Ch 2 The Vine Growth Cycle Flashcards
What is the purpose of grapes
Animals and birds eat and spread seeds
What are the main processes/functions of the vine and what do they need?
- light, warmth, water + C02 (out of WM control) -for photosynthesis
2.warmth for respiration (energy is released in form of sugar) - Nutrients - for cell and vine function/growth
What are the phases of vine growth and when do they occur?
Leaf fall/Dormancy: Nov - Mar/May-Sep
Budburst: Mar-Apr/Sep-Oct
Leaf and shoot growth: Mar - June/Sep -Dec
Flowering and fruitset: May-June/Nov-Dec
Grape development: June - Sept/Dec-Mar
Harvest: Aug - Oct/Feb-Apr
Remember 5-4-4-3 (with first 4 having 2 sub phases)
Dormancy
When is dormancy and what condition triggers it
North: Nov - Mar
South: May - Sep
Triggered by avg air temps below 10°C
Dormancy
What happens in dormancy?
Leaves fall in autumn
Photosynth stops - vine sustains on energy (carbs in form of starches) stored in growing season in roots, trunk and branches
Dormancy
What are the main advserse conditions and impacts of dormancy?
Extreme cold
<-20°C - can damage or kill vine
<-25°C kills most vitis vinfera vines
Dormancy
What human activities occur?
Winter pruning
Budburst
What is budburst, when does budburst happen and what are vines’ main needs?
When compound buds from prior season burst open
North: Mar-Apr/South: Sep/Oct
Needs - avg air temp above 10°C
Budburst
What factors influence timing of budburst
- Air temp - over 10°C
- Soil temp- high temp=earlier budburst
- Grape var -
- Human factors - prior season pruning and vine growth
Budburst
What role do different climate classifications have on budburst - advantage in areas with larger seasonal temp differences?
Areas with clear differences in seasonal temps (continental) have advantage - more uniform budburst -> more uniformity in other phases and even in ripeness
- places with less difference - budburst less synchronized
Budburst
What can cause early budburst and what is the risk/implication?
Even a few days of warm temps in winter - early budburst can be damaged by frost –> lowers yields
Budburst
What role does soil temp play in budburst and where is it helpful?
Warmer soil = earlier budburst
Dry, free draining soils warm faster/retain warmth better than water-storing soils –>
* helpful in cool climates by starting growing season earlier
Budburst
What role does grape variety play in timing of budburst; examples of early/late budding varieties?
Different varieties need diff min average temps for budburst
Early: - burst at lower avg temps – PN, Chard, Mer, Grenache
Late: - need higher avg temps – SB, CS, Syr –> less risk of frost damage
Budburst
What human factors can influence timing of budburst?
Later winter pruning can postpone budburst - use in areas where frost is an issue
Budburst
Name 4 early budding varieties
Name 3 late budding varieites
Early:
* Chardonnay
* Pinot Noir
* Merlot
* Grenache
Late:
* Sauv Blanc
* Cab Sauv
* Syrah
What is transpiration and what is respiration?
Transpiration is process of drawing water and minerals from roots which is transported thru the vine to the leaves
Respiration is the process of leaves absorbing C02 and giving off oxygen and glucose (Photosynthesis)
Shoot and leaf growth
When is shoot and leaf growth, what is it and what are vines main needs?
When - mar - june (north); Sept- Dec (south)
What is it -shoots continue to grow; leaves and inflorescences mature; fastest growth bet budburst and flowering
* most of vine energy toward shoot growth until flowering
What vine needs - stored carbs, warmth, sunlight, nutrients and water
Shoot and leaf growth
What are adverse conditions and implications?
Low carb levels - from prior season
Water stress
Stunted shoot growth
Shoot and leaf growth
What does vigor mean and what are the implications?
What are the factors that influence vigor?
VIgor is vegetative growth of the vine - shoots, leaves, and lateral shoots
* implications - yield and ripening of grapes
* High vigor - long shoots with large leaves and lots of lateral shoots
Factors that influence:
* Natural resource avail - water,nutrients, temps
* Planting material - rootstock, variety, clone
* Human factors - canopy management choices
Shoot and leaf growth
What are vine needs and energy sources in this phase?
Carbs - stored in trunk and branches -> support initial shoot growth
Leaves - photosynth - need warmth and sun
Nutrients - Potassium, Nitrogen, phosphorus
Water
Shoot and leaf growth
What can cause low carb levels in vine and the implications?
What impact do low water levels have?
What is impact of stunted shoot growth?
Implications of adverse conditions
Low carb causes
Prior season - excessive yields, excessive pruning
This season - excess leaf removal, water stress, mildew infections
Low water impact:
* limited photosynth and shoot growth
* nutrient uptake inhibited by dry soil
Stunted shoot growth impact
* small, weak shoots -> dont flower properly, grape bunches dont fully ripen = poor quality and yields
Flowering and Fruit Set
When, what happens in this phase and what are vines main needs?
When - May-June (north); Nov-Dec (south)
Prompt buds burst and create lateral shoots for this years growth (new compound buds form for next yr)
Needs - warm temps min 17°C and sun/warmth/water/nutrients for bud fruitfulness
Flowering and Fruit Set
What is bud fruitfulness and what impacts it?
Fruitfulness = flowering potential of next yr compound bud
Things that impact following years harvest on # of flowers and yields
* shading of the compound bud
* temps that are consistnetly <25°C
* water stress
* nutrient deficiency
Flowering and Fruit Set
What are advserse conditions and implications for next yr crop?
Variety example that can handle bad conditions
Bad weather - rainy, cold, cloudy and windy
Impact on next year’s crop - bud fruitfulness of compound buds for next season -> big impact on yield
* number of inflorescences that will develop
* Riesling - cold tolerant - can form fruitful compound buds at low temps
Flowering and Fruit Set
What is flowering and what is fruit set?
Flowering - opening of flowers from inflorescences (pollination)
Fruit set - process of flowers turning into grape berries (fertilization)
Flowering and Fruit Set
What is the process of flowering and fruit set?
Stamen (anther and filamen) with pollen exposed ->
Pollination - pollen grains shed onto moistened stigma (self pollinating) ->
Germination - pollen granule creates pollen tube that penetrates the stigma and ovule within ovary ->
Fertilization - pollen tubes deliver sperm cells which fertilize the eggs
Flowering and Fruit Set
What is self-pollination?
○ Pollen transferred from stamens of one flower to stigma of same flower or different flower of same plant
○ Insects/wind do not play a role in grapevine pollination
Flowering and Fruit Set
When does flowering happen
Generally 8 weeks after budburst
Flowering and Fruit Set
What conditions are needed for successful flowering? What is main factor affecting flowering?
What are the implications of not having right conditions?
Very temperature dependent!! min 17°C
* warmer better -> flowering happens within a few days and more consistent
* cool temps - lengthens flowering process to weeks -> negative impact on evenness of grape ripening
Flowering and Fruit Set
What % flowers become grapes?
normally 30% of flowers become grapes, with a range of 0-60%
Flowering and Fruit Set
What conditions are needed for successful fruit set?
What are the impacts of adverse conditions?
Also very temp-related!
* Pollen germination needs warm temps 26-32°C
Cold, rainy, windy -> pollen tube growth inhibited -> irregular fruit set = poor yields in cool climates
Hot, dry conditions -> water stress = lower yields
Flowering and Fruit Set
What are 2 common forms of unsuccessful/irregular fruitset
Coulure - high proportion of flowers don’t turn into grapes
Millerandage - high proporation of grapes don’t have seeds
Flowering and Fruit Set
What is coulure and why?
Irregular fruit set which fails for high proportion of flowers
* ovule fertilization unsuccessful = no grape develops
Why
* carb level imbalance - results from low rate of photosynth dur to cool/cloudy or hot/dry conditions and also over vigor/too much shoot growth (use up carbs)
Some coulure is normal; excessive = major yield impact
Flowering and Fruit Set
What is millerandage and why?
which varieties prone to it?
High proportion of grapes are seedless
* still ripen normally, but are smaller -> reduce vol of wine that can be made and also impact quality
Why
* cold, wet, windy weather at fruitset
Varieties - chardonnay and merlot
Grape Development
When is it, what is it and what are vine’s needs?
When - June-Sept (north); Dec - Mar (south)
Growth and ripening of grapes
Needs - sun, warmth and mild water stress
Grape Development
What are the 4 phases of grape development?
- early growth
- veraison
- ripening
- late ripening
Grape Development
What are advserse conditions?
Too much water/nutrients -
Excessive shading of grapes -
Very cold or very hot thru day and night
Grape Development
What are the 7 key grape components (and definitions) during grape development?
- Water
- Sugar
- Acids - tartaric and malic
- Aroma componds - compounds that create aromas from ripening
- Aroma precursors - compounds that create aromas from fermentation; ex methoxypyrazines and terpenes
- Tannins
- Color compounds - anthocyanins
Grape Development
What are 2 key examples of aroma precursors and what var?
Methoxypyrazines - herbaceous/grassy - SB, CS, CF
Terpenes - floral/citrus - aromatic varieties
Grape Development
What is the vine transport system and when is it used?
Xylem - water transport tissue that moves H20 and some nutrients from roots through vine duriing early grape dev
Phloem - transport tissue that moves sugar from leaves to other parts of vine during ripening
Grape Development - Early Growth
What is status of key components during early growth?
Physical - shoots still growing; berries small, hard green
Water- rapid accum via xylem
Sugar - low
Acid - tartaric and malic accum
Aroma compounds - develop
Aroma precursors - methoxy begins to form
Tannin - very bitter, accumulate with sun
Color - NA
Grape Development - early growth
What is a specific ideal condition during this phase and why?
- Mild water stress - speeds process and makes smaller berries = less juice/lower yield BUT higher skin:pulp ratio = better quality -> more color, tannin, ACs
Grape Development - Early Growth
What are adverse conditions in this phase?
Too Much water/nitgrogen
* Prolongs this phase - too much vigor - vine puts energy into leaf/green growth vs developing berries = delays ripening and risks unripe grapes
Grape Development - Veraison
What is veraison and what is happening to key grape components?
What is another term for this phase?
Grapes change color
* black grapes go from green to red
Key components:
* overall growth pauses for a few days
* grape walls become more elastic
* Green chlorophyl in skin broken down
* Anothcyanin synthesis - complex color compounds break down to simpler ones - results in color change
aka - “lag phase”
Grape Development - Veraison
What is impact of sunlight before and after veraison?
Before - drives tannin accumulation
After - drives tannin polymerization
Grape Development - ripening
What is happening overall and what is general status of key components?
Physical - berry cells significantly grow with accum of sugar and water; shoot growth should have slowed significantly
Water - significant increase at beginning then xylem system slows
Sugar - significant increase at beginning of phase via phloem system
Acid - decrease
Aroma compounds - accum
Aroma precursors - accum
Tannin - accum
Color - accum
Grape Development - ripening
What happens to sugars, how are they formed and what are adverse conditions?
What are 2 ideal conditions for photosynth
(think sweet, sweet photosynth to relate sugar to phs)
Rapid accum at beginning, then slow
* Photosynth in leaves creates sugar solution which are transported by phloem system (as water flow drops)
* Key conditions for photosynth - temps bet 18-33°C and sunlight at levels above 1/3 full sunshine
Adverse conditions -
* cold/cloudy - low phs = low sugar levels in grapes
* hot dry/extreme water stress - vine slows/stops phs -> reduced sugar accum
Grape Development - ripening
What is grape transpiration and relationship between it and temp for sugar accum?
Why and what what risk of adverse conditions?
Grape transpiration - loss of water through grape skin which causes movement of sugars from leaves to grapes (phloem) driving sugar accum
Temp impact - warm/dry = faster sugar accum because sugar production and grape transpiration more rapid in high temps vs cool humid
Too warm - sugars accum too fast before flavors/aroma compounds and tannins can fully develop
Grape Development - ripening
What happens to acids and differences in types of acid?
What is impact in cool vs warm climates?
What are adverse conditions and impacts?
How does diurnal shift impact acidity?
Which acid drops more than the other and why?
THINK ABOUT RESPIRATION RATE
Acid concentration drops in this phase
* Tartaric - total amount stays same, but diluted by sugar and water
* Malic contentration drops more than tartaric - malic acid used in respiration during ripening phase; before the sugar is metabolised for growth
Cooler climates = higher acid: respiration faster in warmer climates, so cooler areas have higher natural acidity
Adverse conditions
* avg temps above 21°C+ in final month -> rapid loss of acidity (and higher pH)
* avg temps <15°C -> too much acid
Diurnal Shift
* In warmer areas that have higher diurnal shift - cooler night temps = less loss of malic acid due to slower respiration = retain more acidity than warm area otherwise would
Grape Development - ripening
Why do wines from cooler climates have higher natural acidity?
Respiration is process of releasing energy from the plant
Malic acid is metabolized during respiration ->
Respiration lower in cooler climates, so malic acid not depleted as quickly leaving higher acidity
Grape Development - ripening
What happens to aroma compounds and precursors during ripening?
What are adverse condition impacts?
What is relationship between climate ripening conditions and aroma compounds?
Methoxypyrazine levels fall - if cool/limited sun or bunches shaded -> overly herbaceous notes
Terpenes and other aroma compounds/precursors increase
Warmer temps = riper aromas vs cooler climates
Grape Development - ripening
What happens to tannins (black grapes) during ripening?
Tannin levels high at veraison and decrease slightly during ripening (white grapes = low tannin levels)
Grape Development - ripening
What is tannin polymerization?
How does sun related to tannin ripening?
Tannin polymerization - small tannin molecules combine to form large chains = less bitter
Sun before veraison -> drives tannin accumulation
Sun after veraison -> drives tannin polymerization
Grape Development - ripening
What happens to color compounds during ripening?
What are optimal conditions?
Anthocyanins increase during ripening
Optimal = plenty of sun and temps 15-25°C
Grape Development - ripening
What factors influence length of ripening phase and how?
Grape variety - some var ripen earlier than others - Chard, PN; CS Grenache late, zin uneven
Climate conditions - sugar ripening fastest in warm/dry
* too hot/dry - phs slows/shuts down = fewer grapes made, less sugar, less ripe
Vineyard management - high yields, excessive shading w/in canopy that are still growing slows ripening
Time of harvest - depends on both natural and human factors
Grape Development - extra ripening
What happens in this stage, why?
What conditions needed?
Variety examples
Grapes left on vine start to shrivel -> sugars concentrate and extra ripe aromas dev
* no more sugar or water go into grape, but water is lost thru grape transpiration = concentrated sugars
Conditions - best is hot/dry/sunny climate
Ability to leave grapes on vine depend on weather and disease pressures
Syrah susceptible
Grape Development
What are main considerations for determining appropriate ripeness and implications?
○ Sugar level - directly linked to alc levels in dry wines and sweetness and alc level in sweet wines
○ Acid level - depends on wine style; higher acid needed in sw and sweet wines
○ Aroma/flavor profile - depends on wm preference - as grapes ripen, flav/aroma change from underripe/herbaceous to fresh to riper fruit to jammy/cooked
○ Tannin ripeness - very complex; tannin compounds interact with other compounds and change perception of tannins:
* A little RS - make tannins feel softer
* High acid/bone dry - tannins feel more astringent
Grape Development
What are implications of growing environment on ripeness?
How do winemakers address them?
Adjustments
○ Warm climates - tend to have higher alc levels –> since preferred sugar/acid levels may not be reached before desired tannin/aroma ripeness
○ Adjustments to preferred balance can be made in winery
○ Easier to adjust sugar/alc/acid –> WMs often aim for tannin and aroma ripeness and adjust other aspects
