Chapter 2 - The Vine Growth Cycle Flashcards
1
Q
What are the two main seasons that make up the vine growth cycle?
A
- Growing season
- Dormancy
2
Q
In which months does dormancy occur in the Northern Hemisphere?
A
November to March
3
Q
In which months does dormancy occur in the Southern Hemisphere?
A
May to September
4
Q
What temperature is generally considered too cold for vine growth?
A
Below 10°C (50°F)
5
Q
What temperature can severely damage or kill dormant vines?
A
- Below -20°C (-4°F) can cause severe damage
- Below -25°C (-13°F) will kill most Vitis vinifera
6
Q
What marks the end of winter dormancy?
A
Budburst
7
Q
What are the two primary requirements for budburst?
A
- Average air temperature above 10°C (50°F)
- Soil temperature above 10°C (50°F)
8
Q
During which season is winter pruning carried out?
A
During dormancy
9
Q
Name four grape varieties considered “early budding”.
A
- Chardonnay
- Pinot Noir
- Merlot
- Grenache
10
Q
Name three grape varieties considered “late budding”.
A
- Sauvignon Blanc
- Cabernet Sauvignon
- Syrah
11
Q
Why might grape growers delay winter pruning in frost-prone areas?
A
To postpone budburst and reduce the risk of frost damage
12
Q
What happens to vines during dormancy with no leaves?
A
They sustain themselves using stored carbohydrates (mainly starch) from the previous growing season
13
Q
Where are carbohydrates stored in the dormant vine?
A
- Roots
- Trunk
- Branches
14
Q
In which months does budburst occur in the Northern Hemisphere?
A
March to April
15
Q
In which months does budburst occur in the Southern Hemisphere?
A
September to October
16
Q
Name two adverse conditions for budburst.
A
- Frost
- Cold soils
17
Q
What two resources initially support shoot growth after budburst?
A
- Stored carbohydrates from the previous growing season
- Photosynthesis as leaves develop
18
Q
Name four factors that can cause low carbohydrate levels in vines.
A
- Excessive leaf removal in previous season
- Water stress in previous season
- Mildew infections in previous season
- Excessively high yields in previous season
19
Q
What type of climate is advantageous for uniform budburst and why?
A
Continental climate, because rapidly increasing temperatures in spring promote synchronous budburst
20
Q
What type of soils warm up more quickly and can be beneficial in cool climates?
A
Dry, free-draining soils such as sandy soils
21
Q
Why is uniform budburst desirable?
A
It leads to homogeneity in later growth stages, promoting even ripeness
22
Q
What are the three primary nutrient requirements of vines during shoot and leaf growth?
A
- Nitrogen
- Potassium
- Phosphorus
23
Q
What is the term used to describe vegetative vine growth?
A
Vigor
24
Q
What are the months for shoot and leaf growth in the Northern Hemisphere?
A
March to June
25
What are the months for shoot and leaf growth in the Southern Hemisphere?
September to December
26
Name three factors that influence vine vigor.
1. Available natural resources (temperature, water, nutrients)
2. Planting material (grape variety, clone, rootstock)
3. Presence of disease
27
What four negative effects can stunted shoot growth cause?
1. Small, weak shoots
2. Reduction in leaf number/smaller leaves
3. Improper flowering of inflorescences
4. Grape bunches that don't ripen fully
28
What happens to the vine's energy focus before and after flowering starts?
Before flowering: energy directed toward shoot growth
After flowering starts: energy shifts toward reproductive growth
29
In which months does flowering and fruit set occur in the Northern Hemisphere?
May to June
30
In which months does flowering and fruit set occur in the Southern Hemisphere?
November to December
31
What are the two key climatic requirements for flowering in grapevines?
1. Warm temperatures (minimum 17°C/63°F)
2. Sunlight for bud fruitfulness in the next growing season
32
What four adverse conditions can negatively impact flowering?
1. Rainy conditions
2. Cloudy conditions
3. Windy conditions
4. Cold temperatures
33
Name three structures developed from fertilized ovules in grape flowers.
1. Seeds
2. Skin
3. Pulp
34
What is the typical timing of flowering after budburst?
Within eight weeks of budburst
35
What percentage of flowers typically become grapes during fruit set?
Typically 30% (range from 0-60%)
36
What is the minimum temperature needed for successful flowering?
17°C (63°F)
37
What is the optimal temperature range for pollen germination during fruit set?
26-32°C (79-90°F)
38
What is coulure?
A condition where fruit set fails for a high proportion of flowers resulting in reduced yields
39
Name three causes of coulure.
1. Cold, cloudy conditions reducing photosynthesis
2. Hot, arid conditions causing water stress
3. Vigorous shoot growth diverting carbohydrates
40
Name four grape varieties particularly susceptible to coulure.
1. Grenache
2. Cabernet Sauvignon
3. Merlot
4. Malbec
41
What is millerandage?
A condition where there is a high proportion of seedless grapes which are smaller than grapes with seeds
42
What conditions can cause millerandage?
Cold, wet, windy weather at fruit set
(Also boron deficiency and Fanleaf degeneration as per Oxford companion)
43
Name two grape varieties more susceptible to millerandage.
1. Chardonnay
2. Merlot
44
What is self-pollination and why is it important for grapevines?
Self-pollination is when pollen from the stamens of one flower is transferred to the stigma of the same flower or another flower on the same plant. Research shows cultivated varieties of vines are normally self-pollinating, with little contribution from insects or wind.
45
What is the impact of cold temperatures on flowering duration?
Cold temperatures lengthen the duration of flowering
46
In which months does grape development occur in the Northern Hemisphere?
June to September
47
In which months does grape development occur in the Southern Hemisphere?
December to March
48
What are the four stages of grape development?
1. Early grape growth
2. Véraison
3. Ripening
4. Extra-ripening
49
Name three environmental needs during grape development.
1. Sunlight
2. Warmth
3. Mild water stress
50
Name three adverse conditions for grape development.
1. Too much water and nutrients
2. Excessive shading of grapes
3. Very cold or very hot conditions throughout day and night
51
What is véraison?
The stage when grapes begin changing color (in black varieties) and begin to soften as ripening begins
52
What compounds accumulate during early grape growth?
1. Tartaric acid
2. Malic acid
3. Some aroma compounds and precursors
4. Tannins
53
What are methoxypyrazines and which grape varieties are known for them?
Methoxypyrazines contribute to herbaceous aromas/flavors in wines from Sauvignon Blanc, Cabernet Sauvignon, and Cabernet Franc
54
How does mild water stress during early grape growth affect grape quality?
It can lead to smaller grapes with greater skin-to-pulp ratio, potentially improving quality in red wines (more color, tannins, and aroma compounds)
55
What happens to chlorophyll during véraison?
Green-colored chlorophyll in skin cells is broken down
56
What compounds give black grapes their red color during véraison?
Anthocyanins
57
What happens to the grape cell walls during véraison?
They become more stretchy and supple
58
What happens to the two main acids during ripening?
1. Tartaric acid: concentration falls through dilution
2. Malic acid: concentration falls through dilution and metabolism
59
Which acid is metabolized during ripening and affected by temperature?
Malic acid
60
Why do cool-climate wines tend to have higher natural acidity?
Respiration (which metabolizes malic acid) is slower at cool temperatures
61
What mean temperature in the final month of ripening leads to rapid loss of acidity?
Above 21°C (70°F)
62
What mean temperature in the final month of ripening can result in acidity levels that are too high?
Below 15°C (59°F)
63
What temperature range is optimal for photosynthesis in vines?
18-33°C (64-91°F)
64
What light levels are required for maximum photosynthesis?
Above one-third of full sunshine
65
How does the rate of sugar accumulation change during the ripening stage?
Very rapid at the start, then slows toward the end
66
What causes sugar accumulation to slow in very hot and dry conditions?
Vine will close stomata to stop water vapour lose. This will slow/pause photosynthesis and the producion of sugars. It will also mean the flow of sugar solution in the xylem is slowed or halted.
67
What climate feature helps retain acidity while allowing sugar development?
High diurnal range (warm days cool nights)
68
Name two wine regions with high diurnal range that produce wines with higher acidity.
1. Central Otago
2. Washington State, USA
69
What happens to methoxypyrazine levels during ripening?
They decrease (unless cool temperatures or limited sunlight hinder this process)
70
Name two factors that can hinder the decrease of methoxypyrazines.
1. Cool temperatures
2. Limited sunlight (due to excessive shading or cloud cover)
71
What are terpenes and what aromas do they contribute?
Terpenes give floral and citrus aromas, such as the grapey aromas found in Muscat
72
What happens to tannins during ripening in black grapes?
They polymerize (combine into larger molecules) becoming less bitter
73
What role does sunshine play in tannin development?
1. Pre-véraison: promotes tannin accumulation
2. Post-véraison: promotes greater polymerization
74
What temperature range is optimal for anthocyanin development?
15-25°C (59-77°F)
75
Name three types of transport tissue in vines and their roles.
1. Xylem: transports water and nutrients from roots
2. Phloem: transports sugars from leaves
3. Cambium: produces new xylem and phloem cells
76
How does the method of water transport to grapes change during ripening?
Early growth: mainly via xylem
During ripening: water flow via xylem slows, replaced by sugar solution via phloem
77
How does grape transpiration affect sugar accumulation?
Higher transpiration (in warm, dry conditions) increases sugar accumulation
78
Name two early ripening grape varieties.
1. Chardonnay
2. Pinot Noir
79
Name two late ripening grape varieties.
1. Cabernet Sauvignon
2. Grenache
80
What grape variety is particularly prone to uneven ripening?
Zinfandel
81
Name three factors that can slow down ripening.
1. High yields
2. Excessive shading within the vine canopy
3. Actively growing shoots
82
What are the four key parameters that determine grape ripeness?
1. Sugar levels
2. Acidity levels
3. Aroma/flavor profile
4. Tannin ripeness
83
Why do warm climate wines often have higher alcohol levels?
Sugar ripens faster than aromas and tannins so grapes are picked with higher sugar levels
84
What happens during the extra-ripening stage?
1. Grapes start to shrivel
2. No more sugar imported via phloem
3. Water loss concentrates existing sugars
4. Extra-ripe aromas develop
85
What happens to vine shoots in late summer?
They lignify (become woody and rigid) and are then called canes
86
What happens to the vine after harvest in autumn?
1. Leaves fall
2. Carbohydrate reserves are laid down in roots, trunk and branches
3. Vine enters dormancy
87
What grape variety is particularly susceptible to shriveling during extra-ripening?
Syrah
88
What climatic conditions favor grape shriveling?
Hot, sunny, dry conditions
89
Why might a winemaker choose not to allow extra-ripening on the vine?
1. Weather conditions
2. Disease pressure
3. Desired wine style
90
How does high diurnal temperature range affect acid retention?
Cool night temperatures reduce the metabolism of malic acid during respiration
91
How does the ripeness of aromas change as grapes develop?
From underripe/herbaceous to fresh fruit to riper fruit, and even jammy or cooked
92
What is the relationship between tannin bitterness and polymerization?
As tannins polymerize during ripening bitterness will be reduced.
93
What happens to sugar levels if harvest is delayed into the extra-ripening stage?
Sugar becomes more concentrated due to water loss through grape transpiration
