Lecture 2

Question 1

What is agronomy

Answer 1

the application of science and technology from the fields of biology, chemistry, economics, ecology, soil science, water science, pest management and genetics to the improvement and management of the major food crops of the world.

Question 2

Major Agronomic cereal crops

Answer 2

wheat, barley, oats, rye; rice, corn, millet

Question 3

Major Agronomic break crops

Answer 3

pulses (field beans/peas), oilseed rape

Question 4

Major Agronomic horticultural crops

Answer 4

potatoes, field vegetables

Question 5

Major Agronomic protected crops

Answer 5

salads, tomatoes, peppers, berries

Question 6

Major Agronomic forage crops

Answer 6

maize, legumes (clover, beans), root crops (turnip, swede, beets)

Question 7

Name the external (environmental) facts that affect plant growth and development

Answer 7

• Light (quantity and quality)
• CO2
• O2
• Temperature
• Water
• Minerals (macro and micro)
• pH

Question 8

Name the internal factors that affect plant growth and development

Answer 8

• Photosynthesis
• Photoperiod
• Transpiration
• Respiration

Question 9

Who is responsible for the law of the minimum

Answer 9

Justice von Liebig

Question 10

Name the limiting factors for plant growth and development

Answer 10

• Light (quantity and quality)
• CO2
• O2
• Temperature
• Water
• Minerals (macro and micro)

Question 11

What is absence of light known as

Answer 11

Etiolation

Question 12

Low intensity light (mostly red wavelengths)

Answer 12

Causes long spindly growth

Question 13

High intensity light (mostly UV wavelengths)

Answer 13

Causes plant dwarfing

Question 14

What is photosynthetically active radiation in nm

Answer 14

400-700nm

Question 15

What does PAR stand for

Answer 15

photosynthetically active radiation

Question 16

What does photoperiod regulate

Answer 16

Time of flowering
Cessation of vegetative growth
Seed germination
Elongation of seedlings
Fruiting in some species

Question 17

How is photoperiodism regulated

Answer 17

By phytochromes (photoreceptor pigments) that detect red and far red light

Question 18

When does chrysanthemums form flower buds

Answer 18

When day length is <14.5 hours

Question 19

When does further development into open flower occur in chrysanthemums

Answer 19

When day length is <13 hours

Question 20

All plants that respond to daylength contain what pigment

Answer 20

Phytochrome C

Question 21

Loss of Phytochrome C resulted in how many day delay in wheat flowering under long days

Answer 21

108 days

Question 22

Functions of stomata

Answer 22

Photosynthesis
CO2 uptake
Evaporative cooling
Resistance to phytotoxic gases

Question 23

Contribution of CO2-induced reduction in stomatal transpiration to global run-off since when

Answer 23

1960

Question 24

Increase CO2 means what for terrestrial

Answer 24

Increased runoff ,erosion and nutrient leaching

Question 25

Increased CO2 means what for aquatic area

Answer 25

Increased eutrophication , anoxia and toxicity

Question 26

Why can concentration of CO2 temporarily fall outdoors

Answer 26

if planting is too dense, so photosynthesis stops

Question 27

CO2 falls dramatically under cover especially when plants are actively growing how can this be rectified

Answer 27

By ventilating, or in cold weather, leave glasshouse closed and pump in up to 3 times the normal atmospheric concentration of CO2

Question 28

What is oxygen required for

Answer 28

aerobic respiration cell repair reproduction growth

Question 29

What effect does decreasing O2 have

Answer 29

decreases respiration

Question 30

<15% [O2] means what for reproduction

Answer 30

It is reduced

Question 31

<2.5% [O2] means what for reproduction

Answer 31

It fails

Question 32

0% [O2] causes what to take place

Answer 32

Anaerobic respiration

Question 33

Anaerobic conditions in flooded soil can lead to what in plant roots

Answer 33

Ethanol toxicity (alcohol poisoning)

Question 34

What is temperature important for in plants

Answer 34

cell structure and function and in regulating rate of transport within the plant

Question 35

Plant enzymes operative best at what temperature

Answer 35

at ~25 degrees Celsius

Question 36

Too low of a temperature has what affect

Answer 36

membranes not fluid, affecting transporters

Question 37

Too high of a temperature has what affect

Answer 37

Membranes disintegrate and plant dies

Question 38

Activity for the photosynthesis cycle (Calvin Cycle) increase between what temperature

Answer 38

0 and 36 degrees Celcius

Question 39

Why is temperature control in glasshouses critical

Answer 39

To avoid thermal damage

Question 40

Name the most important compound in the biological world

Answer 40

Water

Question 41

Water has the greatest single influence on what in climate

Answer 41

Heat sink and source Precipitation Rising sea levels

Question 42

What is the role of water in plants

Answer 42

• Essential component in photosynthesis • Responsible for turgor pressure in cells:controls growth (internal skeleton) • Solvent for minerals and CHO movement • Controls stomatal opening and closing • Cools leaves via latent heat of vaporisation

Question 43

Under drought conditions do plants open or close their stomata

Answer 43

Close it

Question 44

Disadvantages of drought conditions

Answer 44

• No CO2 intake so photosynthesis stops • No minerals brought in via roots up through plant so so biochemical processes cannot proceed • Plant cannot regulate temperature so thermal damage occurs

Question 45

What causes viscosity of water to vary

Answer 45

Temperature

Question 46

When temperature INCREASES what happens to viscosity

Answer 46

It decreases

Question 47

Viscosity of H20 is how many times more great at 0 degrees as it is at 25 degrees

Answer 47

Twice as great

Question 48

Why does Cold water taken up by the plant in spring move more slowly in the vascular system than it does in summer / early autumn

Answer 48

Due to higher viscosity The problem is when air is warm and windy

Question 49

What causes leaf scorch

Answer 49

when the soil is cold and the evaporating power of the atmosphere is high (because it contains warm dry air)

Question 50

When may leaf scorch occur

Answer 50

Early spring

Question 51

Name the central atom of Chlorphyll

Answer 51

Magnesium

Question 52

Name the MACRO nutrients

Answer 52

N, P, K, S, Ca, Mg (NO PAUL KILLED SEAN CIAN MICHAEL)

Question 53

Name the MICRO nutrients

Answer 53

Fe, Mn, B, Cu, Zn, Mo, Cl, Ni (FUNNY MAN BUYS COKE ZEBRAS MILK CAKE NAPPIES )