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Which of the following is currently the most powerful method of research on plant hormones?

analyzing mutant plants

Which one of the following is considered to be an important plant hormone that helps plants cope with environmental stress?

abscisic acid

Which of the following is the role of calcium-dependent protein kinases?

effector molecule

Which of the following is considered to be a plant behavior?

All of the choices

What plant hormones might be used to enhance stem elongation and fruit growth?

auxins and gibberellins

Which one of the following describes a plant's response to heat stress?

production of heat-shock proteins and closing of stomata

Which of the following hormones, produced in the root tips, is (are) required for normal growth?

cytokinins

Which of the following is not presently considered a major mechanism whereby hormones control plant development?

affecting cell respiration via regulation of the citric acid cycle

Which of the following hormones would be most useful in promoting the rooting of plant cuttings?

auxins

Which of the following is a plant behavior that is influenced by light?

ALL of the choices are true

Which of the following have accelerated recent discoveries about the function of plant hormones?

our increased knowledge of development using Arabidopsis, better analysis of signal transduction pathways using mutant plants, and more precise use of molecular biology techniques

Which of the following statements is (are) true of plants?

plants adjust their growth and development in response to environmental cues

Why is it so difficult to study the actions of plant hormones?

all of these make the study of plant hormones hard

When transplanting a tree, it is recommended to loosely attach three or four guylines. The purpose of leaving these supports loose is to

permit moderate bending to stimulate thickness growth

When phytochromes mediate plant reponses to shading they could cause

extension of shade leaves into the light

When an arborist prunes a lumb off a valuable tree, he usually paints the cut surface. The primary purpose of this is

to block entry of pathogens through the wound

When a plant that is not adapted to salty water is exposed to salty water it

will lose water rather than absorb it

What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?

Ca2+ channels could open, and specific protein kinase 2 could still be produced

What do results of research on gravitropic responses of roots and stems show?

the effect of a plant hormone can depend on the tissue

We know from the experiment of the past that plants bend toward light because

cell expansion is greater on the dark side of the stem

If growers want fruit to drop from trees simultaneously they might apply

auxins

If a plant is mechanically stimulated, it will grow shorter, thicker stems. This response is

the result of ethylene production and an adaptation to windy environments

If you were shipping green bananas to a super market thousands of miles away, what chemical would you eliminate?

ethylene

If a producer wants to prevent certain fruits from ripening they would apply

gibberellins

If you take a short-day plant and put it in a lab under conditinos where it will flower (long nights and short days), but interrupt its day period with a few minutes of darkness, what will happen?

it will flower

If a plant is bending towards the light, one would expect which enzymes to have increased activity?

wall-loosening enzymes

Increasing the proportion of unsaturated fatty acids in their membranes is a response of plants to

cold stress

In shoots, branching is inhibited by ____ from the tip of a growing shoot, but this effect is countered by ____ from the roots.

auxin; cytokinins

In order to flower, a short day plant needs a

night that is longer than a certain length

In roots auxins tend to ____ cell elongation, in stems they promote cell elongation.

inhibit

In the autumn, the amount of ____ increases and the amount of ____ decreases in leaf stalks causing a plant to drop fruit and leaves.

ethylene; auxin

In a signal transduction pathway, the transduction stage amplifies the original signal by

having each receptor molecule produce multiple secondary messengers and having each secondary messenger activate numerous specific enzymes

In legumes, it has been shown that "sleep" movements are correlated with

rhythmic opening and closing of K+ channels in motor cells

In order for a plant to initiate a chemical response to herbivory

volatile signal compounds must be recieved

In extremely cold regions, woody species may survive freezing temperatures by

increasing cytoplasmic levels of specific solute concentrations, such as sugars

The results of this experiment, shown on the left of the graph (area A), may be used to

show a correlation between plant height and gibberellins concentration

The production of organic solutes by plants is a response to

salt stress

The best place to find gibberellins in a plant would be in the

all of these are correct

The initial response of the root cells of a tomato plant watered with seawater would be to

begin to pasmolyze as water is lost

The immediate, direct effect of auxin in cell elongation, according to the acid growth hypothesis, is to

activate ATP-driven proton (H+) pumps

The abscission layer

is where a leaf separates from a stem

The formation of air tubes in submerged roots is an adaptation to

oxygen deprivation

The growth response in plants that is related to touch is called:

thigmotropism

The houseplants in a windowless oom with only fluorescent lights begin to grow tall and leggy. Which of the following treatments would promote more normal growth?

add some incandescent bulbs to increase the amount of red light

The plant hormone ethylene has three to four of the following characteristics. Which one, if any, of these features is NOT characteristic of ethylene?

ethylene has all of the above characteristics

The synthesis and release of abscisic acid in a plant is a response to

water deficit

The biological clock controlling circadian rhythms must ultimately

affect gene transcription

The main reason seeds germinate when brought to the soil surface, when the soil is disturbed, might be because

they require light to germinate

The response to touch by such plants as the sensitive plant is due to

changes in water content of cells

The closing of the stomata in leaves is a response by plants to

water deficit

The steps between a plant's perception of a change in the environment and the plants response to that change is best called

signal transduction

The application of which of the following hormones would be a logical first choice in an attempt to produce normal growth in mutant dwarf plants?

gibberellin

This experiment suggests that the unknown amount of gibberellin in the experimental plant (B) is approximately (from figure 39.2)

0.1 ug/mL

Plant hormones can be characterized by all of the following except that they

function independently of other hormones

Plant hormones produce their effects by

altering the expression of genes and modifying the permeability of the plasma membrane

Plants are affected by an array of pathogens. Which of the following is not a plant defense against disease?

all of these are plant defenses against disease

Plants growing in a particularly dark environment will grow toward light in a response called phototropism. Choose the incorrect statement.

auxin causes a decrease in growth on the side of the stem exposed to light

Plant hormones can have different effects at different concentration. This explains how

auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds

Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes

are more predictable than air temperature changes

Plant roots that are in a horizontal position grown down because

cells on the upper side elongate more than those on the lower side

Auxin is responsible for all of the following plant growth responses except

detection of photoperiod

Auxins primarily flow downward in shoots and roots and this transport is called

polar

A pathogenic fungus invades a plant. What does the infected plant produce in response to the attack?

phytoalexins

Alaskan trapper leaves lights on all the time. Plants flower a month early. They are

long day plants

All of the following are responses of plants to cold stress except

conversion of the fluid mosaic cell membrane to a solid mosaic one

A rapid loss of water in specialized cells in the sensitive plant mimosa pudica causes

leaves to droop

A certain short-day plant flowers when days are less than 12 hours long. Which of the following will cause it to flower?

a 13 hour night and an 11 hour day with 1 minute of darkness after 6 hours

A certain plant flowers only if days are shorter than 10 hours. Which of the following will cause it to flower?

8 hours light, 8 hours dark, flash of red light, flash of far-red light, 8 hours dark

A graduate student growing plant cells in a laboratory dish wants to see them ____ so the student treats them with cytokinins.

divide

A chemical change in a substance called phytochrome

enables a plant to respond to the presence of light

A botanist discovers a plant that lacks the ability to form starch grains in root cells, yet the roots still grow downward. This evidence refutes the long-standing hypothesis that

falling statoliths trigger gravitropism

Some seeds require light for germination, which is controlled by the phytochrome system. In which of the following treatments would germination not occur?

red light followed by far-red light

Suppose there is a large deciduous ornamental tree on your campus and the city places a very bright street light right next to it on a tall pole. A botanist on the faculty complains to the city council and asks them to remove the light. Most likely the botanist is concerned because the light

may change the photoperiod and cause the tree to retain its leaves during the winter. This could cause dehydration and loss of the tree.

Secondary messengers are associated with which of the following?

transduction

Short day plants are those that flower only when the night period of a plant is

longer than a defined period

One application of auxins is its use in the production of:

Fruit lacking seeds

One effect of gibberellins is to stimulate cereal seeds to produce

amylase

One of the important roles of ethylene in plant development is that it induces radial swelling in:

root and stem seedling development

Circadian rhythms are

innate 24 hour cycles of behavior or physiological change

Certain plants may form tissues called ____ when their roots are flooded, whereas other plants may always form these tissue types.

aerenchyma

Cytokinins are plant hormones that usually affect cell

division

Changing the solute composition of cells is a response of some plants to

cold stress

Most scientists agree that global warming is underway; thus it is important to know how plants respond to heat stress. Which of the following is an immediate short-term response of plants to heat stress?

the production of heat-shock proteins like those of other organisms

Gravitropism is defined as

growth in response to the force of gravity

External stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the

cell membrane

Ethylene has the effect of causing fruits to

ripen

How are halophytes adapted to salty environments?

they have salt glands that pump salt out of the plant across the leaf epidermis

How are heat-shock proteins thought to work?

they help other proteins retain their functional conformations

Bald cypress and Loblolly pine are both gymnosperm trees native to the southern United States. The cypress grows in swamps; the pine grows in sandy soil. How do you think their anatomies differ?

There are larger intercellular spaces in the roots of the cypress than in the roots of the pine

Both red and blue light are involved in

stem elongation

Biological clocks cause organisms to perform daily activities on a regular basis. Which of the following is a false statement about this kind of circadian rhythm?

Once set, it is independent of external signals

You are interested in determining what part of a plant is actually sensitive to light for phototropism. A good first experiment would be to

Cover one part (for instance, the tip or base) before beginning light treatments

____ appear to be responsible for gravitropism.

Statoliths

Gibbereliins were discovered as a result of

a fungal disease on rice

Which one of the following is most correct concerning plant behavior?

It is influenced by internal factors such as plant regulators.

Which of these conclusions is supported by the research of both Went and Charles and Frances Darwin on shoot responses to light?

A chemical substance involved in shoot bending is produced in shoot tips.

Plant cells begin synthesizing large quantities of heat-shock proteins

when the air around species from temperate regions is about 40 C

Roots contain starch-heavy plastids known as:

statoliths

Which plant hormone(s) is (are) most closely associated with cell division?

cytokinin

Certain plants that grow in environments where their roots are often under water need to provide ways of getting which of the following to the roots?

oxygen

a long-day plant will flower if

the duration of continuous darkness is less than a critical length

Which of the following has not been established as an aspect of auxin's role in cell elongation?

Auxin increases the quantity of cytoplasm in the cell.

abscisic acid is an important signal, transported from roots to the stem and leaves during times of water stress, that prevents:

stomatal opening

Plant defenses against the herbivores that eat them include

all of the above

If you want your plants to branch more, you can spray them with

cytokinins

A directional growth response that results in a change in the position of a plant is called

all the above

The plant hormone that prevents seed germination even if conditions of temperature and moisture conditions are appropriate would be:

abscisic acid

If a short-day plant has a critical night length of 15 hours, then which of the following 24-hour cycles will prevent flowering?

8 hours light/8 hours dark/light flash/8 hours dark

In attempting to make a seed break dormancy, one logically could treat it with

gibberellins

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the

tip of the coleoptile

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