1. What is mycorrhiza?
A) A type of plant hormone
B) A symbiotic association between fungi and plant roots
C) A parasitic relationship between fungi and plants
D) A type of root hair
Answer: B
Explanation: Mycorrhiza refers to the mutualistic association between plant roots and fungi, enhancing nutrient and water uptake in plants.
2. Which nutrient do mycorrhizae primarily help plants absorb?
A) Nitrogen
B) Phosphorus
C) Potassium
D) Calcium
Answer: B
Explanation: Mycorrhizae are particularly efficient in absorbing phosphorus from the soil, which is essential for plant growth.
3. What type of fungi forms mycorrhizal associations?
A) Yeast
B) Mushrooms
C) Glomeromycota
D) Ascomycota
Answer: C
Explanation: Glomeromycota fungi commonly form arbuscular mycorrhizal associations with plants, aiding in nutrient exchange.
4. What is the primary role of arbuscular mycorrhizae in plant nutrition?
A) Breaking down organic matter
B) Enhancing water and nutrient absorption
C) Fixing atmospheric nitrogen
D) Producing hormones
Answer: B
Explanation: Arbuscular mycorrhizae increase the surface area of plant roots for better absorption of water and nutrients, especially phosphorus.
5. Which plant group is most dependent on mycorrhizal associations?
A) Ferns
B) Gymnosperms
C) Angiosperms
D) All of the above
Answer: D
Explanation: Mycorrhizal associations are common in many plant groups, including ferns, gymnosperms, and angiosperms.
6. What is ectomycorrhiza?
A) Fungi that invade plant cells
B) Fungi that form a sheath around plant roots
C) Fungi that parasitize plant roots
D) Fungi that decompose dead plants
Answer: B
Explanation: Ectomycorrhizae form a sheath around plant roots and extend into the soil to enhance nutrient absorption.
7. Mycorrhizae help plants in saline soils by:
A) Providing salt tolerance
B) Increasing water uptake
C) Both A and B
D) None of the above
Answer: C
Explanation: Mycorrhizae improve plant salt tolerance and enhance water absorption in saline conditions.
8. How do mycorrhizae benefit fungi in the relationship?
A) Provide nutrients
B) Supply organic carbon from the plant
C) Offer water
D) Produce spores
Answer: B
Explanation: Fungi benefit by obtaining organic carbon produced through the plant’s photosynthesis.
9. What structure is formed by fungi inside plant roots in arbuscular mycorrhizae?
A) Hyphae
B) Arbuscules
C) Mycelium
D) Spores
Answer: B
Explanation: Arbuscules are tree-like structures formed inside root cells to facilitate nutrient exchange.
10. Which plants lack mycorrhizal associations?
A) Orchids
B) Brassicaceae
C) Pine trees
D) Legumes
Answer: B
Explanation: Brassicaceae plants generally lack mycorrhizal associations due to specific root traits.
11. Mycorrhizae improve plant drought tolerance by:
A) Reducing transpiration
B) Enhancing water absorption
C) Storing water in fungal hyphae
D) None of the above
Answer: B
Explanation: Mycorrhizae improve plant drought tolerance by increasing root surface area and aiding in water uptake.
12. Vesicles in mycorrhizal fungi are:
A) Storage structures for nutrients
B) Photosynthetic structures
C) Reproductive spores
D) None of the above
Answer: A
Explanation: Vesicles are storage structures in mycorrhizal fungi, holding nutrients for future use.
13. Endomycorrhizae differ from ectomycorrhizae by:
A) Forming arbuscules inside root cells
B) Forming external fungal sheaths
C) Decomposing organic material
D) Fixing nitrogen
Answer: A
Explanation: Endomycorrhizae form arbuscules within root cells, unlike ectomycorrhizae that remain external.
14. Mycorrhizae increase plant resistance to:
A) Soil pathogens
B) Herbivores
C) Air pollution
D) None of the above
Answer: A
Explanation: Mycorrhizae protect plants from soil pathogens by outcompeting harmful microbes and boosting plant immunity.
15. What role do mycorrhizae play in nutrient cycling?
A) Fixing nitrogen
B) Decomposing organic matter
C) Recycling phosphorus and other minerals
D) Storing carbon
Answer: C
Explanation: Mycorrhizae play a critical role in cycling phosphorus and other essential nutrients in the ecosystem.
16. Which of the following crops benefit most from mycorrhizae?
A) Wheat
B) Rice
C) Maize
D) All of the above
Answer: D
Explanation: Crops like wheat, rice, and maize show improved growth due to enhanced nutrient uptake facilitated by mycorrhizae.
17. Mycorrhizae aid in soil aggregation by:
A) Producing glomalin
B) Absorbing water
C) Breaking down organic matter
D) Fixing nitrogen
Answer: A
Explanation: Mycorrhizal fungi secrete glomalin, which binds soil particles and improves soil structure.
18. Mycorrhizae are essential for plant growth in:
A) Fertile soils
B) Nutrient-poor soils
C) Waterlogged soils
D) Acidic soils
Answer: B
Explanation: Mycorrhizae are crucial in nutrient-poor soils, as they enhance nutrient uptake efficiency.
19. What is a key environmental benefit of mycorrhizae?
A) Reducing soil erosion
B) Mitigating climate change
C) Supporting plant diversity
D) All of the above
Answer: D
Explanation: Mycorrhizae contribute to soil health, plant diversity, and ecological balance, indirectly influencing climate.
20. Orchid seeds rely on mycorrhizal fungi for:
A) Photosynthesis
B) Germination and nutrient supply
C) Pollination
D) Water absorption
Answer: B
Explanation: Orchid seeds lack endosperm and depend on mycorrhizal fungi for nutrients during germination.
21. Mycorrhizal colonization is inhibited by:
A) Excess phosphorus in soil
B) Low water availability
C) Low nitrogen levels
D) Neutral soil pH
Answer: A
Explanation: High soil phosphorus levels reduce the dependency of plants on mycorrhizal fungi.
22. The relationship between mycorrhizae and plants is:
A) Commensalism
B) Parasitism
C) Mutualism
D) Amensalism
Answer: C
Explanation: Mycorrhizae and plants engage in mutualism, where both benefit from the association.
23. How do mycorrhizae reduce heavy metal toxicity?
A) Breaking down metals
B) Binding metals in the soil
C) Absorbing metals and detoxifying plants
D) All of the above
Answer: C
Explanation: Mycorrhizae absorb and sequester heavy metals, protecting plants from toxicity.
24. Mycorrhizae aid in reforestation by:
A) Enhancing seed dispersal
B) Supporting sapling growth
C) Fixing carbon in the soil
D) Protecting from herbivores
Answer: B
Explanation: Mycorrhizae improve nutrient and water uptake in saplings, ensuring better growth in reforestation projects.
25. Mycorrhizae contribute to plant diversity by:
A) Enhancing pollination
B) Reducing competition for nutrients
C) Supporting diverse plant communities
D) All of the above
Answer: C
Explanation: Mycorrhizae support plant diversity by enabling various species to thrive under nutrient-limited conditions.
