Chapt. 14 Development and Morphogenesis

The plants in the accompanying diagram are biennial plants; the blocked in portion was exposed to cold, freezing temperatures. Which of those plants will be vernalized?

1

Which of the plants will flower if the blocked area is exposed to short-days?

2, both branches of 4

If the phloem sap of a plant was analyzed on a very hot, dry summer day, it would probably contain a higher than normal concentration of

Abscisic acid

If you know in advance that a field will be temporarily flooded, an application of what hormone might help the plants survive?

Abscisic acid

Which of the following is an incorrect match between hormone and function?

Abscisic acid - releases buds from dormancy

Coleus plants can be propagated through stem cuttings if they are placed in a medium containing rooting powder, a form of

Auxin

If all of the fruits (seeds) on the outside of a strawberry are removed when it is young, it will not develop. If the strawberry is sprayed with a hormone solution, normal development occurs. The hormone most likely to cause a response is

Auxin

The first plant hormone discovered was

Auxin

Plant auxins

Bind to receptor molecules to elicit a response

You could induce vernalization in a beet plant by exposing which plant part to cold temperatures?

Buds

In temperate regions, the main way plants detect seasons of the year is through

Day length

A piece of mica is inserted in the tip of a grass coleoptile and the seedling is exposed to unilateral light as shown in the accompanying diagram. In response, the coleoptile

Does not bend because auxin cannot be redistributed

Many fruits are harvested before they are ripe because it is easier to transport them in that stage of development. They must be transported in a partial vacuum mainly to

Draw out ethylene that will hasten ripening

Many plants flower in response to a change in day length. Plants with this adaptation probably have evolved in all of the following areas except

Equatorial Africa

The only plant hormone that is a gas is

Ethylene

Seeds of many temperate region plants break dormancy due to

Exposure to cold temperatures + a photomorphogenic response

A plant grows normally if exposed only to blue light, which can be used in photosynthesis.

False

A stem responds to unilateral light at the site of auxin production.

False

All animal hormones are either steroids or proteins. The same is true in plants.

False

Because plants can neither hear, see nor smell, they cannot respond to external stimuli.

False

Cells all respond the same way to the presence of a hormone in the environment around them.

False

Cells of a vertical stem and a rhizome show the same tropic response to gravity.

False

If an oat coleoptile is grown in the dark, then briefly illuminated with red light from one side, it will bend toward the light source.

False

If immature stem cells are exposed to high levels of auxin, they stop enlarging.

False

In most cases, hormones are synthesized at their place of effect.

False

Like animal hormones, plant hormones are either protein or steroid molecules.

False

Only compounds produced naturally by plants can influence plant growth.

False

Root growth responds to gravity, therefore gravity is necessary for root growth.

False

The endogenous rhythms in a pine tree change from summer to winter.

False

The time a plant or plant part needs to be exposed to an environmental stimulus to elicit a response is the same for all plants.

False

If the rate of auxin transport is measured in a stem segment that has been turned upside-down as in the accompanying diagram, it is found that the movement is

From A to B and occurs at the normal rate

If seeds of a biennial plant, such as beet, are planted in Hawaii, the plants will

Grow vegetatively, but will not flower at all due to high temperatures

The most common long-term response of a plant part to environmental stimuli is

Growth

A plant with a mutation for phototropin would

Have a lower than normal rate of photosynthesis

If the site of perception of an environmental stimulus is a leaf, then the site of transduction is a

Leaf

A plant is a short-night plant whose critical night length is 10 hours. To flower that plant must receive

Nights shorter than 10 hours

The position of bean plant leaves is different at noon and at midnight. This change in position is probably influenced by changing

None of the above

The apical meristem of an actively growing woody stem is removed. If a mixture of paste and gibberellin is applied to the stem tip, cells produced by the vascular cambium will differentiate into

Phloem

If a flower opens at night and closes during the day, the response is

Photonastic

Flowers of night-blooming cereus are open at night and closed during the day. This is an example of a

Photonastic response

The principal pigment involved in photoperiodism and endogenous rhythms is

Phytochrome

If plants are kept in the dark, they have elongated internodes, making them spindly. This effect is due to

Phytochrome in the Pr form

If you want to produce a bushier shrub with more branches, you should

Pinch off the stem tips

Plant growth is least influenced by

Position of the moon

The structure in mosses that produces an egg releases a chemical as it matures that attracts the flagellated sperm produced in a different structure. This is an example of

Positive chemotaxis

If a plant shoot grows too large, the root system cannot adequately supply it with water and minerals. This does not happen because the

Roots produce cytokinins

If the apical meristem of a woody stem is removed, all of the following would stop except

Secondary phloem cell differentiation

If a plant is placed in a horizontal position the

Shoot bends upward due to increased auxin on the lower side

At most plant nurseries, you can buy rooting powder that stimulates root development on stem cuttings. The rooting powder most likely contains

Synthetic auxins

If the top of a woody stem is removed

The leaching of phosphate from the soil

? In general, a plant's response to external stimuli is much slower than the response of an animal.

True

A short-day plant will flower if given 16 hour days followed by 16 hour nights.

True

After a plant zygote divides, the daughter cells become different from each other.

True

In nature, a circadian rhythm is exactly 24 hours long.

True

In some plants, axillary buds start to grow if the auxin/cytokinin ratio decreases.

True

Once a young leaf has perceived the correct night length, the information is conveyed to the stem tip by a chemical messenger.

True

Phytochrome exists in two different forms. Which form is present depends on the wavelength of light absorbed.

True

Red light can "reset" an endogenous rhythm, such as the "sleep" movement of Oxalis leaves.

True

Responses to external stimuli are faster in animals than in plants.

True

The different parts of a terrestrial plant live in different microenvironments.

True

The lack of muscle tissue in plants is adaptive because muscle tissue requires a lot of energy to build.

True

The main response elicited by auxin on a young stem cell is the weakening of its cell wall, enabling the cell to enlarge.

True

The role of hormones is to enable plant parts to communicate with each other.

True

To respond to a particular hormone, a cell must have the appropriate receptors.

True

Tomato fruits become redder if left on a windowsill to ripen rather than in a closet.

True

Vines exhibit a positive thigmotropic response if they encounter a fence post.

True

In response to external conditions, plants

a. Are more resilient than animals b. Use less energy to build response mechanisms than animals c. Have sophisticated response mechanisms for sexual reproduction e. a, b and c

Hormones usually

a. Are produced at one site and act at a different site b. Are effective in very low concentrations c. Bind to receptor molecules located in a receptor cell plasma membrane d. Activate programs in receptor cells e. All of the above

To differentiate into the correct type of mature plant cell, an unspecialized cell in a meristem might be influenced by

a. Chemicals from other cells b. Its position c. Cell enlargement e. a, b, and c

If a plant produced a lower than normal supply of auxin

a. It would be bushier b.Would not have as much xylem differentiation c. Its stems would not bend toward a window e. a, b, and c

If a bulb is planted, its orientation does not matter because the

a. Root grows downward due to positive gravitropism b. Shoot grows upward due to negative gravitropism d. a and b

Ethylene stimulates

b. Conversion of starch to sugars c. Breakdown of cell walls e. b and c