The Real Reason Leaves Change Color in the Fall

In autumn, leaves change color as chlorophyll breaks down, revealing yellow and orange pigments. Deciduous trees recycle nutrients from leaves before shedding them to conserve resources. Chlorophyll breakdown is managed to prevent damage from reactive oxygen. Some trees produce red pigments for protection. This process helps trees recover nutrients for new growth in spring.

Why do leaves appear yellow and orange in autumn?

• Due to the loss of green chlorophyll revealing existing pigments.

• Because the tree injects yellow and orange dyes.

• Due to a chemical reaction with the soil.

• Because they gain new pigments in autumn.

What is the primary reason deciduous trees shed their leaves annually?

• To avoid the high cost of winterizing them.

• To make room for new leaves immediately.

• To attract more sunlight.

• To prevent the tree from growing too tall.

How do trees manage the reactive oxygen molecules during leaf disassembly?

• By increasing photosynthesis.

• By breaking down chlorophyll into less harmful molecules.

• By absorbing more sunlight.

• By stopping all cellular activity.

What role do red and purple pigments play in some trees during autumn?

• They attract pollinators.

• They protect chlorophyll from sunlight.

• They store extra nutrients.

• They help in photosynthesis.

What percentage of nitrogen and phosphorus can trees recover from their old leaves?

• 50%

• 25%

• 10%

• 75%