Soil Food Web 1
What is the rhizosphere?
The area immediately around a root.
Why are there higher numbers of microbes in the rhizoshpere than in the rest of the soil?
Root exudates feed the microbes there.
Why is it unlikely that plants grown hydroponically will reach levels 3 and 4 of the plant health pyramid?
To reach these levels requires soil biology.
During rhizophagy, bacteria are taken into a plant's root and ejected out of the root. From what part of the root are they ejected?
Tip of root hair
Why did John Kempf say that plants are not vegetarian?
They consume bacteria.
Some fungi catch and eat nematodes. How do they do it?
They form loops of hyphae and when a nematode puts its head through a loop, it contracts and catches the nematode.
What are the 3 classes of protozoa?
Amoeba, flagelate, cilliate
Explain William Albrecht's statement that insects are nature's garbage collectors and diseases are her clean-up crew.
Insects and diseases only eat plants that are not healthy
It is important to feed the soil microbes every day. How can you do that?
Have plants growing in the soil, which will feed the microbes with their root exudates. A mulch can also do it.
Sometimes the surface of seeds is sterilized to ensure there are no pathogenic microbes on the seeds. Why is this not a good idea?
There are beneficial microbes on the seed that will promote the growth of the plant and make it healthier. These beneficial microbes will be killed by the sterilization.
How do both the plant and the fungus benefit from a mycorrhizal relationship?
The fungus gains food from the plant in the form of sugars and other organic compounds. The plant gains water and mineral nutrients that the fungus extracts from the soil.
What are the 2 most common types of mycorrhizal fungi and what is the main difference in how they interact with the plant root?
Endomycorrhizal fungi extend into the cells of plant roots. Ectomycorrhizal fungi surround the root and grow into the plant root but remain between the cells, not inside of the cells.
Why are some trace minerals needed for complete protein synthesis?
Trace minerals are needed as co-factors in enzymes that synthesize proteins.
How does rhizophagy play a role in the plant health pyramid?
It takes less energy for a plant to obtain nurtients through rhizophagy than to take in soluble minerals from the soil so it has more energy to make lipids and secondary metabolites.
Why does John Kempf recommend not to use composted animal manure?
The high levels of nitrogen and potassium in these manures can promote diseases and insects problems.
What are 3 benefits of mycorrhizal fungi?
They provide mineral nutrients to the plant, protect the plant from pathogens, improve soil aggregation, increase accumulation of organic matter in the soil, decompose organic matter, and are food for some other organisms in the soil food web.
Different types of nematodes eat different things. What are 3 things a nematode might eat?
Bacteria, fungi, other nematodes, plants.
How does complete protein synthesis protect plants from insects with simple digestive systems?
These insects do not have the enzymes to digest complete proteins, so they are not able to digest the plants.
In what way do bacteria and fungi each influence soil pH?
Bacteria increase pH, fungi decrease pH.
How do the populations of bacteria and fungi change as a plot of land goes from disturbed soil and weeds to grasses to perennials to shrubs to forest?
The amount of bacteria stays about the same but at each step there is more fungi, resulting in a higher fungal to bacteria ratio.
Describe the steps and the types of organisms involved starting with plant roots exuding sugars and ending with the plant roots absorbing needed minerals.
Bacteria and fungi eat the sugars and other plant exudates. The bacteria and fungi digest organic matter and use their enzymes and organic acids to extract minerals from soil particles. Protozoans, microarthropods and nematodes eat the bacteria and fungi and excrete some of minerals that the bacteria & fungi got from the organic matter and soil particles. These minerals are excreted in forms that the plant can easily take up and use.
Relate the Science of Consciousness principle that the whole is more than the sum of the parts to the soil food web.
Each member of the soil food web is just doing what it needs to do to gain nourishment and survive, but the soil food web, as a whole, creates healthy soil, healthy plants, healthy people and other animals that eat the plants, prevents erosion, sequesters carbon, etc.
Name the 4 levels of the plant health pyramid.
Complete photosynthesis, complete protein synthesis, increased lipid synthesis, increased secondary metabolite synthesis.
What are mineralization and immobilization?
Mineralization is making plant nutrients into soluble mineral forms, such as nitrate and ammonium. This happens when a predator eats an organism and it's waste contains the unneeded nutrients. Immobilization is when an organism consumes a soluble nutrient and incorporates it into its body.
What types of plants do ectomycorrhizal fungi associate with?
Conifers and some hardwood trees