Chapter 5 Quiz

Question 1

Which are the primary ways that light affects a plant?

Select all that apply.

• light reverses plant aging
• light provides energy for photosynthesis
• light determines plant morphology
• light moves plants to increase stem strength

Answer 1

• light provides energy for photosynthesis

- light determines plant morphology

Question 2

Which are characteristics of a shade leaf?

Select all that apply.

• thicker
• smaller
• darker green
• lighter green
• larger
• thinner

Answer 2

• darker green
• larger
• thinner

Question 3

Light is both a _____ which provides different colors of light AND a _____ of energy that excites chlorophyll during photosynthesis.

Answer 3

wave, pulse

Question 4

The wavelengths of the visible spectrum range from _______________ to _____________________.

Answer 4

380 to 770 nm

Question 5

Which of the following is NOT a way that horticulturists measure light?

• quality
• quantity
• actinic
• duration

Answer 5

actinic

Question 6

Which characteristic of light is most often a trigger?

Answer 6

photoperiod

Question 7

_________ are often called accessory or helper pigments because they are excited by light energy and pass that energy to _________ for use in photosynthesis. _________ often intensify under cool nights and warm, bright days and are often responsible for red colors in fall leaves.

Answer 7

carotenoids, chlorophyll a, anthocyanins

Question 8

Why do C4 and CAM plants have an advantage when temperatures are higher?

Answer 8

they don’t experience photorespiration nearly as often

Question 9

Which is NOT a reason to optimize spacing and orientation for plants?

• Decrease photorespiration rates
• Make best use of light
• Increase plant quality
• Help prevent and control disease

Answer 9

-Decrease photorespiration

Question 10

When cauliflower heads are blanched or celery plants are grown very close to one another __________ occurs. The result is tissues that are white or light yellow-green. This happens because __________ breaks down rapidly in the absence of light.

Answer 10

etiolation, chlorophyll

Question 11

Cryptochromes and phototropins are ________ light receptors. They control stem elongation and leaf expansion, circadian rhythms and ________, the bending of plants toward or away from light.

Answer 11

blue, phototropisms

Question 12

Phytochromes are _________ light receptors. They control seed germination, photoperiod, internode elongation and anthocyanin production.

Answer 12

red

Question 13

Plants look green to us because chlorophyll a absorbs a lot of _______ light, but very little _________ light.

Answer 13

green, red and blue

Question 14

A hedge should be…

Answer 14

wider at the bottom than at the top