PSC 1800 Exam 2 USU

Which are the primary ways that light affects a plant?

light determines plant morphology

light provides energy for photosynthesis

Which are characteristics of a shade leaf?

Darker green

Thinner

Larger

Light is both a _____ and a ______

wave and pulse

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

380 to 770 nm

Which ways do horticulturists measure light?

Duration

Quantity

Quality

Which characteristic of light is most often a trigger?

Photoperiod

____________ 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.

Carotenoids

Chlorophyll a

anthocyanins

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

They don't experience photorespiration nearly as often

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

Decrease photorespiration rates

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.

etiolation

chlorophyll

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

Blue

phototropism

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

Red

Plants look ______ because chlorphyll absorbs a lot of ______ and _______ but very little _______ light

Green

Red and Blue

Green

A hedge should be...

Wider at the bottom than at the top

Plant growth slows or stops

0c (32f)

Proteins are denatured or destroyed

50c (122f)

Generic Min threshold for Warm season plants

10 c (50f)

Generic Min threshold for cool season plants

5c (40f)

Which of the following is the most correct statement about temperature and the rate of chemical processes?

As temperature increases, the rate of chemical reactions increases until a maximum temperature where the relationship breaks down.

Most plant growth occurs ____ because the _______ close and the _______ increases

at night

stomates

turgor pressure

light compensation point

photosynthesis = respiration

light saturation point

point where light is no longer the limiting factor in photosynthetic rates

DIF

day temp - night temp

Even though manipulating DIF is effective in controlling plant height, it is not commonly used because it requires too much energy to do.

True

The best red fall colors occur when days are _____ and nights are _____ because ______ rates exceed ________ rates and the excess sugars increase the production of _________

Bright and warm

Cool

Photosynthesis

Respiration

Anthocyanins

The most energy-efficient greenhouse design _____________

Minimizes the surface area to volume ratio

Number of hours between 0 and 7 C (32 and 45 F) required for floral initiation and flowering

Chilling hours

State of rest where a seed/plant will not germinate/grow even if conditions are favorable

Dormancy

Moist cold treatment for seeds that simulates winter and breaks dormancy

Stratification

Cold treatment for a certain period of time required for some plants to flower properly

Vernalization

Which of the following is NOT a way to conserve energy in a greenhouse or controlled environment?

Replace your old air conditioning unit

Quality of light

Wave lengths

Quanntity of light

How bright

Measured in Photosynthetic photon flux

Duration

Photoperiod

Carotenoids

Protect chloroplasts

Transfer energy to chlorophyll a

Blue light is responsible for

Stem elongation

Circadian rhythms

Phototrophisms

Red light

Photoperiod

Germination

Gene Expression

Triggers Anthocyanin

Carotenoids reflect

yellow, red-orange light

Day neutral plants

Bloom as long as they are matured

Long day plants

Short nights (Summer flowering)

Short day plants

long night

Fall flowering

Cold hardiness zone is based off

Average annual minimum temps

Heat zones

Based on number of days above 86*

Temperature _______ affects the rate of ___________ ___________

Directly

Chemical Reactions

GGD

Minimum + max/ 2 - minimum threshold

Ways to prevent freezing

Sprinklers

Fires

Wind machines

Row covers

Sugar is for _______ term storage and starch is for _________ term storage

Short

Long

Glass = best _______

worst ________

Light transmission

insulations

Double layer polyethylene

Cheap

Good insulator

Worst light transmission

Soil temps affect

Germinations

Root growth

Plant devolpment

Most crops need _____ hours of sun

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