22 Questions
What is the main function of arbuscular mycorrhizal (AM) fungi in relation to plant performance?
Exchange nutrients with plants, especially phosphorus
Why do orchid seeds depend on mycorrhizae as seedlings?
To avoid the costs of photosynthesis
What is a common characteristic of orchids and Indian Pipes in relation to mycorrhizae?
They remain parasites even as mature plants
In what type of soils are mycorrhizae most useful?
Nutrient-poor soils
What negative effect can occur with the wrong combination of fungi and plants?
Negative effects
What is a characteristic of carnivorous plants in relation to mycorrhizae?
They are generally found in nutrient-poor sites
What is the primary source of nutrients for plants?
Mineral nutrients in soil water
Why is atmospheric nitrogen (N2) useless to most plants?
Plants cannot absorb nitrogen from the air
Which of the following nutrients are NOT generally absorbed by plant roots?
Organic compounds
What specialized mechanisms do plants use to absorb mineral nutrients from the soil?
Ion channels and energy-dependent processes
Why is the C:N ratio important in determining soil fertility?
It influences the decomposer activity and nutrient availability
What happens when decomposers retain nitrogen from the soil?
They immobilize nitrogen making it unavailable for plants
What is the optimal C:N ratio for decomposers?
25:1
Why does the growth of decomposers tend to be limited by N when the C:N ratio is over 25?
N becomes relatively overabundant
Which type of litter decays faster based on the text?
Litter with high N content
What are peatlands characterized by?
Low pH
What might result in the release of stored C from peatlands?
Climate change causing drying and fire
Which type of mycorrhizae penetrates the root according to the text?
Arbuscular mycorrhizae (AM)
What is a major input of N into ecosystems and soils according to the text?
Biological N fixation
Why is the process of biological N fixation poisoned by O2?
'Oxygen poisoned' N-fixing cells
'Excess water, low water movement, and reduced microbial activity' are characteristics of what ecosystem according to the text?
'Peatlands'
'Preserved by the lack of decomposition' is associated with which Iron-age body found in a bog according to the text?
'Tollund Man'
Explore key points about mineral nutrients including their source, uptake, and importance in plant growth. Learn about internal nutrient recycling processes within plants. Refer to Chapter 4 and 5 for more insights.
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