This document discusses variegated leaves. It defines a leaf and its parts. Photosynthesis uses chlorophyll to convert carbon dioxide and water into glucose and oxygen. Variegation is different colored zones on leaves caused by cell mutation, genetics, or viruses. Types of variegation include chimeric (random cells), genetic (passed to offspring), and pathological (virus infections). Variegated plants can sometimes revert to being green.
3. What is a leaf?
◦ It is a flattened structure of a higher plant,
typically green and blade-like, that is
attached to a stem directly or via a
stalk/petiole.
◦ Leaves are the main organs of
photosynthesis and transpiration.
4. Parts of a Leaf
• Tip
• Midrib
• Margin
• Vein
• Lamina
• Petiole (or stalk; some leaves does not
have a petiole)
5. Parts of a Leaf
• Tip
• Margin
• Midrib
• Petiole (or stalk; some leaves does not
have a petiole)
• Vein
• Lamina
A
B
E
C
F
D
6. Chlorophyll and Starch in Leaves
◦ Chlorophyll is the green pigment in leaves.
◦ Photosynthesis is the process by which light energy is harvested by chlorophyll and used to
convert inorganic raw materials - carbon dioxide and water into the products glucose and
oxygen. Most photosynthesis takes places in the green parts of plants, in particular the leaves.
◦ The glucose molecule is a monosaccharide that through the process of dehydration synthesis
can form a larger molecule called a polysaccharide. This polysaccharide, starch, is stored inside
the chloroplast until it can be transported.
10. Causes of Variegation
◦ Lack of green pigment chlorophyll caused by cell mutation.
◦ Genetically-modified plants that are intended to have variegation.
◦ Natural feature of a certain plant species.
◦ Virus infections may cause patterning to appear on the leaf surface.
12. Chimeric
◦ Variegation occurs randomly.
◦ Cells of more than one genotype (genetic makeup) are found growing adjacent in the tissues of
that plant.
◦ A leaf can have both green chloroplasts and white chloroplasts. However, green chloroplasts
are more dominant in appearance compared to white chloroplasts.
◦ Caused by mutations in plant cells.
13. Genetic
◦ Variegation is a natural characteristic of a certain plant species (example: Snake plant).
◦ Color patterns will be passed after reproduction to their offspring.
14. Pathological
◦ Virus infections may cause patterning to appear on the leaf surface.
◦ Patterning is often a characteristic of an infection.
◦ Example: mosaic virus, which produce a mosaic-type effect on the leaf surface or the citrus
variegation virus (CVV).
16. Additional facts:
◦ Variegated plants can revert or turn green for several reasons. It can be a reaction to extremes
of hot and cold or a reaction to low-light levels. Some say it could also be caused as a survival
technique, as the plant is stronger when it has more chlorophyll (Lambert, 2018).
◦ It has been suggested that some patterns of leaf variegation may be part of a defensive
"masquerade strategy” (Lev-Yadun, 2014).
◦ Variegated plants are taken care of by some gardeners, as the usually lighter-colored variegation
can 'lift' what would otherwise be blocks of solid green foliage.
18. Identify the parts of leaf.
Choose from the items below.
• Lamina
• Tip
• Vein
• Margin
• Petiole
• Midrib
1
2
5
3
6
4
19. Answer the following questions on a piece of paper.
7. What is the term used to describe the appearance of differently colored zones mostly in the
leaves and sometimes the stems of plants?
8-9. Give two possible causes of variegation.
10. What is the type of variegation that occurs randomly?
11. Name of the virus that produces a mosaic-type effect on leaf surfaces.
12. State an example of a plant that has a variegation under genetic type.
21. Identify the parts of leaf.
Choose from the items below.
• Lamina
• Tip
• Vein
• Margin
• Petiole
• Midrib
1
2
5
3
6
4
22. Answers to questions 7 to 12:
7. Variegation or Variegated
8-9. Any of these:
Lack of green pigment chlorophyll caused by cell mutation.
Genetically-modified plants that are intended to have variegation.
Natural feature of a certain plant species.
Virus infections may cause patterning to appear on the leaf surface.
10. Chimeric
11. Mosaic virus
12. Snake plant
