Deck 37: Plant Nutrition

Question 1

The B horizon of soil is characterized by which of the following?

A) living organisms and decaying organic matter
B) a mixture of broken soil with a variety of texture
C) much less organic matter than the A horizon
D) partially broken-down rock

Answer 1

C

Question 2

Which of the following is not a problem resulting from intensive irrigation?

A) mineral runoff
B) over fertilization
C) aquifer depletion
D) soil salinization

Answer 2

B

Question 3

Which elements are most often the limiting nutrients for plant growth?

A) nitrogen, potassium, phosphorus
B) nitrogen, oxygen, hydrogen
C) carbon, sodium, chlorine
D) carbon, nitrogen, oxygen

Answer 3

A

Question 4

Which criteria allow biologists to classify chemicals into macronutrients and micronutrients?

A) molecular weight of the element or compound
B) the quantities of each required by plants
C) how they are used in metabolism
D) whether or not they are essential for plant growth

Question 5

A group of ten tomato plants are germinated and maintained in a large tray with no drainage. After several weeks they all begin to wilt and die despite repeated watering and fertilization. Which of the following is the most likely cause of the plant death?

A) competition for resources
B) a lack of oxygen for the roots
C) organic nutrient depletion
D) no room left for root growth

Question 6

Soil pH is an important factor that influences which of the following?

A) cation exchange
B) the chemical form of minerals
C) availability of organic matter
D) cation exchange and the chemical form of minerals

Question 7

Soils containing large amounts of which of the following components will provide the least amount of oxygen to growing roots?

A) clay
B) sand
C) humus
D) silt

Question 8

A farmer purchases land in a relatively arid area and is interested in earning a reasonable profit for many decades. 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

Question 9

What does the N-P-K ratio on a package of fertilizer indicate?

A) percentages of manure collected from different types of animals
B) relative percentages of organic and inorganic nutrients in the fertilizer
C) percentages of three important mineral nutrients
D) proportions of three different nitrogen sources

Question 10

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 before and 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 11

Which of the following techniques is not intended to reduce soil erosion?

A) planting rows of trees as windbreaks
B) no-till agriculture
C) terrace hillside crops
D) plowing over stubble immediately after harvest

Question 12

Which of the following is the least disruptive strategy for removing toxic heavy metals from a soil?

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

Question 13

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

A) Na+
B) K+
C) Ca2+
D) NO3-

Question 14

During an experiment to identify essential nutrients, all but one class group observed the effects of micronutrient deficiencies on plant growth. Which of the following is the best explanation for the normal plant appearance in the one outlier group?

A) The discrepant group did not pipette accurately.
B) The discrepant group mislabeled their containers.
C) The discrepant group used tap water instead of deionized (distilled) water.
D) The discrepant group forgot to add micronutrient solution.

Question 15

Which answer best describes how roots acidify the soil solution?

A) Roots release CO₂ and pump K+ into the soil.
B) Roots release CO₂ and pump H+ into the soil.
C) Roots release NaCl and pump Na+ into the soil.
D) Roots release NaCl and pump Cl- into the soil.

Question 16

Which answer best explains how nitrogen deficiency in plants causes chlorosis at the tips of older leaves?

A) Nitrogen is a component of chlorophyll, but it is mobile and is re-located from older leaves to growing parts.
B) Nitrogen is necessary to synthesize chlorophyll in mature areas of older leaves.
C) Nitrogen is a component of all enzymes, so new growth will stop if nitrogen is deficient.
D) Nitrogen regulates proton pumps that supply energy to growing tissue at the tips of older leaves.

Question 17

What soil composition would be best for availability of nutrients, water, and air for root development?

A) equal amounts of sand, clay, and silt
B) higher proportion of silt; lower amounts of clay and sand
C) higher proportion of clay; lower amounts of silt and sand
D) higher proportion of sand; lower amount of silt and clay

Question 18

Which of the following properties is least conducive to plant growth?

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

Question 19

Which one of the following elements plays a critical role in the structure of chlorophyll?

A) magnesium
B) manganese
C) calcium
D) zinc

Question 20

Which of the following soil conditions would inhibit the growth of most plants?

A) abundant humus mixed with loam
B) air spaces in the topsoil
C) poor drainage in the C horizon
D) absence of an A horizon

Question 21

Which of the following is a major function of potassium in plants?

A) regenerate ATP from ADP
B) be a component of DNA and RNA
C) be a component of chlorophyll
D) control guard cell function

Question 22

Which one of the following nutrients plays a critical role as a component of proteins?

A) potassium
B) calcium
C) magnesium
D) sulfur

Question 23

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

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

Question 24

The hyphae of ectomycorrhizae 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

Question 25

Of the following terms, which best describes the ecological role of a Venus flytrap?

A) parasite
B) mutualist
C) epiphyte
D) predator

Question 26

Nitrogen-fixing bacteria and nitrifying bacteria convert atmospheric nitrogen into different compounds of nitrogen such as:
I) ammonium ion
II) ammonia
III) nitrate ion
IV) nitrite ion.
Which of the following is the correct sequence of formation of the nitrogen compounds?

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

Question 27

You are weeding your garden when you accidentally expose some roots of your pea plants, which are legumes like soybeans. You notice swellings (root nodules) on the roots, and there is a reddish tinge to the ones you accidentally damaged. These observations are evidence for which of the following?

A) The peas suffer from a mineral deficiency.
B) The peas are infected with a parasite.
C) The peas are benefiting from a mutualistic bacterium.
D) The peas are developing root buds to form branch roots.

Question 28

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

A) Endomycorrhizae have thicker, shorter hyphae than ectomycorrhizae.
B) Ectomycorrhizae do not penetrate root cells, whereas endomycorrhizae grow into invaginations of the root cell membranes.
C) Endomycorrhizae are more common than ectomycorrhizae.
D) There are no significant differences between ectomycorrhizae and endomycorrhizae.

Question 29

Two groups of tomatoes were grown under laboratory conditions, one with humus added to the soil, and one a control without humus. The leaves of the plants grown without humus were less green compared with those of the plants grown in the humus-enriched soil. Which of the following is the best explanation for this difference?

A) the healthy plants used the food in the decomposing leaves of the humus for energy to make chlorophyll
B) the humus made the soil more loosely packed, so water penetrated more easily to the roots
C) the humus contained minerals such as magnesium and iron, needed for the synthesis of chlorophyll
D) the heat released by the decomposing leaves of the humus caused more rapid growth and chlorophyll synthesis

Question 30

Which of the following best describes the process of nitrogen fixation?

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

Question 31

The earliest vascular plants on land had underground stems (rhizomes), but no roots. Which of the following explains how the plants obtained water and mineral nutrients?

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

Question 32

How does nitrogen fixation lead to enhanced plant growth?

A) Nitrogen fixation enables prokaryotes to supply the plant with proteins directly.
B) Fixed nitrogen can be used by plants to produce protein.
C) Nitrogen fixation directly by the plant is very expensive in terms of metabolic energy.
D) Nitrogen fixation prevents herbivores from eating the plant.

Question 33

Soil leaching can cause nutrient deficiencies in the soil. Which of the following is not a symptom of nutrient deficiency in plants?

A) chlorosis
B) death of meristems
C) excess storage of chlorophyll
D) small internodes

Question 34

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

A) energy
B) carbohydrates
C) lipids and steroids
D) nitrogen and other minerals

Question 35

Which of the following is the most probable cause of a mineral deficiency in a plant after being treated with a fungicide?

A) Mineral receptor proteins in the plant membrane were not functioning.
B) Mycorrhizal fungi were killed.
C) Active transport of minerals was inhibited.
D) Proton pumps reversed the membrane potential.

Question 36

In which of the following environments would we expect the greatest difference in plant health between two groups of plants of the same species, one group with mycorrhizae and the other group without mycorrhizae?

A) where nitrogen-fixing bacteria are abundant
B) soil with poor drainage
C) soil deficient in mineral nutrients
D) near a body of water, such as a pond or river

Question 37

Why are micronutrients needed in only very small amounts?

A) most micronutrients are mobile in the plant
B) most micronutrients serve mainly as cofactors of enzymes
C) micronutrients play only a minor role in the growth and health of the plant
D) only the most actively growing regions of the plants require micronutrients

Question 38

Which of the following is a common feature shared by rhizobial bacteria, actinomycete bacteria, and cyanobacteria?

A) They increase water uptake in plants.
B) They kill parasites in the soil.
C) Each exists only in extreme environments.
D) Each fixes atmospheric nitrogen.

Question 39

If garden tomatoes display chlorosis, which of the following fertilizers would likely reduce this symptom?

A) 10-0-0
B) 0-10-0
C) 0-0-10
D) 0-0-0

Question 40

Which 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 water and phosphorus, and fungi receive photosynthetic products.

Question 41

Epiphytes are ________.

A) fungi that attack plants
B) fungi that form mutualistic associations with roots
C) nonphotosynthetic parasitic plants
D) plants that grow on other plants

Question 42

The inorganic nutrient most often lacking in crops is ________.

A) carbon
B) nitrogen
C) phosphorus
D) potassium

Question 43

A problem with intensive irrigation is ________.

A) overfertilization
B) aquifer depletion
C) the long-term depletion of soil oxygen
D) the clogging of waterways by vegetation debris

Question 44

Mycorrhizae enhance plant nutrition mainly by ________.

A) absorbing water and minerals through the fungal hyphae
B) providing sugar to root cells, which have no chloroplasts
C) converting atmospheric nitrogen to ammonia

Question 45

The greatest difference in health between two groups of plants of the same species, one group with mycorrhizae and one group without mycorrhizae, would be in an environment ________.

A) where nitrogen-fixing bacteria are abundant
B) that has soil with poor drainage
C) that has hot summers and cold winters
D) in which the soil is relatively deficient in mineral nutrients

Question 46

Two groups of tomatoes were grown under laboratory conditions, one with humus added to the soil and one a control without humus. The leaves of the plants grown without humus were yellowish (less green) compared with those of the plants grown in humus-enriched soil. The best explanation is that ________.

A) the healthy plants used the food in the decomposing leaves of the humus for energy to make chlorophyll
B) the humus made the soil more loosely packed, so water penetrated more easily to the roots
C) the humus contained minerals such as magnesium and iron needed for the synthesis of chlorophyll
D) the heat released by the decomposing leaves of the humus caused more rapid growth and chlorophyll synthesis

Question 47

The specific relationship between a legume and its mutualistic Rhizobium strain probably depends on ________.

A) each legume having a chemical dialogue with a fungus
B) each Rhizobium strain having a form of nitrogenase that works only in the appropriate legume host
C) each legume being found where the soil has only the Rhizobium specific to that legume
D) specific recognition between chemical signals and signal receptors of the Rhizobium strain and legume species

Question 48

Micronutrients are needed in very small amounts because ________.

A) most of them are mobile in the plant
B) most serve mainly as cofactors of enzymes
C) most are supplied in large enough quantities in seeds
D) they play only a minor role in the growth and health of the plant

Question 49

A mineral deficiency is likely to affect older leaves more than younger leaves if ________.

A) the mineral is a micronutrient
B) the mineral is very mobile within the plant
C) the mineral is required for chlorophyll synthesis
D) the mineral is a macronutrient

Question 50

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

A) If the plant is green, it is epiphytic.
B) The root of an epiphytic plant will be in the soil.
C) The roots of a parasitic plant will penetrate through the bark into the xylem.
D) The epiphytic plant will have large water collecting leaves.

Question 51

Which of the following best describes epiphytes?

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