Biosphere IV Flashcards
What are the major types of Mycorrhizae?
Ectomycorrhizae and endomycorrhizae, which consists of arbuscular, orchid, and ericoid mycorrhizae.
What type of ecosystems do ecto-mycorrhizae thrive in?
Higher latitudes, mostly forests, wood plant species
What type of ecosystems do arbuscular mycorrhizae thrive in?
Grasslands, mixed forests, crops, lower latitudes
What are the major morphological characteristics of arbuscular mycorrhizae?
They have arbuscules, which are small branched structures that grow in the plant cell and that exchange nutrients. They also have vesicles, which are storage units, and spores, which are the asexual reproduction units.
How do arbuscular mycorrhizae compare to other mycorrhizae types in terms of age, commonality, and diversity?
They are the oldest mycorrhizae type but are also less diverse than other types. They are the most common type of mycorrhizae.
What is the major advantage that arbuscular mycorrhizae provide to their associated plant?
They help increasing P uptake
What type of lifestyle do arbuscular mycorrhizae have?
They are obligate symbionts, not host specific
What are the major morphological characteristics of ectomycorrhizae?
They grow in between plant cells (not in cells like AMF) and have a larger hyphal network compared to AMF.
What types of fungi associate with ectomycorrhiza?
Some basidiomycota, some ascomycota
What type of lifestyle do ectomycorrhizae have?
They can exist in the soil by themselves and access organic N, and are not obligate symbionts. They can be saprotophic.
How does the distribution of EM vs AM vary according to latitude? Why?
With increasing latitude, there is more EM. This is likely because at higher latitudes there is an increasing percentage of nutrients bound in organic matter, which benefits organisms that can decompose. There is also more OM at higher latitudes.
Describe the relationship between nutrient cycling, plant species, and fungi for AM vs EM dominated ecosystems.
Grasses tend to have higher nutrients available, meaning that it decomposes more rapidly. Therefore, faster mineralization rates, during which we get the release of plant-available nitrogen. There is less need for the enzymes from an ectomycorrhizae to break down the organic matter.
In forest, the nutrients are tied up in the organic layer because decomposition of plant material is slow. Need the EM fungi to get decompose organic matter.
How does adding fertilizer affect the community of AMF fungi?
If you add fertilizer, the plants won’t need to rely on the fungi anymore, as there will already be enough phosphorus. So, in systems where P concentrations are high, we see the symbiosis decrease and tend to get less C delivered to the fungi.
How does tillage affect the AMF fungi community?
Tillage breaks down the hyphae, which will slow the growth of EMF.
How does no till and no fertilizer affect the AMF fungi community? Which component has a bigger effect?
It makes the community’s roots grow. The no till has a bigger positive impact than no fertilizer, but both work together. This benefits the crops as well: the aboveground biomass and nitrogen concentration also increases.
