Campbell’s Biology, 9e (Reece et al.)
Chapter 37 Soil and Plant Nutrition
In this chapter, students are introduced to the basic nutritional requirements of plants and learn how
plants (and autotrophic organisms in general) obtain the majority of their body mass from CO2 and
water. The essential elements and their functions in plants are outlined in detail and can serve as a basis
for comparison in later chapters exploring animal nutritional requirements.
Multiple-Choice Questions
1) 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.
2) For this pair of items, choose the option that best describes their relationship.
(A) The average size of particles that constitute silt
(B) The average size of particles that constitute clay
A) Item (A) is larger than item (B).
B) Item (A) is smaller than item (B).
C) Item (A) is exactly or very approximately equal to item (B).
D) Item (A) bears no relationship to item (B).
3) For this pair of items, choose the option that best describes their relationship.
(A) The amount of nitrogen in a fertilizer marked “15-10-5”
(B) The amount of nitrogen in a fertilizer marked “15-5-5”
A) Item (A) is greater than item (B).
B) Item (A) is less than item (B).
C) Item (A) is exactly or very approximately equal to item (B).
D) Item (A) is unrelated to item (B).
4) For this pair of items, choose the option that best describes their relationship.
(A) The amount of molybdenum in a gram of dried plant material
(B) The amount of sulfur in a gram of dried plant material
A) Item (A) is greater than item (B).
B) Item (A) is less than item (B).
C) Item (A) is exactly or very approximately equal to item (B).
D) There is not enough information to make a meaningful comparison.
5) 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
6) 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.
7) 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
8) 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) practice no-till agriculture
D) add fertilizer containing potassium, calcium, and magnesium to the soil
E) increase the number of sand particles in the soil
9) 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.
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
11) 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.
12) 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
13) 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.
14) 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.
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+
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.
17) 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
18) 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.
19) 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 sulfur 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
20) 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.
21) 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.
22) 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
23) 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.
24) 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
25) 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
26) 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
27) 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.
28) 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.
29) 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
30) 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) sulfur component of DNA; activates some enzymes
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
32) 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.
33) 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.
34) 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
35) 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
36) Reddish-purple coloring 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+
37) 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.
38) 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.
39) 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.
40) 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
41) 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.
42) 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.
43) 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.
44) 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.
45) 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