D1.C2. The Vine Growth Cycle Flashcards

1
Q

What is the aim of a grape grower?

A

To produce the largest possible crop of grapes that are of suitable ripeness and quality for the style of wine being produced.

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2
Q

Dormancy period is between which months?

A

November-March in northern hemisphere

May-September in southern hemisphere

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3
Q

Under what temperature, the vine goes dormant?

A

Air temperatures below 10°C (50°F)

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4
Q

How does the vine sustain itself during the dormancy?

A

By using the carbohydrates, mostly starch, accumulated during the previous season in the roots, trunk and branches

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5
Q

What are the adverse conditions which might affect vines during dormancy?

A
  • Unusually high temperatures
  • Extreme cold temperatures. Vines can be severely damaged or killed by temperatures below −20°C (–4°F). Temperatures below −25°C (−13°F) will kill most V. vinifera
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6
Q

Budburst period is between which months?

A

March-April in northern hemisphere
September-October in southern hemisphere

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7
Q

What does the vine need during the budburst?

A

Average air and soil temperatures above 10°C (50°F)

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8
Q

What are the adverse conditions which might affect vines during budburst?

A
  • Frosts
  • Cold soils
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9
Q

What kind of regions are advantageous for successful budburst?

A

Regions that have marked differences in temperature between the various seasons (for example, continental climates)

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10
Q

What are the disadvantages of maritime climates during budburst?

A
  • Due to less contrast between winter and spring temperatures budburst can be less synchronised.
  • Unusually mild winter days cause early budburst; any cold days and frosts that follow can potentially harm the newly burst buds, leading to lower yields
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11
Q

Why are free draining soils like sand advantageous in cool climates?

A

They tend to warm up more quickly than water-storing soils, such as clay-rich soils, and therefore growing
season starts early which improves the chance of ripening

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12
Q

Name 4 early budding grape varieties

A
  • Chardonnay
  • Pinot Noir
  • Merlot
  • Grenache
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13
Q

Name 3 late budding grape varieties

A
  • Sauvignon Blanc
  • Cabernet Sauvignon
  • Syrah
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14
Q

Name one human factor which can delay the budburst, and its aim

A
  • Carrying out winter pruning late in the dormant period
  • To avoid spring frost
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15
Q

Shoot and leaf growth period is between which months?

A
  • March–July in the Northern Hemisphere
  • September–January in the Southern Hemisphere
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16
Q

What does the vine need during the shoot and leaf growth?

A
  • Stored carbohydrates
  • Warmth
  • Sunlight
  • Nutrients
  • Water
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17
Q

What are the adverse conditions which might affect vines during shoot and leaf growth?

A
  • Low carbohydrate levels (caused by conditions in the previous growing season)
  • Water stress
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18
Q

What does “vine vigour” refer to?

A

Vegetative vine growth, which includes the growth of the shoots, leaves and lateral shoots, and has implications on the yield and ripening of the grapes

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19
Q

Name the factors that affect the vine vigour?

A
  • Natural sources available (temp, water, nutrients)
  • Planting material (variety, clone and rootstocks)
  • Presence of any disease
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20
Q

What are the reasons for low carbohydrate levels in a vine?

A
  • Excessive leaf removal
  • Water stress
  • Mildew infections
  • Excessively high yields in the previous growing seasons
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21
Q

Why is water stress is disadvantageous during shoot and leaf growth?

A
  • It can limit photosynthesis and shoot growth
  • Nutrient uptake through the roots is also impaired in very dry soils
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22
Q

Flowering and fruit set period is between which months?

A
  • May–June in the Northern Hemisphere
  • November–December in the Southern Hemisphere
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23
Q

What does the vine need during the flowering and fruit set?

A
  • Warm temperatures (minimum 17°C/63ºF)
  • Sunlight, warmth, water and nutrients for bud fruitfulness in the next growing season
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24
Q

What are the adverse conditions which might affect vines during flowering and fruit set?

A
  • Rain
  • Cloudy weather
  • Windy weather
  • Cold temperatures
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25
Q

What are the factors that can limit bud fruitfulness in the following season?

A
  • Shading of the compound buds
  • Low temperatures (under 17°C/77ºF)
  • Water stress
  • Nutrient deficiency
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26
Q

Why is Riesling well-suited to cool climates?

A

It is able to form potentially fruitful buds at relatively low temperatures

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27
Q

What is “pollination”?

A

The pollen grains are shed from the anthers of the stamens and land on the moistened stigma surface

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28
Q

How are the pollen tubes produced?

A

By germination of pollen grains in stigma surface

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29
Q

How are the sperm cells delivered to the ovary?

A

By pollen tubes which penetrate the stigma and then the ovule

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30
Q

What does the ovule and the ovary give rise to when fertilized?

A
  • Ovule: Seeds (up to 4)
  • Ovary: Skin and the pulp of the grape
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31
Q

What does “fruit set” term denote?

A

The transition from flower to grape

32
Q

Do the cultivated vines need other vines to pollinate?

A
  • No, they are normally self-pollinating
33
Q

Flowering typically occurs within how many weeks of budburst?

A

8 weeks

34
Q

What is the most important factor that affect the flowering?

A

Temperature (minimum temperature of 17°C / 63°F)

35
Q

How long does the flowering last, if the temperature is ideal?

A

Within a few days

36
Q

Typically, how many percent of flowers become grapes

A

It can range from 0 to 60% but it is typically 30 %

37
Q

What is the optimal temperature range for pollen germination?

A

26–32°C / 79–90°F

38
Q

Which factors negatively affect the pollen tube growth, which can result in irregular fruit set?

A
  • Cold
  • Rain
  • Wind
39
Q

What is coulure?

A

A condition of the grape bunch in which fruit set has failed for a high proportion of flowers

40
Q

What is the main cause of coulure?

A

Imbalance in carbohydrate levels

41
Q

What are the reasons for imbalance in carbohydrate levels, resulting into coulure?

A
  1. Low rate of photosynthesis
    - Cold cloudy conditions
    - Hot, arid conditions with high water stress
  2. Vigourous shoot growth
    - Very fertile soils
    - Heavy applications of fertilizers
    - Vigourous rootstocks
42
Q

Which grape varieties are also naturally more susceptible to coulure than others?

A
  • Grenache
  • Cabernet Sauvignon
  • Merlot
  • Malbec
43
Q

What is millerandage?

A

A condition of the grape bunch in which there is a high proportion of seedless grapes

44
Q

Why does millerandage negatively affect the wine quality?

A

Because seedless grapes stay small, green and unripe

45
Q

What is the reason for millerandage?

A

Cold, wet, windy weather at fruit set

46
Q

Which varieties are more susceptible to millerandage?

A

Chardonnay and Merlot

47
Q

Grape development period is between which months?

A

June–October in the Northern Hemisphere, December–April in the Southern Hemisphere

48
Q

What are the stages of grape development?

A
  1. Early grape growth
  2. Veraison
  3. Ripening
  4. Extra-ripening (optional)
49
Q

What does the vine need during grape development?

A
  • Sunlight
  • Warmth
  • Mild water stress
50
Q

What are the adverse conditions which might affect vines during grape development?

A
  • Too much water and nutrients
  • Excessive shading of grapes
  • Very cold or very hot conditions throughout the day and night
51
Q

What kind of acids begin to accumulate during early grape growth?

A
  • Malic acid
  • Tartaric acid
52
Q

What is the effect of sunshine on tannin accumulation?

A

It promotes tannin accumulation

53
Q

What is the effect of too much water and nitrogen during early grape growth?

A

It can prolong this stage since they encourage shoot growth in preference to grape ripening

54
Q

What is the effect of mild water stress during early grape growth?

A

It can speed up this stage and lead to the production of smaller grapes, reducing juice yield but leading to greater skin to pulp ratio, which in red wines can be associated with better quality

55
Q

Why is veraison is called the lag phase?

A

Because the grape growth slows down for a few days

56
Q

What are the changes in grapes during ripening stage?

A
  • Cells in the grape expand rapidly
  • Sugar and water accumulate
  • Acid levels fall
  • Tannins, colour and a number of aroma precursors and aroma compounds develop
57
Q

Between which temperatures, is the photosynthesis at maximum rate?

A
  • 18–33°C (64–91°F)
58
Q

What changes occur in the transport system during ripening phase?

A
  • Water flow via the xylem slows down
  • Sugar solution (a mixture of mainly sugar and water) is transported to the grape by the phloem
59
Q

Movement of the sugary solution from the phloem into the grape, and hence the sugar accumulation within the grape is correlated to …

A

The rate of grape transpiration

60
Q

Grape transpiration is faster in which weather conditions?

A

Warm and dry conditions

61
Q

What happens to the tartaric acid during ripening?

A

The total amount of tartaric acid does not change, however its concentration falls, due to dilution as the as the sugar and water accumulate

62
Q

Why does the concentration of malic acid decrease more than tartaric acid during ripening?

A

Because malic acid can be metabolized in respiration during ripening phase.

63
Q

Why do the wines from cooler climates have higher acidity?

A

Because the respiration is slower at cool temperatures so malic acid is less metabolized

64
Q

After which mean temperature during the final month of ripening, loss of acidity is high?

A

21°C (70°F)

65
Q

Below which mean temperature during the final month of ripening, loss of acidity is very low, resulting a must with too much acidity levels?

A

15°C (59°F)

66
Q

Which conditions affect the methoxypyrazine levels during ripening?

A

Cool temperatures and limited sunlight ( e.g. due to excessive shading of bunches or cloud cover) can hinder the decrease of methoxypyrazine levels resulting in wines with herbaceous aromas/flavours

67
Q

What happens to the aroma precursors like terpenes during ripening?

A

They increase

68
Q

What happens to level of tannins during ripening?

A

Although the sunshine on the grapes promotes tannin accumulation pre-véraison, during ripening it helps
polymerisation of the tannins which make the tannins less bitter

69
Q

What is the optimal temperature range for the anthrocyanins to accumulate during ripening?

A

15°C (59°F) to 25°C (77°F)

70
Q

The length of ripening stage depend on which factors?

A
  1. Grape variety: Chardonnay and P. Noir are early ripening whereas Grenache and C. Sauvignon are late ripening grapes
  2. Climatic conditions: Quick in warm and dry conditions
  3. Management of vine and vineyard: High yields and excessive shading slow down ripening
  4. Time of harvest
    - Human factors: Desired wine style, logistics
    - Natural factors: Weather, disease
71
Q

How do the sugar levels increase if the grapes are left on the wine?

A

Although no more sugar or water are imported to the grape by the phloem at this stage, the water loss in the grape through grape transpiration lead to increased concentration of sugars

72
Q

When the shoots lignify they are called as…

A

Canes

73
Q

What changes occur in the vine in autumn?

A

Leaves fall, carbohydrate reserves are laid down in the roots, trunk and branches, and the vine enters its dormant period

74
Q

What are the key parameters that determine ripeness

A
  • Sugar level
  • Acidity
  • Profile of aromas/flavours
  • Tannins
75
Q

Which one of the parameters determining ripeness, is oppositely affected by the growing environment when compared to others?

A

Acidity. Falling most quickly in warm, dry climates

76
Q

Why many grape growers focus on attaining the desired level of tannin and aroma ripeness rather than sugar, alcohol and acid levels?

A

Because it is easier to adjust sugar, alcohol or acid levels than to work with grapes that have unripe tannins
and/or aromas