Deck 37: Soil and Plant Nutrition

Question 1

Why does overwatering a plant kill it?

A)Water does not have all the necessary minerals a plant needs to grow.
B)Water neutralizes the pH of the soil.
C)The roots are deprived of oxygen.
D)Water supports the growth of root parasites.
E)Water lowers the water potential of the roots.

Answer 1

C

Question 2

If you wanted to increase the cation exchange and water retention capacity of loamy soil,what should you do?

A)adjust the soil pH to 7.9
B)add clay to the soil
C)practise no-till agriculture
D)add fertilizer containing potassium, calcium, and magnesium to the soil
E)increase the number of sand particles in the soil

Answer 2

B

Question 3

All of the following contributed to the dust bowl in the American southwest during the 1930s except

A)overgrazing by cattle.
B)clear-cutting of forest trees.
C)plowing of native grasses.
D)planting of field crops.
E)lack of soil moisture.

Answer 3

B

Question 4

Which of the following would be the most effective strategy to remove toxic heavy metals from a soil?

A)heavy irrigation to leach out the heavy metals
B)application of fertilizers to compete with heavy metal uptake
C)application of sulphur to lower the soil pH and precipitate the heavy metals
D)adding plant species that have the ability to take up and volatilize heavy metals
E)inoculating soil with mycorrhizae to avoid heavy metal uptake

Question 5

A young farmer purchases some land in a relatively arid area and is interested in earning a reasonable profit for many years.Which of the following strategies would best allow the farmer to achieve such a goal?

A)establishing an extensive irrigation system
B)using plenty of the best fertilizers
C)finding a way to sell all parts of crop plants
D)selecting crops adapted to arid areas
E)converting hillsides into fields

Question 6

For this pair of items,choose the option that best describes their relationship.
I)the average size of particles that constitute silt
II)the average size of particles that constitute clay

A)Item I is larger than item II.
B)Item I is smaller than item II.
C)Item I is exactly or very approximately equal to item II.
D)Item I bears no relationship to item II.

Question 7

A farming commitment that embraces a variety of methods that are conservation-minded,environmentally safe,and profitable is called

A)hydroponics.
B)nitrogen fixation.
C)responsible irrigation.
D)genetic engineering.
E)sustainable agriculture.

Question 8

A soil well suited for the growth of most plants would have all of the following properties except

A)abundant humus.
B)air spaces.
C)good drainage.
D)high cation exchange capacity.
E)a high pH.

Question 9

Which of the following would be in the lowest concentration in an actively growing shoot tip?

A)zinc
B)nitrogen
C)phosphorus
D)potassium
E)calcium

Question 10

There are several properties that are characteristic of a soil in which typical plants would grow well.Of the following,which would be the least conducive to plant growth?

A)abundant humus
B)numerous soil organisms
C)compacted soil
D)high porosity
E)high cation exchange capacity

Question 11

For this pair of items,choose the option that best describes their relationship.
I)the amount of nitrogen in a fertilizer marked "15-10-5"
II)the amount of nitrogen in a fertilizer marked "15-5-5"

A)Item I is greater than item II.
B)Item I is less than item II.
C)Item I is exactly or very approximately equal to item II.
D)Item I is unrelated to item II.

Question 12

Which of the following plant structures shares the most common features and functions with a fungal hyphae?

A)stomata
B)vascular cambium
C)lenticels
D)root hairs
E)prop roots

Question 13

Most of the water taken up by a plant is

A)used as a solvent.
B)used as a hydrogen source in photosynthesis.
C)lost during transpiration.
D)converted to CO₂.
E)used to keep cells turgid.

Question 14

For this pair of items,choose the option that best describes their relationship.
I)the amount of molybdenum in a gram of dried plant material
II)the amount of sulphur in a gram of dried plant material

A)Item I is greater than item II.
B)Item I is less than item II.
C)Item I is exactly or very approximately equal to item II.
D)There is not enough information to make a meaningful comparison.

Question 15

Which of the following soil minerals is most likely leached away during a hard rain?

A)Na⁺
B)K⁺
C)Ca⁺⁺
D)NO₃⁻
E)H⁺

Question 16

The NPK percentages on a package of fertilizer refer to the

A)total protein content of the three major ingredients of the fertilizer.
B)percentages of manure collected from different types of animals.
C)relative percentages of organic and inorganic nutrients in the fertilizer.
D)percentages of three important mineral nutrients.
E)proportions of three different nitrogen sources.

Question 17

What soil(s)is (are)the most fertile?

A)humus only
B)loam only
C)silt only
D)clay only
E)both humus and loam

Question 18

A soil can be amended to reduce minerals from leaching into the water table by adding

A)humus.
B)sand.
C)mycorrhizae.
D)nitrogen.
E)silt.

Question 19

Most of the dry weight of a plant is the result of uptake of

A)water and minerals through root hairs.
B)water and minerals through mycorrhizae.
C)CO₂ through stoma.
D)CO₂ and O₂ through stomata in leaves.
E)carbohydrates in the root hairs and concentration in the root cortex.

Question 20

A researcher analyzes the mineral content of a particular grass and is surprised to find substantial levels of uranium in both leaf and root tissues.The most likely explanation for this finding is that

A)uranium is an essential nutrient for this grass.
B)the plant has a mutation in its active transport proteins.
C)there is a higher than usual concentration of uranium in the soil.
D)uranium is substituting for some other essential nutrient.
E)uranium is being supplied by mycorrhizae.

Question 21

A farmer noted that many of his tomato fruits turned brown at the base as they ripened.The following spring when he replanted,seedlings only grew for a few weeks before the apical tips of many of the plants turned brown and the plants ultimately died.The most likely explanation for this observation is a soil deficiency in

A)nitrogen.
B)phosphorus.
C)potassium.
D)calcium.
E)magnesium.

Question 22

A growing plant exhibits chlorosis of the leaves,especially the older,more mature ones.The chlorosis is probably due to a deficiency of which of the following macronutrients?

A)carbon
B)oxygen
C)nitrogen
D)calcium
E)hydrogen

Question 23

In the 1640s,Jan Baptista van Helmont planted a small willow in a pot that contained 90.9 kg of soil.After five years,the plant weighed 76.8 kg,but only 0.06 kg of soil had disappeared from the pot.What did van Helmont conclude from this experiment?

A)80-90% of the tree's mass is the result of C₃ photosynthesis.
B)The increase in the mass of the tree was from the water that he added over the five years.
C)Most of the increase in the mass of the tree was due to the uptake of CO₂.
D)Soil simply provides physical support for the tree without providing any nutrients.
E)The 0.06 kg of soil was mainly nitrogen.

Question 24

When comparing a developing leaf with a fully mature leaf,the developing leaf will have

A)a lower water content.
B)higher nutrient levels.
C)a lower DNA content.
D)a higher photosynthetic rate.
E)a lower gas exchange rate.

Question 25

Most of the dry weight of a plant is derived from

A)NO₃ and CO₂.
B)K and CO₂.
C)PO₄ and K.
D)H₂O and K.
E)H₂O and CO₂.

Question 26

Which of the following are problems associated with intensive irrigation?
I) mineral runoff
II) over fertilization
III)aquifer depletion
IV)soil salinization

A)only I and II
B)only I, III, and IV
C)only III and IV
D)I, II, III, and IV

Question 27

Which of the following elements is incorrectly paired with its function in a plant?

A)nitrogen-component of nucleic acids, proteins, hormones, coenzymes
B)magnesium-component of chlorophyll; activates many enzymes
C)phosphorus-component of nucleic acids, phospholipids, ATP, several coenzymes
D)potassium-cofactor functional in protein synthesis, osmosis, operation of stomata
E)sulphur-component of DNA; activates some enzymes

Question 28

Which of the following essential nutrients plays an essential role in the opening and closing of the stomatal aperture?

A)Fe
B)Bo
C)Mg
D)H
E)K

Question 29

Which two elements make up more than 90% of the dry weight of plants?

A)carbon and nitrogen
B)oxygen and hydrogen
C)nitrogen and oxygen
D)oxygen and carbon
E)carbon and potassium

Question 30

Which of the following best describes the general role of micronutrients in plants?

A)They are cofactors in enzymatic reactions.
B)They are necessary for essential regulatory functions.
C)They prevent chlorosis.
D)They are components of nucleic acids.
E)They are necessary for the formation of cell walls.

Question 31

Which of the following elements,if increased in concentration,would increase the stability of cell walls?

A)zinc
B)chlorine
C)calcium
D)molybdenum
E)manganese

Question 32

Clay in soils represents a trade-off in nutrient availability,such that

A)anions are less likely to leach out of soil and are difficult for plants to extract.
B)cations are less likely to leach out of soil and are difficult for plants to extract.
C)nitrogen levels are exceptionally high, but much of the nitrogen leaches away.
D)oxygen levels are exceptionally high, but much of the nitrogen leaches away.

Question 33

The bulk of a plant's dry weight is derived from

A)soil minerals.
B)CO₂.
C)the hydrogen from H₂O.
D)the oxygen from H₂O.
E)the uptake of organic nutrients from the soil.

Question 34

In hydroponic culture,what is the purpose of bubbling air into the solute?

A)to keep dissolved nutrients evenly distributed
B)to provide oxygen to the root cells
C)to inhibit the growth of aerobic algae
D)to inhibit the growth of anaerobic bacteria
E)to provide CO₂ for photosynthesis

Question 35

Synthesis of which of the following compounds in a mature leaf would be least impacted by a temporary soil nitrogen deficiency?

A)chlorophyll
B)DNA
C)RNA
D)amino acids
E)cellulose

Question 36

Which of the following is of least concern to a researcher in a mineral nutrition experiment?

A)purity of the chemicals used to make the nutrient solutions
B)purity of the water used to make the nutrient solutions
C)chemical inertness of the container used to make and store the nutrient solutions
D)ability of a laboratory balance to weigh very small quantities of chemicals
E)medium in which the test seedlings were grown

Question 37

What is a major function of magnesium in plants?

A)to be a component of lignin-biosynthetic enzymes
B)to be a component of DNA and RNA
C)to be a component of chlorophyll
D)to be active in amino acid formation
E)to be required to regenerate phosphoenolpyruvate in C₄ and CAM plants

Question 38

Why does planting a cover crop help conserve soil?
I)controls weed populations
II)reduces soil loss due to wind and water erosion
III)increases soil nutrients when plowed under and allowed to decompose

A)only I
B)only I and II
C)only II and III
D)I, II, and III

Question 39

When performing a mineral nutrition experiment,researchers use water from a glass still.Why is it not a good idea to use regular distilled water from a stainless steel still?

A)With a steel still, lime deposits from hard water will build up too quickly.
B)Salts in the water corrode steel more quickly than glass.
C)Metal ions dissolving off the steel may serve as micronutrients.
D)A glass still allows the distillation process to be observed.
E)There is no difference; both kinds of stills produce distilled water.

Question 40

Reddish-purple colouring of leaves,especially along the margins of young leaves,is a typical symptom of deficiency of which element?

A)C
B)M⁺⁺
C)N
D)P
E)K⁺

Question 41

In what way do nitrogen compounds differ from other minerals needed by plants?

A)Only nitrogen can be lost from the soil.
B)Only nitrogen requires the action of bacteria to be made available to plants.
C)Only nitrogen is needed for protein synthesis.
D)Only nitrogen is held by cation exchange capacity in the soil.
E)Only nitrogen can be absorbed by root hairs.

Question 42

Which of the following experiments is the best way to determine if an element is essential for plant growth?

A)Measure the amount of the element stored in plant tissues.
B)Measure the amount of the element in the soil after plant growth.
C)Measure the weight of the plant and soil before and after plant growth.
D)Grow a plant using hydroponics with and without the element.

Question 43

If a plant is infected with nitrogen-fixing bacteria,what is the most probable effect on the plant?

A)It gets chlorosis.
B)It dies.
C)It is supplied with increased essential elements from the soil.
D)It will likely grow faster.
E)It becomes flaccid due to the loss of water and nutrients from the roots.

Question 44

You are weeding your garden when you accidentally expose some roots of your pea plants.You notice swellings (root nodules)on the roots and there is a reddish tinge to the ones you accidentally damaged.Most likely your pea plants

A)suffer from a mineral deficiency.
B)are infected with a parasite.
C)are benefiting from a mutualistic bacterium.
D)are developing offshoots from the root.
E)contain developing insect pupa.

Question 45

Most of the dry mass of a plant is the result of uptake of

A)water and minerals through root hairs.
B)water and minerals through mycorrhizae.
C)carbon dioxide through stoma.
D)carbon dioxide and oxygen through stomata in leaves.

Question 46

Nitrogen fixation is a process that

A)recycles nitrogen compounds from dead and decaying materials.
B)converts ammonia to ammonium.
C)releases nitrate from the rock substrate.
D)converts nitrogen gas into ammonia.
E)recycles nitrogen compounds from dead and decaying materials, and converts ammonia to ammonium.

Question 47

How would you determine if certain minerals are essential for plant growth?

A)Crush the plant leaves, stems, and roots and measure which minerals are present after growth.
B)Grow the plant hydroponically without the mineral in question.
C)Weigh how much minerals are in the soil when the plant germinates and again after plant growth.
D)When the plant has grown, analyze the mineral deficiency symptoms.

Question 48

How would you expect the root system of a plant grown by hydroponics to compare to the root system of a plant grown in soil? The root system of a plant grown by hydroponics would be

A)more developed.
B)less developed.
C)about the same.
D)absent.

Question 49

Which of the following is not true of micronutrients in plants?

A)They are elements required in relatively small amounts.
B)They are required for a plant to grow from a seed and complete its life cycle.
C)They generally help in catalytic functions in the plant.
D)They are the essential elements of small size and molecular weight.
E)Deficiencies vary widely by soil type.

Question 50

The enzyme complex nitrogenase catalyzes the reaction that reduces atmospheric nitrogen to

A)N₂.
B)NH₃.
C)NO₂.
D)NO⁺.
E)NO⁻.

Question 51

How do macronutrients differ from micronutrients?

A)They differ in whether they are essential for plant growth and survival.
B)They differ in their availability in soil.
C)They differ in how much nitrogen, phosphorus, and potassium are present.
D)They differ in the amount of the nutrient that plants require.

Question 52

Iron deficiency is often indicated by yellowing in newly formed leaves.This suggests that iron

A)is a relatively immobile nutrient in plants.
B)is tied up in formed chlorophyll molecules.
C)is concentrated in the xylem of older leaves.
D)is concentrated in the phloem of older leaves.
E)is found in leghemoglobin and reduces the amount available to new plant parts.

Question 53

Why is nitrogen fixation an essential process?

A)Nitrogen fixation can only be done by certain prokaryotes.
B)Fixed nitrogen is often the limiting factor in plant growth.
C)Nitrogen fixation is very expensive in terms of metabolic energy.
D)Nitrogen fixers are sometimes symbiotic with legumes.
E)Nitrogen-fixing capacity can be genetically engineered.

Question 54

Which of the following,if used as a fertilizer,would be most immediately available for plant uptake?

A)NH₃
B)N₂
C)CN₂H₂
D)NO₃
E)amino acids

Question 55

Which of the following is a true statement about nitrogen fixation in root nodules?

A)The plant contributes the nitrogenase enzyme.
B)The process is relatively inexpensive in terms of ATP costs.
C)Leghemoglobin helps maintain a low O₂ concentration within the nodule.
D)The process tends to deplete nitrogen compounds in the soil.
E)The bacteria of the nodule are autotrophic.

Question 56

A corn (Zea mays)mutant is developed that is deficient in magnesium uptake.The most likely phenotypic expression would be

A)chlorosis, especially in the older leaves.
B)a purple tinge to actively growing shoots.
C)severely stunted root growth and branching.
D)a reduction in leaf surface area.
E)a delay in flowering.

Question 57

In a root nodule,the gene coding for nitrogenase

A)is inactivated by leghemoglobin.
B)is absent in active bacteroids.
C)is found in the cells of the pericycle.
D)protects the nodule from nitrogen.
E)is part of the Rhizobium genome.

Question 58

The most efficient way to increase essential amino acids in crop plants for human consumption would be to

A)breed for higher yield of deficient amino acids.
B)increase the amount of fertilizer used on fields.
C)use 20-20-20 fertilizer instead of 20-5-5 fertilizer.
D)engineer nitrogen-fixing nodules into crop plants lacking them.
E)increase irrigation of nitrogen-fixing crops.

Question 59

Which of the following habitats would most likely have a high proportion of species of plants that are in symbiotic association with nitrogen-fixing bacteria?

A)anoxic soils such as fens and bogs
B)nutrient-limiting soils such as wet tropical rain forests
C)loamy soils such as temperate forests
D)agriculturally productive regions that have gone fallow
E)alpine coniferous forests

Question 60

If an African violet has chlorosis,which of the following elements might be a useful addition to the soil?

A)chlorine
B)molybdenum
C)copper
D)iodine
E)magnesium

Question 61

Which of the following is a primary difference between ectomycorrhizae and endomycorrhizae?

A)Endomycorrhizae have thicker, shorter hyphae than ectomycorrhizae.
B)Endomycorrhizae, but not ectomycorrhizae, form a dense sheath over the surface of the root.
C)Ectomycorrhizae do not penetrate root cells, whereas endomycorrhizae grow into invaginations of the root cell membranes.
D)Ectomycorrhizae are found in woody plant species; about 85% of plant families form ectomycorrhizae.
E)There are no significant differences between ectomycorrhizae and endomycorrhizae.

Question 62

The earliest vascular plants on land had underground stems (rhizomes)but no roots.Water and mineral nutrients were most likely obtained by

A)absorption by hairs and trichomes.
B)diffusion through stomata.
C)absorption by mycorrhizae.
D)osmosis through the root hairs.
E)diffusion across the cuticle of the rhizome.

Question 63

Rhizobia,actinomycetes,and cyanobacteria all share the common feature that they can

A)increase water uptake in plants.
B)increase nutrient availability in the soil for plants.
C)kill parasites in the soil.
D)exist in extreme environments.
E)fix atmospheric nitrogen.

Question 64

A woodlot was sprayed with a fungicide.What would be the most serious effect of such spraying?

A)a decrease in food for animals that eat mushrooms
B)an increase in rates of wood decay
C)a decrease in tree growth due to the death of mycorrhizae
D)an increase in the number of decomposing bacteria
E)a decrease in food for animals that eat mushrooms, and an increase in rates of wood decay

Question 65

Rhizobacteria aid plant growth in all the following ways,except

A)stimulate plant growth by producing specific chemicals.
B)protect roots from disease by producing antibiotics.
C)absorb toxic metals.
D)enable plants to tolerate specific stresses.
E)fix atmospheric nitrogen into ammonia.

Question 66

An example of a mutualistic association between a plant and a fungus would be

A)nitrogen fixation.
B)Rhizobium infection.
C)mycorrhizae.
D)parasitic infection.
E)assisted pollination.

Question 67

Dwarf mistletoe grows on many pine trees in the Rockies.Although the mistletoe is green,it is probably not sufficiently active in photosynthesis to produce all the sugar it needs.The mistletoe also produces haustoria.Thus,dwarf mistletoe growing on pine trees is best classified as

A)an epiphyte.
B)a nitrogen-fixing plant.
C)a carnivorous plant.
D)a symbiotic plant.
E)a parasite.

Question 68

Which of the following statements is not true about mycorrhizae?

A)Ectomycorrhizae form a dense sheet over the plant root, commonly observed in woody species.
B)Arbuscular mycorrhizae penetrate cell walls of the root cortex, forming structures called "little trees."
C)Roots can form a mycorrhizal symbiotic relationship with all species of fungi.
D)Fungi and bacteria can interact in ways that help plants respond to stressful conditions, such as contaminated soil.
E)Treating seeds with mycorrhizal fungi can improve crop yield.

Question 69

What major benefits do plants and mycorrhizal fungi receive from their symbiotic relationship?

A)Plants receive enzymes, and fungi receive nitrogen and phosphorus.
B)Plants receive increased root surface area, and fungi receive digestive enzymes.
C)Fungi receive photosynthetic products in exchange for living in plant root nodules.
D)Plants receive nitrogen and phosphorus, and fungi receive photosynthetic products.

Question 70

Carnivorous plants have evolved mechanisms that trap and digest small animals.The products of this digestion are used to supplement the plant's supply of

A)energy.
B)carbohydrates.
C)lipids and steroids.
D)minerals.
E)water.

Question 71

The following statements are true about carnivorous plants,with the exception of

A)all parasitic plants lack chlorophyll.
B)carnivorous plants do not require insects to survive.
C)many carnivorous plants live in acid bogs.
D)some plants are parasites of mycorrhizae.
E)carnivorous plants capture both insects and small mammals.

Question 72

The figure below shows the results of a study to determine the effect of soil air spaces on plant growth.

The best conclusion drawn from the data in the above figure is that the plant

A)grows best without air in the soil.
B)grows fastest in 5-10% air.
C)grows best at soil air levels above 15%.
D)does not respond differently to different levels of air in the soil.
E)would grow to 24 grams in 40% soil air.

Question 73

Which of the following is not a function of rhizobacteria?

A)produce hormones that stimulate plant growth
B)produce antibiotics that protect roots from disease
C)absorb toxic metals
D)carry out nitrogen fixation
E)supply growing roots with glucose

Question 74

Rhizobia and mycorrhizae share all of the following features except

A)they both benefit by receiving carbohydrate from the plant.
B)many are host-specific.
C)they both become parasitic in nutrient-rich environments.
D)they both enhance the growth of most plants.
E)they both are found in most ecosystems of the world.

Question 75

Hyphae form a covering over roots.These hyphae create a large surface area that helps to do which of the following?

A)aid in absorbing minerals and ions
B)maintain cell shape
C)increase cellular respiration
D)anchor a plant
E)protect the roots from ultraviolet light

Question 76

While hiking in a forest,you notice an unusual plant growing on the branches of a tree.What will help you to determine if this plant is epiphytic or parasitic?

A)If the plant is green, it is epiphytic; if not, then it is parasitic.
B)The root of an epiphytic plant will be in the soil, but a parasitic plant will grow from the trunk of a tree.
C)The roots of a parasitic plant will penetrate under the bark into the tree xylem, and the roots of epiphytic plant will not.
D)The epiphytic plant will have large water collecting leaves, and the parasitic plant will not.

Question 77

Plant roots can enhance the availability of mineral nutrients for uptake by

A)increased respiration.
B)increased photosynthesis.
C)release of chelating agents.
D)growing faster.
E)acidifying the soil.

Question 78

Which soil type or habitat would be least likely to have high populations of mycorrhizae?

A)acidic bogs and fens
B)loamy soils
C)sandy soils
D)tropical forests
E)desert soils

Question 79

What are epiphytes?

A)aerial vines common in tropical regions
B)haustoria used for anchoring to host plants and obtaining xylem sap
C)plants that live in poor soil and digest insects to obtain nitrogen
D)plants that grow on other plants but do not obtain nutrients from their hosts
E)plants that have a symbiotic relationship with fungi

Question 80

Upregulation of leghemoglobin biosynthesis in a leguminous species would most likely indicate

A)the plant is suffering from a mineral deficiency.
B)the successful inoculation of nitrogen-fixing bacteria.
C)the plant is suffering from water stress.
D)the plant has been infected with mycorrhizae.
E)an increase in the biosynthesis of amino acids.