CHAPTER 35—PLANT NUTRITION
MULTIPLE CHOICE
1. Which of the following is typically FALSE for tropical rainforests?
a.
Tropical rainforests are biologically diverse ecosystems.
b.
Tropical rainforest soils have high acidity.
c.
Minerals such as calcium and phosphorus are subject to leaching from the upper tropical
rainforest soil level.
d.
Tropical rainforest soils are extremely rich in nutrients.
e.
Organic remains are decomposed rapidly in tropical rainforests.
2. When tropical forests are cut for agriculture, they often do not produce highly productive crop growth.
What is probably limiting the growth of a crop in the tropical forest?
a.
Sunlight.
b.
Rainfall.
c.
Carbon dioxide
d.
Soil nutrients.
e.
Bacteria.
3. Plant tissues are more than 90 percent ____ by weight.
a.
carbohydrates
b.
water
c.
carbon
d.
nitrogen
e.
cellulose
4. Hydroponic culture is the process of
a.
growing plants in pure water mixed with carefully measured amounts of specific minerals.
b.
irrigation of dry areas to improve mineral absorption by plants.
c.
growing plants in ponds and lakes to improve their access to water, allowing the plants to
place more resources into the shoot system.
d.
irrigation of dry areas to prevent crop plants from wilting.
e.
growing plants with specific hydrocarbons added to the soil to test the effect on plant
growth.
5. Which of the following macronutrients is rarely deficient?
a.
Carbon
b.
Hydrogen
c.
Oxygen
d.
Zinc
e.
Carbon Dioxide
6. Which of the following elements is considered an essential macronutrient for plants?
a.
gold
b.
manganese
c.
calcium
d.
nitrogen
e.
copper
7. Which of the following elements is considered an essential macronutrient for plants?
a.
zinc
b.
uranium
c.
iron
d.
nickel
e.
carbon
8. Which of the following elements is considered an essential macronutrient for plants?
a.
oxygen
b.
boron
c.
lithium
d.
silicon
e.
molybdenum
9. Which of the following elements is considered an essential micronutrient for plants?
a.
gold
b.
carbon
c.
uranium
d.
nitrogen
e.
copper
10. Which of the following elements is considered an essential micronutrient for plants?
a.
phosphorus
b.
silver
c.
molybdenum
d.
carbon
e.
lead
11. Which of the following elements is considered an essential micronutrient for plants?
a.
zinc
b.
potassium
c.
hydrogen
d.
arsenic
e.
platinum
12. Which of the following elements is considered an essential micronutrient for plants?
a.
calcium
b.
lithium
c.
sulfur
d.
nickel
e.
oxygen
13. Experiments have shown that even if it is supplied by no other means, plants near the ocean can get
enough of the essential micronutrient ____ from the air, and plants can also get this essential
micronutrient from sweat from a persons hands.
a.
sulfur
b.
manganese
c.
chlorine
d.
magnesium
e.
sodium
14. Which of the following statements about essential elements is FALSE?
a.
An element with only one role in plant metabolism may still be essential.
b.
An essential element is necessary for normal growth and reproduction.
c.
Plant seeds in some cases contain enough of an essential element to sustain the adult plant.
d.
An essential element may occasionally be functionally replaced by another element.
e.
Some essential elements are required in only trace amounts.
15. Which of the following elements is not considered an essential micronutrient for plants in general, but
is required by horsetails and perhaps some grasses such as wheat?
a.
gold
b.
boron
c.
silicon
d.
zinc
e.
magnesium
16. You might infer from packages of commercial fertilizer that which of the following nutrients are most
limiting to plant growth?
a.
Carbon, nitrogen and phosphorous.
b.
Nitrogen, phosphorous and potassium.
c.
Hydrogen, phosphorus and magnesium.
d.
Iron, Magnesium and nitrogen.
e.
Phosphorus, potassium, and calcium.
17. A common consequence of nutrient deficiencies in plants is chlorosis, which is
a.
wilting due to a lack of chlorine in leaves.
b.
death of the growing tips.
c.
premature loss of leaves.
d.
bursting of cells from excess water uptake due to an inability to clear chlorine from them.
e.
yellowing of plant tissues due to a lack of chlorophyll.
18. For which of the following nutrients does a deficiency not result in leaf chlorosis?
a.
Nitrogen.
b.
Magnesium.
c.
Iron.
d.
Zinc.
e.
Boron.
19. Soil particles that are decomposing organic matter are called
a.
sand.
b.
humus.
c.
silt.
d.
clay.
e.
mineral.
20. Soil mineral particles that range from 2.0−0.02 mm in diameter are called
a.
sand.
b.
humus.
c.
clay.
d.
silt.
e.
macroparticles.
21. Soil mineral particles that range from 0.02−0.002 mm in diameter are called
a.
sand.
b.
humus.
c.
clay.
d.
silt.
e.
macro/microparticles.
22. Soil mineral particles that are less than 0.002 mm in diameter are called
a.
sand.
b.
humus.
c.
clay.
d.
silt.
e.
microparticles.
23. A soil that is mostly ____ will tend to dry quickly compared to other soil types.
a.
sand
b.
humus
c.
clay
d.
silt
e.
organic matter
24. The soils in which most plants do best are
a.
mixtures of mainly sand and silt.
b.
sandy soils.
c.
soils made mostly of humus.
d.
clay soils.
e.
loams.
25. A soil with roughly equal amounts of humus, silt, clay, and sand is called a
a.
topsoil.
b.
loam.
c.
subsoil.
d.
compost.
e.
oversoil.
26. Research is Colorado’s San Juan Mountains has illustrated that in comparison to stands of lodgepole
pine and Englemann spruce, stands of trembling aspen have all of the following EXCEPT
a.
higher soil temperatures.
b.
more soil nitrate.
c.
different arrays of soil-dwelling organisms.
d.
light reaching the soil surface.
e.
more soil phosphorus.
27. Which soil region extends to the underlying bedrock, and consists of mineral particles and rock
fragments but generally no organic material?
a.
A horizon
b.
B horizon
c.
C horizon
d.
D horizon
e.
O horizon
28. Which soil region is the most fertile soil layer where the roots of most herbaceous plants are located?
a.
A horizon
b.
B horizon
c.
C horizon
d.
D horizon
e.
O horizon
29. Which soil region is the top layer of surface litter, such as twigs and leaves?
a.
A horizon
b.
B horizon
c.
C horizon
d.
D horizon
e.
O horizon
30. Which soil region tends to accumulate mineral ions but relatively little organic matter, and is generally
penetrated by mature tree roots?
a.
A horizon
b.
B horizon
c.
C horizon
d.
D horizon
e.
O horizon
31. Which of the following is most important for retaining water in soil for use by plants?
a.
sand
b.
humus
c.
clay
d.
silt
e.
rock
32. The surfaces of clay particles in soil
a.
often bear positively charged ions.
b.
release water to plants easily.
c.
often bear negatively charged ions.
d.
are generally hydrophobic.
e.
acidify the soil.
33. Most plants would grow best in which of the following situations?
a.
a soil with very small air spaces
b.
a soil with relatively large air spaces
c.
a soil with air spaces filled almost entirely with water
d.
a soil with various sizes of air spaces
e.
a soil with no air spaces
34. Roots obtain cations through cation exchange, where soil particles absorb ____ provided directly or
indirectly by the root, and thus release cations.
a.
Cl−
b.
K+
c.
H+
d.
water
e.
CO2
35. Areas that receive heavy rainfall tend to have ____ soils, and arid regions tend to have ____ soils.
a.
acidic; alkaline
b.
pH-neutral; acidic
c.
alkaline; acid
d.
acidic; pH-neutral
e.
pH-neutral; alkaline
36. Phytoremediation is
a.
rotating crops so that soil minerals are replenished.
b.
replacing eroded topsoil so that plants can grow in the soil again.
c.
plowing under all or parts of crops to improve the soil.
d.
the use of plants to remove pollutants from the environment.
e.
replacing unwanted plants with plants useful to humans.
37. Work by Scott Bizily, Richard Meagher, and colleagues in the 1990s produced Arabidopsis thaliana
plants that are able to take up ____ from the soil and convert it into a much less dangerous substance.
a.
arsenic
b.
methylmercury
c.
chelated iron
d.
lead
e.
uranium hexafluoride
38. Plants cannot enable and improve access to particular nutrients by
a.
releasing amino acids into the soil.
b.
releasing carbohydrates into the soil.
c.
releasing enzymes into the soil.
d.
releasing organic substances into the soil.
e.
releasing carbon dioxide into the soil.
39. Mycorrhizae are
a.
intertwined roots of different species of plants.
b.
connecting points between branching roots.
c.
symbiotic associations between a fungus and plant roots.
d.
specialized root hairs.
e.
localized swellings in plant roots filled with nitrogen-fixing bacteria.
40. Mycorrhizae, present for most plant species, generally help roots with the uptake of all EXCEPT
a.
water.
b.
nitrogen.
c.
phosphate.
d.
carbon.
e.
sugars.
41. The most common limit to plant growth is a lack of
a.
phosphorous.
b.
carbon.
c.
hydrogen.
d.
oxygen.
e.
nitrogen.
42. Plants can generally absorb and make use of nitrogen in the form of
a.
NO3− only.
b.
both NO3− and NH4+.
c.
NH4+ only.
d.
N2 only.
e.
both N2 and NH4+.
43. The process of adding hydrogen to N2, creating NH3 and eventually NH4+, and which requires a
substantial input of ATP, is called
a.
nitrification.
b.
ammonification.
c.
nitrogen cycling.
d.
nitrogen fixation.
e.
nitrogen assimilation.
44. The enzyme nitrogenase is most directly involved in the process called
a.
nitrification.
b.
ammonification.
c.
nitrogen cycling.
d.
nitrogen fixation.
e.
nitrogen assimilation.
45. The process of producing NH4+ from decaying organic material is called
a.
nitrification.
b.
ammonification.
c.
nitrogen cycling.
d.
nitrogen fixation.
e.
nitrogen assimilation.
46. The process in which NH4+ is oxidized to NO3− is called
a.
nitrification.
b.
ammonification.
c.
nitrogen cycling.
d.
nitrogen fixation.
e.
nitrogen assimilation.
47. Which of the following would you expect to happen if nitrifying bacteria were not present in a soil?
a.
Plants would take up nitrogen for their use mainly as NH4+
b.
Plants would not survive because they could not get useful nitrogen
c.
Plants would take up nitrogen for their use mainly as N2
d.
Plants would take up nitrogen for their use mainly as NH3
e.
Plants would take up nitrogen for their use mainly as NO3−
48. Which of the following is mostly performed by bacteria living within the roots of plants in the legume
family?
a.
nitrification
b.
ammonification
c.
nitrogen cycling
d.
nitrogen fixation
e.
nitrogen assimilation
49. Inside root cells, ____ is converted to ____, which is then rapidly used to synthesize organic
molecules.
a.
NH4+; NO3−
b.
N2; NO3−
c.
NO3−; NH4+
d.
NH3; NH4+
e.
NO3−; N2
50. Plants generally take up nitrogen for their use mainly as
a.
NH4+.
b.
CN.
c.
N2.
d.
NH3.
e.
NO3−.
51. Species of Rhizobium and Bradyrhizobium bacteria are most directly associated with
a.
nitrification.
b.
ammonification.
c.
nitrogen cycling.
d.
nitrogen fixation.
e.
nitrogen assimilation.
52. Root nodules are
a.
intertwined roots of different species of plants.
b.
connecting points between branching roots.
c.
symbiotic associations between a fungus and plant roots.
d.
specialized root hairs.
e.
localized swellings in plant roots filled with nitrogen-fixing bacteria.
53. Studies of a soybean plant (Glycine max) and the bacterium Bradyrhizobium japonicum have shown
that the tip of a root hair curls toward the bacterium in response to
a.
a flavonoid released by soybean roots.
b.
nod gene products produced by soybean roots.
c.
nod gene products produced by the bacterium.
d.
nitrogen fixation by the bacterium.
e.
a flavonoid produced by the bacterium.
54. Studies of a soybean plant (Glycine max) and the bacterium Bradyrhizobium japonicum have shown
that after the bacterium enters the root, cells of the root cortex begin to divide in response to
a.
a flavonoid released by soybean roots.
b.
nod gene products produced by soybean roots.
c.
nod gene products produced by the bacterium.
d.
nitrogen fixation by the bacterium.
e.
a flavonoid produced by the bacterium.
55. Bacteroids are
a.
specialized nitrifying bacteria.
b.
small buds from ammonifying bacteria.
c.
specialized bacteria that help some plant roots absorb phosphorus.
d.
enlarged and immobilized nitrogen-fixing bacteria.
e.
interactions between plant root hairs and bacteria.
56. Leghemoglobin, which contains an iron-containing heme group, is used to
a.
remove O2 from roots.
b.
produce H2O from O2.
c.
deliver O2 to bacteroids.
d.
transport O2 in the xylem.
e.
produce O2 from H2O.
57. A mutant soybean plant that is unable to produce leghemoglobin will most likely suffer from ____
deficiency.
a.
phosphorus
b.
magnesium
c.
potassium
d.
oxygen
e.
nitrogen
58. The enzyme nitrogenase is irreversibly inhibited by excess
a.
O2.
b.
NO3−.
c.
N2.
d.
CO2.
e.
NH4+.
59. Animals trapped and digested by “carnivorous” plants such as the cobra lily are used primarily as
a.
an energy supplement during winter months.
b.
a carbon source for the plant.
c.
a nutrient supplement in nutrient-deficient environments.
d.
food for bacteria and fungi that grow symbiotically with the plant roots.
e.
an energy supplement for small plants growing in shady areas.
60. Haustorial roots of dodders and other nonphotosynthetic, parasitic plants rob the host plant of
a.
sugars.
b.
minerals.
c.
water.
d.
sugars and mineral
e.
sugars, minerals and water
61. Which of the following plants both parasitizes other plants and performs photosynthesis?
a.
snow plant
b.
lady-of-the-night orchid
c.
mistletoe
d.
cobra lily
e.
dodder
62. Epiphytes are
a.
plants that are not parasites but that do grow on other plants instead of the soil.
b.
plants that trap animals and digest them.
c.
parasitic plants that use mycorrhizae to obtain nutrients and food indirectly from other
plants.
d.
plants that deal with nutrient-deficient soil by growing a large, netlike mesh of roots
through several layers of the soil.
e.
parasitic plants that use haustoria to obtain nutrients and food directly from other plants.
63. Farmers often grow legumes such as soybeans every few years and plow much of the plant parts into
the soil. This practice serves mainly to replenish the soil with useful forms of
a.
carbon.
b.
nitrogen.
c.
phosphorus.
d.
oxygen.
e.
manganese.
64. Harrison and van Buuren identified a phosphate transport protein in Glomus versiforme, which is a
a.
carnivorous plant.
b.
bacterium that parasitizes plants.
c.
mycorrhizal fungus.
d.
bacteroid.
e.
parasitic plant.
65. Research by Harrison and van Buuren illustrates how mycorrhizae can reduce the need for applying
a.
nitrogen fertilizer to crops.
b.
potassium fertilizer to crops.
c.
phosphorus fertilizer to crops.
d.
nitrogen fixing plants to soils.
e.
nitrogen fixing bacteria to soils.
66. Plants having the ability to take up organic nitrogen are most likely in which of the following
environments?
a.
arctic tundra
d.
grassland
b.
salt marsh
e.
temperate forest
c.
tropical forest
67. Which of the following disease symptoms would you expect to see in legumes grown in sterile soil?
a.
purplish veins
b.
chlorosis and mottled or bronzed leaves
c.
chlorosis in older leaves and stunted growth
d.
burned leaf edges and curled, mottled, or spotted older leaves
e.
pale green, rolled, or cupped leaves
709
68. Imagine that you are a farmer who chose not to rotate your crops with soybeans even though the local
extension agent recommended that you do so. Which deficiency symptom in your crops should
indicate to you that the extension agent’s advice was correct?
a.
chlorosis and mottled or bronzed leaves
b.
burned leaf edges and curled, mottled, or spotted older leaves
c.
purplish veins
d.
pale green, rolled, or cupped leaves
e.
chlorosis in older leaves and stunted growth
MATCHING
Choice
Choose the appropriate category of general plant nutritional requirement for each element given below.
a.
nonmineral macronutrient
b.
mineral macronutrient
c.
micronutrient
d.
not generally considered an essential nutrient
69. manganese
70. gold
71. oxygen
72. nickel
73. boron
74. sulfur
75. magnesium
76. carbon
77. arsenic
78. calcium
79. iron
80. chlorine
81. lithium
82. zinc
83. potassium
84. molybdenum
85. silver
86. hydrogen
87. phosphorus
88. copper
89. nitrogen
SHORT ANSWER
90. Describe how losing leaves in the autumn can affect plant nutrient requirements, and how plants
handle this issue.
91. What are the most common deficiency symptoms and what process is mostly affected?
92. Why are hydroponics used in mineral nutrition experiments examining essential elements?
93. Why might a soil that has a sufficient concentration of a mineral element, for example, calcium, not
have sufficient availability of the element to maximize plant growth rates?
94. What is the potential significance of root exudates?
ESSAY
95. There are many potential ways to reduce the amount of inorganic fertilizer that is applied to cropland.
If you were to make recommendations on the use of inorganic fertilizer application to a crop, what are
some of the variables and processes you would consider?
96. Nutrients clearly limit the growth of plants. Explain four ways that plants have adapted to increase
access to nutrients and what limits the association from becoming more common.