2. The Vine Growth Cycle Flashcards
(94 cards)
1
Q
What factors are important for the vine to produce grapes suitable for making wine?
A
heat, sunlight, water, nutrients, and the timings of these key resources within the growth cycle.
2
Q
Name the stages of a vine growth cycle. Put them into appropriate order.
A
- Dormancy (November–March in the Northern Hemisphere, May–September in the Southern Hemisphere)
- Budburst
March–April in the Northern Hemisphere, September–October in the Southern Hemisphere - Shoot and Leaf Growth
March–July in the Northern Hemisphere, September–January in the Southern Hemisphere - Flowering and Fruit Set
May–June in the Northern Hemisphere, November–December in the Southern Hemisphere - Grape Development
June–October in the Northern Hemisphere, December–April in the Southern Hemisphere
3
Q
When does winter dormancy start and end?
A
With leaf fall in the autumn (November) and ends with budburst in the spring (March).
4
Q
What average air temperatures are too cold for the vine to grow?
A
Below 10°C
5
Q
How does the vine support its growth when it cannot photosynthesise?
A
By using stores of carbohydrates, mostly starch.
6
Q
Where are the nutrients accumulated during the previous growing season?
A
In the roots, trunk and branches.
7
Q
Define bud burst.
A
the process, when buds swell and open, and green shoots start to emerge..
8
Q
What does the timing of budburst depend on?
A
AIR TEMPERATURE
SOIL TEMPERATURE
GRAPE VARIETY
HUMAN FACTORS
9
Q
What average air temperature is needed for budburst?
A
10°C
10
Q
Why can regions that have MARKED differences in temperature between the various seasons be ADVANTAGEOUS for successful budburst?
A
rapidly increasing temperatures in the spring =>
budburst can be relatively uniform =>
the homogeneity of later stages in the growing season =>
a crop of grapes with even ripeness.
11
Q
In what regions can bud burst be less synchronized?
A
In regions where there is often less contrast between winter and spring temperatures (for example, maritime climates.
12
Q
Why can DRY, free-draining soils (sandy soils) compared to water-storing soils (clay-rich soils) be ADVANTAGEOUS in cool climates for bud burst and ripening?
A
They tend to warm up more quickly than water-storing soils. Higher soil temperatures around the roots => earlier budburst.
An early start to the growing season=> better ripening.
13
Q
Define early budding grape varieties.
A
Varieties that require relatively LOW temperatures at budburst.
14
Q
Give examples of EARLY budding grape varieties.
A
Chardonnay, Pinot Noir, Merlot and Grenache.
15
Q
Define late budding grape varieties.
A
Grape varieties that require HIGHER temperatures at budburst.
16
Q
Give examples of LATE budding grape varieties.
A
Sauvignon Blanc, Cabernet Sauvignon and Syrah.
17
Q
What viticultural practices can delay budburst?
A
winter pruning late in the dormant period
18
Q
Define inflorescences.
A
a cluster of flowers on a stem.
19
Q
What determines the vigour of the vine?
A
The rate of shoot growth.
20
Q
When does the fastest rate of growth occur?
A
Between budburst and flowering.
21
Q
Is the speed of shoot growth the same for all vines and in all parts of the vine?
A
No. It can vary between vines and within different parts of the same vine.
22
Q
How is the initial shoot growth supported?
A
By carbohydrates stored in the roots, trunk and branches.
23
Q
What can decrease the level of carbohydrates storage?
A
Excessive leaf removal,
water stress,
mildew infections,
high crop loads in the previous growing season.
24
Q
What do leaves need for successful photosynthesis and growth?
A
Warmth and sunlight.
25
Where to is most of the vine’s energy directed until flowering starts?
Towards shoot growth.
26
What nutrients are needed for vine growth?
Nitrogen (N),
potassium (K),
phosphorus (P).
27
What can limit photosynthesis and shoot growth?
- water stress
- dry soils around the roots
- low carbohydrate levels (caused by conditions in the previous growing season)
28
What are the effects of stunted (slowed) shoot growth?
small, weak shoots =>
reduction in leaf number or smaller leaves =>
inflorescences that do not flower properly =>
grape bunches that do not ripen fully =>
poor quality and lower yields.
29
What does the vine need during shoot and leaves growth?
- Stored Carbohydrates
| - Warmth, sunlight, nutrients and water
30
Define bud fruitfulness.
the number of inflorescences that will develop from a bud.
31
What can limit bud fruitfulness?
Shading of compound buds,
low temperatures (under 25°C),
water stress,
nutrient deficiency.
32
Define flowering.
the opening of the individual flowers within an inflorescence.
33
Name the parts of the vine flower.
```
Stamen — тычинка (Anther — пыльник + Filament — волосок, тычиночная нить)
Pollen — пыльца
Stigma — рыльце пестика
Pollen tube - пыльцевая трубка
Ovule — семязачаток, семяпочка; яйцева клетка
Egg
Ovary — маточник, завязь; яичник
Germination — проращивание, всхожесть
Penetrate - проникать
```
34
Describe the initial stage of flowering.
The pollen-laden stamens (consisting of an anther and filament) are exposed.
35
Describe the pollination.
The pollen grains are shed and land on the moistened stigma surface.
36
How is ovule fertilized? Describe a grape berry formation.
On the moistened stigma surface pollen grains germinate, with each pollen grain producing a pollen tube.
These pollen tubes penetrate the stigma and then the ovule (the female reproductive cells) in the ovary.
The pollen tube delivers the sperm cells, which fertilise the eggs in the ovule. This leads to the formation of a grape berry.
37
How are seeds formed?
The fertilised ovules form seeds.
38
How many seeds are there per grape?
Up to 4 seeds per grape.
39
How are skin and pulp formed?
The wall of the ovary enlarges to form the skin and pulp of the grape.
40
Define a fruit set.
Transition from flower to grape.
41
How are cultivated varieties of vines dissiminated?
Self-pollinating (the pollen from the stamens of one flower is transferred to the stigma of the same flower, or a different flower in the same plant).
42
Within what period does flowering typically take place?
Within eight weeks of budburst.
43
What conditions are favourable for successful flowering?
Warm conditions (minimum temperature of 17°C ) => quick (a few days) and even flowering.
44
What conditions are UNfavourable for successful flowering?
Low temperatures => lengthen the duration of flowering (weeks) => uneven flowering.
45
Do all flowers become grapes?
No.
46
How many flowers become grapes?
0-60%, typically 30%.
47
What t is optimal for pollen germination and pollen tube growth ?
26–32°C
48
What are negative factors affecting fruit set?
- cold, rainy and/or windy conditions;
| - hot, dry, windy conditions => water stress.
49
Define coulure.
A condition of the grape bunch in which fruit set has failed for a high proportion of flowers.
50
When does coulure occur?
This occurs when ovule fertilisation is unsuccessful, and therefore no grape develops.
51
What is coulure caused by?
By an imbalance in carbohydrate levels.
52
What is an imbalance in carbohydrate levels caused by?
```
cold, cloudy conditions;
hot, arid conditions with high water stress;
vigorous shoot growth;
Very fertile soils;
heavy application of fertilisers;
vigorous rootstocks.
```
53
Which grape varieties are susceptible to coulure?
Grenache, Cabernet Sauvignon, Merlot and Malbec.
54
Define millerandage.
A condition of the grape bunch in which there is a high proportion of seedless grapes.
55
How is millerandage manifested?
Seedless grapes stay small, green and unripe.
56
What are the effects of millerandage?
reduce the volume of wine;
| reduce wine quality.
57
What does millerandage result from?
cold, wet, windy weather at pollination and fruit set
58
Which grape varieties are susceptible to millerandage?
Chardonnay and Merlot.
59
What stages is grape development typically split into?
1. GRAPE BERRY FORMATION
2. VÉRAISON
3. RIPENING
4. EXTRA-RIPENING
60
What compound are accumulated as green grapes start to grow in size?
acids (tartaric and malic),
aroma compounds and aroma precursors,
tannins (bitter at this time),
sugar levels (low)
61
Define aroma precursors.
compounds with no aroma that will become aroma compounds during the fermentation process.
62
Define methoxypyrazines.
Methoxypyrazines contribute to herbaceous aromas/flavours in some wines, such as those made from Sauvignon Blanc, Cabernet Sauvignon and Cabernet Franc.
63
Define the xylem.
a type of transport tissue that transfers water and some nutrients from the roots to other parts of the vine.
64
What factors can prolong grape berry formation?
Too much water and nitrogen, as these factors encourage shoot growth in preference to grape ripening.
65
What negative and positive effect can water bring to grape berry formation?
-a delay in the onset of the ripening stage => not sufficient time for ripening before the weather becomes cold and rainy;
+ Mild water stress can speed up this stage and lead to the production of smaller grapes, reducing juice yield but leading to greater skin to pulp ratio => higher levels of colour, tannins and aroma compounds in red wines.
66
What is the lag phase?
When grape growth slows down for a few days before veraison.
67
Describe VÉRAISON.
The grape cell walls become more stretchy and supple => green-coloured chlorophyll in skin cells is broken down => grapes of black varieties become red in colour (due to the synthesis of anthocyanins).
68
Define anthocyanins.
Anthocyanins are the most important natural colourants in wine grapes. Anthocyanins are a group of naturally occurring phenolic-compounds that are responsible for the red, purple and blue colours found in many fruits, vegetables and wine grapes.
They belong to a parent group of molecules called flavonoids; they are odourless and virtually have no flavour, contributing to taste a moderately astringent sensation.
69
What happens to the main compounds during grape ripening?
The cells in the grape expand rapidly, sugar and water accumulate and acid levels fall.
Tannins, colour and a number of aroma precursors and aroma compounds develop.
70
Describe sugar accumulation during ripening.
Sugar accumulation is very rapid at the start of the ripening stage and then slows towards the end. Sugar is produced in the vines’ leaves by photosynthesis. Photosynthesis can take place at a maximum rate at temperatures between 18–33°C (64–91°F) and at sunlight levels that are above one third of full sunshine. Therefore, in years with cold weather or constant cloud, rate of photosynthesis may hinder sugar levels in the grapes. By contrast, very hot, dry conditions that can lead to extreme water stress can cause photosynthesis to slow or stop (see The Effects of Water) and hence hinder sugar accumulation in this way.
71
What are the conditions for photosynthesis to happen at a maximum rate?
Temperatures between 18–33°C (64–91°F) and at sunlight levels that are above one third of full sunshine.
72
Define the phloem.
a type of transport tissue that transfers sugars from the leaves to other parts of the vine.
73
What is the sugar accumulation within the grape correlated to?
to the rate of grape transpiration.
74
What is grape transpiration?
Grapes do not have stomata and do not transpire as much as leaves, but a small amount of water can transpire through the grape skin.
75
When is the grape transpiration faster/slower?
grape transpiration and therefore sugar accumulation is faster in warm, dry conditions than cool, humid conditions.
76
What risks do warm conditions bring to the sugar accumulation?
In warm conditions, this accumulation of sugar can be too rapid and reach high levels before aromas/flavours and tannins have developed fully.
77
Does the total amount of tartaric acid in the grape change?
No.
78
What happens to the concentration of tartaric acid (винная) during ripening? Why?
The concentration falls during ripening due to dilution, as sugar and water accumulate in the grape.
79
What happens to the concentration of malic acid (яблочная) during grape ripening? Why?
It falls even further than that of tartaric acid.
Because malic acid can be used in respiration during the ripening stage (before this point, sugar is used in respiration).
80
Define respiration.
the process in which energy is released from food substances (ex, sugar).
81
Why do wines from cooler climates tend to have higher natural acidity?
Respiration is slower at cool temperatures than warm ones.
| Cool night time temperatures also mean that less malic acid is lost during respiration.
82
Why warm areas with a high diurnal range (Central Otago, Washington State) can produce wines with higher acidity than those with warmer night time temperatures?
Mean temperatures above 21°C (70°F) in the final month of ripening can lead to a rapid loss of acidity (and a rise in pH),
mean temperatures below 15°C (59°F) can reduce acid loss to a point that acidity levels in the must are too high.
83
What happens with methoxypyrazine levels during ripening?
Methoxypyrazine (herbaceous aromas/flavours) levels fall.
84
Why can wines may show particularly herbaceous aromas/flavours?
Cool temperatures and limited sunlight (e.g. due to excessive shading of bunches) can hinder this decrease of methoxypyrazine levels during ripening.
85
What aromas do terpenes give?
floral and citrus aromas such as the grapey aromas found in Muscat.
86
What's the dynamic of the levels of tannins throughout veraison to ripening?
What makes tannins polymerization?
levels of tannins are high at véraison and decrease slightly throughout ripening.
During ripening, tannins polymerise and become less bitter.
87
What's the dynamic of the levels of anthocyanins throughout veraison to ripening?
Anthocyanins increase during the ripening stage, and increase most rapidly with plentiful sunlight and temperatures between approximately 15°C (59°F) and 25°C (77°F).
88
What factors does the length of the ripening stage depend on?
* Grape variety
* Climatic conditions
* Management of the vine and vineyard
* Time of harvest
89
Describe EXTRA-RIPENING stage.
Grapes left on the vine start to shrivel (вянуть).
No more sugar or water are imported to the grape by the phloem at this stage, but water loss in the grape through grape transpiration means that sugars are concentrated. Extra-ripe aromas can also develop in this stage.
90
What are the key parameters that determine ripeness?
The level of sugar
The profile of the aromas/flavours in the grapes
Tannin ripeness (red wine)
91
What is considered as optimal ripeness?
the time at which the combination of the sugar, tannin and aroma ripeness is at its most favourable.
92
When do green shoots lignify (become woody and rigid)?
In late summer.
93
Define the canes.
The green shoots from the previous growing season that have lignified (have turned brown and woody).
94
What happens to the vine in autumn?
leaves fall, carbohydrate reserves are laid down in the roots, trunk and branches and the vine enters its dormant period.
