1.1 - Vine Needs & Growing Environment Flashcards
List the four sections of the vine
Primary Shoots, One-Year-Wood, Permanent Wood, Roots
List the parts of the Canopy
Stem (Xylem & Phloem), Buds (Compound & Prompt), Lateral Shoots, Tendrils, Leaves, Inflorescences, Berries
List parts of the grapes
Stem, seeds, pulp, skin, bloom
Where do the Prompt Buds form?
They form ON the primary shoot (that has grown from the Compound Bud) and produce lateral shoots.
How are lateral shoots different from primary shoots?
They grow from Prompt Buds, are smaller and thinner than primary shoots, primary function is to allow the plant to carry on growing if the tip of the primary shoot is damaged or eaten
Advantages & Disadvantages of Lateral Shoots
Pros: additional leaves for photosynthesis if near end and can benefit from photosynthesis; second crop could help balance the original crop (i.e., will ripen later). / Cons: if near 1-yr-wood or perm wood, impedes airflow and shades the fruit; redirects energy to canopy; second crop
Advantages & Disadvantages of Second Crop
Pros: Help balance the original crop if done carefully; Cons: bunch of grapes later than rest of crop, which means ripens later - higher in acidity, lower in sugar, and unripe tannins and aromas/flavors, and color
Describe how photosynthesis works
Stomata open on the underside of the leaves, letting water difuse out and CO2 for photosynthesis enter. Chlorophyll takes the CO2 and water inhaled by stomata and converts them into sugars, carbs, and oxygen. Once the vine has created its food via photosynthesis, it is transported through the phloem using the source to sink where sugars and carbs can be used to create energy or be stored in the woody structures and roots or grapes.
Describe transpiration
As water diffuses from the leaf, transpiration draws water and nutrients from the soil up through the vine to the leaves. Stomata partially close if the vine is water stressed to help converse water, but this limits photosynthesis by prevent CO2 from entering the vine
List items in grape pulp
Majority of the grape’s weight and volume; contains water, sugars, acids and some aroma compounds and aroma precursors
What are the main functions of the permanent wood?
Provide support to the other parts of the vine. Transport water and solutes to and from different parts of the vine (transpiration), and store cabs and nutrients
What are the primary functions of the roots?
Anchor the vine. / Uptake of water and nutrients. / Store carbs. / Produce hormones that assist with vine growth and grape ripening.
What is the grape grower’s aim?
To produce the largest possible crop of grapes that are suitable ripeness and quality for the style being produced.
Identify factors for determining ripeness
Level of sugar / acidity / profile of aromas/flavors; tannin ripeness,
How does temp impact ripeness?
Sugar - directly linked to alcohol; more quickly in warm, dry climates (thought too hot can slow it down) whereas in cooler or cloudy climates, can struggle to ripen. / Acidity: warm, dry climates, falls more rapidly whereas in cooler climate or with a high diurnal range, it is retained; Aromas/Flavors: warm or cooler climate not as clear cut and not necessarily linked; Tannin Ripeness: warm or cooler climate not as clear cut and not necessarily linked / Warm Climates: sugar and acid levels may be reached before aroma and tannin ripeness
Define Optimal Ripeness
Time at which the combo of sugar, acid, tannin, and aroma ripeness is at its most favorable; depends on wine style, grape variety, and preferences of winemaker with ultimate aim for balanced wine.
List a vine’s needs
Water, sunlight and warmth for photosynthesis (CO2 out of grower’s control); warmth also needed; and certain nutrients
Adverse Conditions to Dormancy
Extremely cold: <-20ºC (-4ºF) can severely damage or kill; <-25ºC (-13ºF) will kill most vinifera
Unusually mild conditions - frost and shortened life
Dormancy: Protect against Extreme Cold
Site Selection (hillsides can be 5ºC (9ºF) warmer than valley; near large or deep bodies of water / Choice of grape varieties / Hilling Up
Dormancy: Protect against unusually mild conditions
A few mild days can cause early budburst that can then be killed with subsequent frost, leading to lower yields / No dormancy, then hasn’t rested and decreased lifespan.
Budburst
Avg air and soil temp >10ºC (50ºF) (early or late budding) / Buds swell and open and green shorts start to emerge
Budburst Adverse Conditions
Frost - winter pruning late in dormancy can postpone budburst if spring frost known issue / Cold Soils (dry, free draining soils warm up more quickly than water-storing soils, such as clay
What impacts vigor?
Natural resources (temp, water, nutrients); planting material (grape, clone, and rootstock); and presence of any disease (virus can lower vigor)
Vine’s Needs During Budburst
Stored carbs / Warmth, sunlight, nutrients (nitrogen, potassium, phosphorus) and water (water stress limit photosynthesis and shoot growth and uptake of nutrients from very dry soil)
Budburst Adverse Conditions
Low carb levels (excessive leaf removal, water stress, mildew infections or excessively high yields previous growing season) / Water stress
Vine’s Needs for Flowering & Fruit Set
Min 17ºC (63ºF) - low temps lengthen flowering duration, which decreases evenness of grape ripening
Conditions limiting bud fruitfulness
Conditions from prior growing season / shading of compound buds; temps <25ºC (77ºF); water stress; nutrient deficiency
Define bud fruitfulness
Number of inflorescenses that will develop from a bud
Describe pollination
Pollen-laden stamens (anther and filament) are exposed; pollen grans are shed and land on the moistened stigma surface / grains germinate with each pollen grain producing a pollen tube (26-32ºC (79-90ºF) / pollen tubs penetrate the stigma and the ovule in ovary and deliver the sperm cells that fertilize the eggs in the ovule, leading to the formation of a grape berry; fertilized ovules form seeds (up to 4 per grape); and wall of the ovary enlarges to form the skin and pulp
What is key cause of poor yields in cool climates?
Pollen tube growth is negatively affected by cold, rainy, and/or windy conditions, resulting in irregular fruit set
What can cause coulure?
Imbalance in carb levels, resulting from low rates of photosynthesis, which may be caused by cold, cloudy conditions or hot, arid conditions with high water stress; vigorous shoot growth which diverted carbs away from inflorescence and that could be result of very fertile soils, heavy application of fertilizers, and vigorous rootstocks; and some varieties are more susceptible
Negative Impact of Millerandage
Seedless grapes smaller, so reduces volume of wine; some stay small, green and unripe, which impacts quality
Results from cold, wet, windy weather at fruit set; some varieties more susceptible
Vine Needs - Flowering & Fruit Set
Warm temps (min 17ºC/63ºF) / sunlight, warmth, water and nutrients for bud fruitfulness in next growing season
Adverse Conditions - Flowering & Fruit Set
Rainy, cloudy, windy, cold temps
List the stages of grape development
1 - early grape growth / 2 - veraison / 3 - ripening / 4 - Extra-ripening
What occurs during early grape growth?
Hard green grapes start to grow in size; tartaric and malic acids accumulate; some aroma compounds and aroma precursors; tannins accumulate and are very bitter, sugars are low; shoot growth continues but more slowly
What occurs during veraison?
Grape cell walls becomes more stretcy and supple; green-colored chlorophyll in skin cells is broken down and black grapes start to become red due to synthesis of anthocyanins
What occurs during ripening?
Cells in the grape expand rapidly; sugar and water accumulate; acid levels fall; tannins, color and number of aroma precursors and aroma compounds develop; water flow via xylem slows down and solute transported to grape by phloem
Needs for Photosynthesis
Max temp rate between 18-33ºC (64-91ºF) / sunlight levels that are above one third full sunshine
What happens to acid during flowering & fruit set?
Tartaric Acid - total amount doesn’t change, but its concentration fall during ripening because it’s diluted by the sugar and water / Malic Acid - concentration falls more than tartaric acid because malic acid can be metabolized, rarther than sugar, in respiration during ripening / Mean temps >21ºC (70ºF) in the final moth of ripening can lead to rapid loss of acidity, whereasmean temps <15ºC (59ºF) can reduce acid loss to point acidity levels in the must are too high
What happens with respiration in cooler climates?
Respiration is slower at cool temps, which is why wines from cooler climates tend to have higher natural acidity
What happens with respiration in warmer climates?
Cool nighttime temps mean that less malic acid is lost during respiration. Warm areas with high diurnal range (Central Otago, WA) can produce wines with higher acidity than those with warmer nighttime temps
Describe what happens to tannins through ripening
Levels of tannins are high at veraison and decreases slightly throughout ripening
Anthocyanins increase during the ripening stage and increase most rapidly with plentiful sunlight and temps between 15-25ºC (59-77ºF)
Methoxypyrazine levels fall, but cool temps and limited sunlight can hinder this decrease and resulting wines may show particularly herbaceous aromas/flavors
Terpenes increase during the ripening stage
Link between ripening conditions and aroma compounds is difficult but generally warmer, sunnier climates tend to produce grapes and wines with aromas that could be described as ‘riper’ than cooler, less sunny climates
Define ‘polymerise’
Process in which relatively small molecules combine chemically to produce a very large chainlike or network molecule
Tannins polymerize from veraison through ripening, causing them to become less bitter; sunshine on grapes promotes tannin accumulation pre-veraison and greater polymerization post-veraison
Describe the relationship between grape transpiration and sugar accumulation
Water flow via the xylem slows down and a sugar solution (mixture of mainly sugar and water) is transported to the grape by phloem
Movement of the sugary solution from the phloem into the grape is correlated to the rate of grape transpiration
Grape transpiration, and therefore sugar accumulation, is faster in warm, dry conditions than cool, humid conditions; but, in warm conditions, this assimilation of sugar can be too rapid and reach high levels before aromas/flavors and tannins have developed fully
Identify the factors upon which the four stages of grape growth depend
Grape Variety (early ripening variety needs less heat and late ripening needs a greater amount of heat)
Climatic Conditions (sugar ripening is quickest in warm, dry conditions but very hot or dry conditions can cause vine to shut down)
Management of the vine and vineyard (high yields, excessive shading within the canopy, shoots still actively growing can all slow down ripening)
Time of harvest depends on human factors (desired wine style, logistics), natural factors (rain, onset of disease), etc.
Identify a vine’s needs for ripening
Sunlight
Warmth
Mild water stress
Describe how mild water stress impacts grape ripening
Water flow into the grape is high and is mainly transported to the grape by xylem
Speeds up at ripening and leads 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 (higher levels of color, tannins, and aroma compounds)
irrigation can be used to monitor and manage water levels
Identify the conditions that would adversely impact grape ripening
too much water and nutrients - encourage shoot growth in preference to grape ripening, causing a delay in the onset of ripening which could mean not sufficient time for ripening before weather becomes cooler and grapes need to be harvested
Excessive shading of grapes (or cloud cover) can hinder decrease of methoxypyrazine levels and resulting wines may show particularly herbaceous aromas/flavors
Very cold or very hot conditions throughout the day and night - if cold weather or constant clouds, then rate of photosynthesis is hindered which may hinger sugar levels in grapes; and if very hot, dry conditions, then extreme water stress can cause photosynthesis to slow or stop and thereby hinder sugar accumulation
Identify what occurs during extra-ripening
If left on vine, grapes start to shrivel, especially in hot, sunny, dry climates
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 and extra-ripe aromas can develop
Desirable in some wines, but not always possible to leave grapes on the vine if the weather conditions and/or disease pressure exists
Syrah susceptible to this
