used. These are then subjected to various treatments, left in the light for a few days then subjected to decolourising procedures and then finally tested for the presence of starch. Destarching the plant: The plant is placed in a dark place, e.g. a cupboard for 24 or 48 hours.

  5. Discovering Photosynthesis: Testing a Leaf for Starch

    Dive into the captivating world of plant biology with our hands-on practical experiment, designed to demonstrate the process of photosynthesis by testing a leaf for starch. By examining starch production in leaves, we can explore the incredible process through which plants convert sunlight into energy, producing the oxygen we breathe and the food we eat.…

  6. PDF Testing for Starch in Leaves

    Place the geranium leaf into the alcohol. e.Turn off the hotplate. Place the beaker containing the alcohol and geranium leaf into the beaker on the hot plate using tongs. f. When the leaf is white take it out of the test tube g.Soften the leaf by dipping it into the hot water for 2-3 seconds. h.Spread the leaf on a petri dish. Cover the leaf ...

  7. PDF Lab 12 Photosynthesis

    produced during photosynthesis, the presence of starch will be used in most experiments to verify ... to stain the starch stored in a leaf. Materials for Exercise 4: 1 clean 250 ml beaker; 1 clean 500 ml beaker Alcohol solution (80% ethanol) Variegated geranium leaf with a section wrapped in foil Petri dish

  8. Testing a leaf for starch for IGCSE Biology

    This is a step by step demonstration of how to test a leaf for starch. Each step is explained. I'm using a variegated geranium leaf which has cholophyll onl...

  9. Exploring Photosynthesis Variables: A Comprehensive Leaf Starch Test

    Discover the fascinating world of plant biology by conducting a comprehensive practical experiment that tests the effects of different variables on photosynthesis in leaves. This hands-on activity modifies light exposure and carbon dioxide availability, allowing students to observe the impact of these factors on starch production in leaves. By understanding how these variables influence ...

  10. School Science/Testing leaves for starch

    Method. Arrange the apparatus as shown in the figure. Place a beaker of hot water in the hot water bath. When the water has boiled add the leaf that had been in light. Wait 3 minutes for the leaf to boil (this is to get rid of the waterproof layer and break the open cells and make it soft). Take out the leaf using the forceps.

  11. Testing a Leaf for Starch

    The video above shows the steps in Testing a Leaf for the Presence of Starch. The Procedure outlined below is slightly different. Remove a green leaf from a plant that has been exposed to sunlight for a few hours. Half-fill a 250cm3 beaker with water. Heat the water until it boils.

  12. Using Pelargoniums (Geraniums) in the Lab

    Much more than just the 'starch test plant', geraniums can be used for a wide variety of topics from adaptation to pollen tube growth. Coming from the arid regions of South Africa, geraniums are well adapted to the rigours of life on a lab windowsill. Practicals. Photosynthesis: starch as a storage substance.

  13. A test of starch for a leaf(Geranium plant)

    geranium plant experiment for producing starch during photosynthesisby:ali fakih mostafa kazan mohomad ali kazan

  14. Leaf Starch Test: Principle, Procedure, Results, Uses

    Procedure of Leaf Starch Test. Pluck a green leaf of any outdoor plant. A medium size leaf, preferably, a leaf recently exposed to sunlight is better for this test. Boil about 250 mL water in a beaker and put the leaf in the beaker and let it boil for a few minutes (2 to 5 minutes) till its waxy coat got off and it gets soft.

  15. PDF ESSAY #1 2007

    ESSAY #1 2007. Title: The success of photosynthesis in geranium leaves using visible light wavelengths. obstructed by black paper, and red, blue, and green translucent filters. I. Abstract. Photosynthesis is a process in which plants use light, water, and carbon dioxide to. produce sugars, water and oxygen. Chlorophyll a and chlorophyll b, in ...

  16. Simple Geranium Photosynthesis Experiment for Kids

    Photosynthesis Activity. The green from plant leaves comes from a chemical called chlorophyll. This chemical is produced during photosynthesis when the plant uses the sun light to produce their own food. In this experiment we had part of the leaves covered leaving only part of the leaves exposed to the light.

  17. Photosynthesis: testing a variegated leaf for starch

    This is activity 11 in the 'Photosynthesis: A Survival Guide' scheme and follows up from activity 10, 'What are chloroplasts'. Students carry out a starch test on a variegated leaf to demonstrate that only the parts containing chloroplasts are able to synthesise starch. This resource is designed for 11-14 pupils but could be extended ...

  18. Practical: Investigating Photosynthesis

    Investigating the requirement for light in photosynthesis. Before testing for starch, complete the following procedure: Method Part 1. Destarch the plant by placing it in a dark cupboard for 24 hours. This ensures that any starch already present in the leaves will be used up and will not affect the results of the experiment; Following de-starching, partially cover a leaf of the plant with ...

  19. GCSE Testing a Leaf for Starch

    pptx, 1.09 MB. A lesson based around the practical for testing for starch in a geranium leaf. Includes a reliable method. Technical notes. This works really well if it is prepared correctly - the plants must be de-starched in the dark for at least 2 days and then illuminated under bright light for about a day before the lesson.

  20. Investigation of Photosynthetic Properties In Spinach and Geranium

    present in spinach leaves, the presence of multiple pigments in spinach leaves, and the apparent relation between light and the production of starch inGeranium leaves was performed. The data illustrates the dependence of starch production on the availability of light in Geranium. It was found that spinach photosynthetic pigment absorbed light ...

  21. starch in leaves

    Muttley. Apr 10, 2017. #17. The problem with this practical is the time it takes to destarch the plant. The teachers order it for the next day and don't realise you need to leave it in the dark for a couple of days (with a pot of soda lime to make sure). The crappy Edexcel method doesn't help either.

  22. PDF An Iodine-Based Starch Test to Assist in Selecting Leaves for HLB Testing

    HLB-positive leaves and nutrient-deficient leaves, after iodine staining. Healthy leaves may show some starch staining; however, it is generally confined to a few cell layers at the upper side of the leaf and does not show the same. intensity of staining as an HLB-positive leaf (compare Figures 3B and 4). HLB-positive leaves stain a ver.