How does rose black spot affect the growth of plants?

How does rose black spot affect the growth of plants?

• A. Growth is increased due to more photosynthesis.
• B. Growth is reduced as there is less photosynthesis occurring.
• C. Plants become more resistant to pests.
• D. Flowering is unaffected.

Answer: (B)

The main idea is that diseases that damage leaves limit plant growth by cutting down photosynthesis. Rose black spot creates spots and causes leaves to yellow and drop, so there are fewer healthy leaves to capture light. With less light energy converted into sugars, the plant has less energy available for growth and for making new tissue, so overall growth is reduced. It can also lessen flowering because resources are diverted to defense and maintaining existing tissue rather than producing blooms. The other ideas aren’t correct because the disease does not increase photosynthesis, it does the opposite; it doesn’t make plants more pest-resistant, and flowering is typically affected, not completely unaffected.

The main idea is that diseases that damage leaves limit plant growth by cutting down photosynthesis. Rose black spot creates spots and causes leaves to yellow and drop, so there are fewer healthy leaves to capture light. With less light energy converted into sugars, the plant has less energy available for growth and for making new tissue, so overall growth is reduced. It can also lessen flowering because resources are diverted to defense and maintaining existing tissue rather than producing blooms. The other ideas aren’t correct because the disease does not increase photosynthesis, it does the opposite; it doesn’t make plants more pest-resistant, and flowering is typically affected, not completely unaffected.