Environmental Constraints Flashcards
Three categories of resources to grow and produce fruit. What is it called when they dont get these three things?
- Water
- Carbon
- Nutrients
In sub-optimal growing conditions they undergo environmental stress
Discuss the idea of stress is good for quality?
When people say this they really have no idea with they are talking about. Stresses adversely affect plant growth, development, and productivity.
Discuss what can happen with carbon deficiencies and what can happen with nutrient deficiencies?
Carbon limitations can cause an increase in partitioning to the shoots
Nutrient deficiencies typically increase root growth.
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.
acclimation processes
Finish the sentence from your notes: 50% of seasonal dry matter should be partitioned to the clusters…
If you have less than this ripening is uncertain.
What is the difference between a source and a sink?
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
When is a leaf a sink and when it is a source?
Leaves younger than 10 days are sinks
Leaves older than 10 days are sources
List 2 Sources and 5 sinks of a plant
Sources:
- Adult leaves
- Reserves
Sinks:
- Immature leaves
- Fruits
- Stems
- Roots
- Reserves
What is sink strength
It is sink size x sink activity
(in the picture from class the tip of the shoot has the greatest sink strength)
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
- From April to May the majority of energy is being sent upward towards the shoot tip.
- In June some of the energy starts getting sent down to the clusters
- Then in August there is another shift in which now there is a proportion of energy being sent to permanent organs.
- 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
What are the two stress hormones?
Auxin and cytokinins
A low auxin ratio stimulates
shoot growth over root growth
A high auxin ratio stimulates
lateral root grown and results in shorter shoot internodes and smaller leaves, but probably higher apical dominance.
Which hormone is responsible for root growth and which hormone has the opposite effect?
Auxin
cytokinins
What are the first signs of chilling injuries? (3)
- Swelling of the chloroplast
- Distortion of thylakoid membranes
- Starch Depletion
How cold of temperatures can a vine withstand?
15 Degrees C
What can the vines do under prolonged exposure to low temperature?
Vines activate an organized cell suicide process
Cold nights seem to make the leaves more susceptible to…
High light intensity
__________ can trigger anthocyanin accumulation in the exterior leaves of red- skinned cultivars so that the leaves might turn red.
Photo-oxidative stress
The acclimation to low temperature, termed _______________, is very similar to the photoacclimation to high light intesity and both processes aim to _____________.
- chilling acclimation
- limit photo-inhibition.
What is Supercooling?
- The process by which water will not freeze even if temperature is below freezing point
What freezes first and what can this lead to?
Apoplast freezes first then the symplast. Apoplast is the vascular system so water stress and freezing effectively dehydrate the symplast (via water deficit)
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
➢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)
What are the two main worries of frost damage?
- What will happen to this year’s crop
- What will happen to next year’s crop
Does starch increase cold hardiness of canes?
NO
Which woody organ is most sensitive to freeze damage?
The Phloem
What temperature is v. vinifera generally killed at?
-25 degrees C
