The Vine Growth Cycle

Question 1

What are the changes in the vine after harvest?

Answer 1

• Late summer, green shoots become lignify( woody and rigid)

Lignify = verhouten

Green shoots became canes

• In autumn leaves fall, carbohydrate reserves are laid down in the vine

Question 2

Dormancy of the vine

Answer 2

November / March N - May / September S

• Vine needs temperature bellow 10° C
• Not when extremely cold – 20° C (-25 ° C all vitis vinifera dies)
• Unusually mild temperatures

Question 3

What is happening during Véraison?

Answer 3

• Grape growth slows down for a few days (lag phase)
• Grape cell walls become more stretchy and supple
• Green colored chlorophyll in skin is broken
• Black varieties become red = anthocyanins

Sunshine on grapes before véraison accumulates tannines in grape, after véraison accumulates polymerisation.

Question 4

What do you know about the pollination (bestuiving)

Answer 4

• These pollen goes in the stigam and goes in the Pollen tube to the ovule were it fertiles the egg in The ovary
• The ovary become the grape. The fertiles egg become the pepin
• Vines are selff fertilazers, wind and insect make little contribution
• Conditions fruitset
  
  • 30% will become grapes (can go from 0 to 60%)
  • Pollentube growth negativ by cold, rainy and windy. Hot and dry = water stress

Question 5

What is grape development and give the 4 stages

Answer 5

June / October N - December / April S

• Vine needs sunlight, warmth, mild waterstress
• Adverse conditions, too much water and nutrients, excessive shading of grapes, verry cold or hot condition during day and night

Stages:

1 Early grape growth

2 Véraison

3 Ripening

4 Extra ripening

Question 6

Budburst depends on?

Answer 6

March / April N - September / October S

• Vine needs temperature above 10° C.

- Frost and Cold Soils

Depends on:

• Air temperature
  
  • Continental climate in advantage (goes quick)

Uniformity and homogeneity in growing and ripening potential

• Maritime climate budburst less synchronized
• Soil temperature
  
  • Higher soil temperatures = earlier budburst such as dry soils warmer up quicklier (advantaged in cool regions)
• Grape variety
  
  • Some are quick (merlot, chardonnay, pinot noir and grenache)
  • Some are late (sauvignon blanc, cabernet sauvignon and syrah)
• Less change for spring frost*
• Not always a link with ripening (example grenache is late ripening)
• Human Factors
  
  • Late winter pruning = delays budburst = spring frost

Question 7

Shoot and leaf growth

Answer 7

March / July N - September / January S

• Vine needs stored carbohydrates, warmth, sunlight, nutrients and water
• Not Low carbohydrates (previous growing season) and water stress
• If carbohydrates are to low in roots of previous year (caused by excessive leaf removal, water stress, mildew, to high yields) shoot grow will be negative affected*
• Developed Leaves provide energy for further growth (photosynthesis)*

Question 8

Extra ripening if grapes are legt on the vine:

Answer 8

• Grape starts to shrivel (verschrompelen)
• No more water and sugar imported bij the phloem
• Water lost by transpiration > sugar
• Developing extra ripe aromas
• Most in dry hot sunny climats
  
  • Depends on the grape (syrah susceptible)

Question 9

What is happening during early grape growth?

Answer 9

• Starts After fruit set
• Tartaric and malic acids accumulate
• Tannin accumulate (verry bitter)
• Sugar verry low
• Water transported by the xylem (transport tissue from roots to vines and berries)
• Aroma compounds aroma precursors (compounds with no aroma that will become aroma during the fermentation example methoxypyrazines)
• Too much water and nutrients can prolong (vigorous of the shoots will increase)
• Mild water stress can increase stadium leading to smaller berries = more concentration
• Shoot grows continues more slowly

Question 10

Lengt of grape ripening depends on:

Answer 10

• Grape variety

early ripening ex. Chardonnay an PN

late ripening ex cabernet sauvignon

some are uneven ripening such as zinfandel and chenin blanc

• Climate conditions

Quicker in hot climates (can be different when watterstress closes photosynthesis)

• Management of vine and vineyard

Still mucht growing of canopy slows down ripening

Shading within the vine

• Time of harvest depends on human factors (weather, style, logistics)

Question 12

What do yoy know about flowering and fruitset

Answer 12

May / June N - November / December S

• Vine needs warm temperatures (+17° C), sunlight, warmth, water and nutients for bud fruitfulness in next growing season
• Adverse conditions, rainy, cloudy, windy and to cold temperatures
• Conditions flowering
  
  • 8 weeks after budburst (earlier in warm condition)
  • 17° C. Warm condition 2 days, cold conditions few weeks

Question 13

Wat is Coulure and Millerandage

Answer 13

• Coulure = high proportion flowers with no fruitset

= imbalance in carbohydrate levels

• By low rates of photosynthesis
  
  • Cold, cloudy conditions
  • Hot arid condition by waterstress
• By to vigorous shoot growth
  
  • Diverting carbohydrates to the flower
  • To fertile soils = to much shoot vigour
• Grape varity (grenache, cabernet sauvignon, merlot and malbec)
• Millerandage = high proportion of seedless grapes
  
  • Because cold wet and windy weather
  • Grape varity (chardonnay and merlot)
  • Verry small = Reduces yields
  • Somthimes stay very green

Question 14

Shoot and leaf growth depends on:

Answer 14

• Natural resources available
• Planting material (grape variety, clone and rootstock)
• Presence of any disease
• As vine grows, needs nutrients (nitrogen N stikstof , potassium K calium and phosphorus P fosfor)
• No water stress (because the vine does not get his nutrients)
• Problem with verry dry soils
• Stunted growth (vertraagde groei) lead to small shoot, less inflorescences, les photosynthesis and less ripening = poor quality and yields

Question 15

What is happening during ripening?

Answer 15

• Shoot growth falls down
• Cells in grape expand rapidly
• Sugar and water accumulate
• Acid level falls
• Sugar accumulation, hights in the beginning slows down to the end
• Photosynthesis between 18° C en 33° C.and min. 1/3 sunshine
• Tartric accid doesn’t fall down, only grape gets more wather and sugar.
• Malic accid goes down, beacause it metabolised (omgezet) bij resperation of the leaves. This goes quicker by high temperature (above 21°C) in the final month of ripening. Accid lowers and PH rises.

Region with cool night tempertures can have more accidety

Temperature above 21° C in the last month of ripening can lead to rapid loss of aciditylevels and under 15° C can lead to to high levels of malic accidity

• Methoxypyrazine levels fall (cool areas and shaded place have more)
• Athor aroma reprecursors are increasing such as terpens (flowers and lime in muscat) by rippening
• Tannins are very high by veraison and decreases slightly by rep

They polymerse (kleine moleculen binden zich tot grote ketting, worden daardoor minder bitter)

• Sunshine on grapes before véraison accumulates tannines in grape, after véraison accumulates polymerisation.
• Anthocyanins increases during ripening stage. Most with a plentiful sunlight and temperature between 15° en 25° C.