Environmental Constraints

Question 1

Three categories of resources to grow and produce fruit. What is it called when they dont get these three things?

Answer 1

1. Water
2. Carbon
3. Nutrients

In sub-optimal growing conditions they undergo environmental stress

Question 2

Discuss the idea of stress is good for quality?

Answer 2

When people say this they really have no idea with they are talking about. Stresses adversely affect plant growth, development, and productivity.

Question 3

Discuss what can happen with carbon deficiencies and what can happen with nutrient deficiencies?

Answer 3

Carbon limitations can cause an increase in partitioning to the shoots

Nutrient deficiencies typically increase root growth.

Question 4

Depending of the severity and duration of a stress event and on the rate at which it starts and end, stress can trigger ___________ in the entire vine.

Answer 4

acclimation processes

Question 5

Finish the sentence from your notes: 50% of seasonal dry matter should be partitioned to the clusters…

Answer 5

If you have less than this ripening is uncertain.

Question 6

What is the difference between a source and a sink?

Answer 6

A source is an organ that is able to synthesize or reallocate sugar toward the sinks.

A sink is an organ that is growing and attracting sugar

Question 7

When is a leaf a sink and when it is a source?

Answer 7

Leaves younger than 10 days are sinks

Leaves older than 10 days are sources

Question 8

List 2 Sources and 5 sinks of a plant

Answer 8

Sources:
- Adult leaves
- Reserves

Sinks:
- Immature leaves
- Fruits
- Stems
- Roots
- Reserves

Question 9

What is sink strength

Answer 9

It is sink size x sink activity

(in the picture from class the tip of the shoot has the greatest sink strength)

Question 10

There is a graph from class showing the energy allocation from April to October, please describe the trend of this graph and any relevant information

Answer 10

1. From April to May the majority of energy is being sent upward towards the shoot tip.
2. In June some of the energy starts getting sent down to the clusters
3. Then in August there is another shift in which now there is a proportion of energy being sent to permanent organs.
4. As the graph flows in essentially a logistic trend, the energy above the curve gets sent upward (diminishing over time) the energy under the curve gets sent to the clusters (increasing over time) and then there is a steady proportion of that energy from under the curve that gets sent to the permanent organs

Question 11

What are the two stress hormones?

Answer 11

Auxin and cytokinins

Question 12

A low auxin ratio stimulates

Answer 12

shoot growth over root growth

Question 13

A high auxin ratio stimulates

Answer 13

lateral root grown and results in shorter shoot internodes and smaller leaves, but probably higher apical dominance.

Question 14

Which hormone is responsible for root growth and which hormone has the opposite effect?

Answer 14

Auxin

cytokinins

Question 15

What are the first signs of chilling injuries? (3)

Answer 15

1. Swelling of the chloroplast
2. Distortion of thylakoid membranes
3. Starch Depletion

Question 16

How cold of temperatures can a vine withstand?

Answer 16

15 Degrees C

Question 17

What can the vines do under prolonged exposure to low temperature?

Answer 17

Vines activate an organized cell suicide process

Question 18

Cold nights seem to make the leaves more susceptible to…

Answer 18

High light intensity

Question 19

__________ can trigger anthocyanin accumulation in the exterior leaves of red- skinned cultivars so that the leaves might turn red.

Answer 19

Photo-oxidative stress

Question 20

The acclimation to low temperature, termed _______________, is very similar to the photoacclimation to high light intesity and both processes aim to _____________.

Answer 20

1. chilling acclimation
2. limit photo-inhibition.

Question 21

What is Supercooling?

Answer 21

1. The process by which water will not freeze even if temperature is below freezing point

Question 22

What freezes first and what can this lead to?

Answer 22

Apoplast freezes first then the symplast. Apoplast is the vascular system so water stress and freezing effectively dehydrate the symplast (via water deficit)

Question 23

Place the inter-row management options in order from warmest to coldest

➢ High cover crop
➢ Cut grass and wet soil
➢ Bare, wet soil, no tillage
➢ Short cover crop, wet soil
➢ Recently tilled soil
➢ Bare soil, dry soil, no tillage

Answer 23

➢Bare, wet soil, no tillage (the warmest)
➢Cut grass and wet soil (1-2 °C colder)
➢ Short cover crop, wet soil (1-3 °C colder)
➢Bare soil, dry soil, no tillage (2 °C colder)
➢ Recently tilled soil (2 °C colder)
➢ High cover crop (2 – 4 °C colder)

Question 24

What are the two main worries of frost damage?

Answer 24

1. What will happen to this year’s crop
2. What will happen to next year’s crop

Question 25

Does starch increase cold hardiness of canes?

Answer 25

NO

Question 26

Which woody organ is most sensitive to freeze damage?

Answer 26

The Phloem

Question 27

What temperature is v. vinifera generally killed at?

Answer 27

-25 degrees C