Red, violet and brown leaves
Why not every leaf is green.
Not all leaves are green
Some plants have red, violet or brown leaves. They are leaves too.
Why do you think a red leaf does not look green?
What this lesson covers
The idea
Some leaves look red, violet or brown because they contain more of these coloured pigments than chlorophyll, hiding the green; some of these pigments also help in photosynthesis.
Not all leaves are green
Some plants have red, violet or brown leaves. They are leaves too.
Why do you think a red leaf does not look green?
- It has more of a red pigment than green chlorophyll
- It has no pigment at all
- It is not a real leaf
Compare the pigments
Tap each leaf. The bars are a picture of more and less pigment.
Colour hides the green
A green leaf has plenty of chlorophyll. In a red, violet or brown leaf the other coloured pigment is more than chlorophyll, so the green cannot be seen. A teacher can use the iodine test on such leaves to check for starch. Starch shows that photosynthesis has taken place.
Some leaves look red, violet or brown because they contain more of these coloured pigments than chlorophyll, hiding the green; some of these pigments also help in photosynthesis.
Notes
Some leaves look red, violet or brown because they contain more of these coloured pigments than chlorophyll, hiding the green; some of these pigments also help in photosynthesis.
Check yourself
Why does a red leaf not look green?
Some pigments in red, violet or brown leaves also help in …
How can a teacher check if a red leaf has made starch?
A leaf looks violet. Which statement is right?
- It is not a leaf. It is a leaf. Its colour comes from the pigments it has.
- It has no chlorophyll at all. It still has chlorophyll. But it has more of the red pigment, which hides the green.
- It has more red pigment than chlorophyll — correct. Yes! The red pigment hides the green.
- photosynthesis — correct. Yes! They also help in photosynthesis.
- making the leaf broad and flat. The shape of a leaf is its design. Some of these pigments help in photosynthesis.
- taking up water from the soil. Roots take up water from the soil. Some of these pigments help in photosynthesis.
- Look at its red colour. The red colour does not tell us about starch. The iodine test does.
- Do the iodine test — correct. Yes! Starch turns the leaf blue-black.
- Weigh the leaf. Weight does not show starch. The iodine test does.
- Violet leaves can never do photosynthesis. Some of these pigments also help in photosynthesis.
- Its chlorophyll has turned violet. Chlorophyll is green. The violet colour comes from another pigment.
- It has more violet pigment than chlorophyll — correct. Yes! The violet pigment hides the green.