3. The Growing Environment Flashcards
What constitutes the growing environment?
- temperature and sunlight,
- water,
- nutrients,
- climate,
- weather,
- climate change.
What is vineyard management aimed at?
At making best use of the natural resources available.
What will have a a DEFINING influence on the wine produced: the growing environment or the winemaker’s operations with the must/wine?
the growing environment and its effect on natural resources.
What’s the optimal temperature for the dormancy of the vine?
under 10°C, extreme temperatures (around -20°C) can cause winter freeze and damage the vine.
What’s the optimal temperature for budburst?
above 10°C,
+ a significant rise in temperature.
What’s the optimum temperature range for shoot and leaves growth and photosynthesis?
18–33°C
What’s the optimum temperature for flowering? fruit set?
above 17°C.
What’s the optimum temperature for fruit set?
26–32°C.
What’s the optimum temperature to promote increased bud fruitfulness?
above 25°C.
How does warmth influence grape ripening?
- faster sugar accumulation (due to optimum photosynthesis, increased grape transpiration)
- malic acid decrease
- a rapid loss of acidity (mean t above 21°C in the final month of ripening)
- riper aroma/flavours
Define photosynthesis.
is a biochemical reaction where leaf combines CO2 + water to produce glucose + oxygen.
Define transpiration.
Transpiration is a biological process when water travels from the roots to small pores underside the leaves - stomata. The leaf pores stomata diffuse water OUT and let CO2 for photosynthesis IN. The released water transforms into vapor (испарение) and it evaporates into the atmosphere.
How does cool temperatures influence grape ripening?
- reduce acid loss (mean t below 15°C in the final month of ripening) => acidity levels in the must are too high,
- hinder the breakdown of methoxypyrazines (herbaceous aromas),
- slow down anthocyanin synthesis (development of colour in black grapes),
- most likely slow down tannin synthesis.
What is the optimum t range for anthocyanin synthesis (colour)?
15–25°C
How can extreme heat and conditions affect grape ripening?
- slow or stop photosynthesis
Why can photosynthesis slow/stop during heat?
- due to the heat sensitivity of enzymes (that catalyse photosynthesis),
- water stress => shutting of stomata to prevent water loss => the closed stomata limit intake of CO2 (which is needed for photosynthesis).
What’s the amount of sunshine optimal for photosynthesis?
NOT full sunshine,
below 1/3 of full sunshine.
What are the effects of grape exposure to sunshine?
- enhancing of anthocyanins (colour pigments),
- the reduction of methoxypyrazines (herbaceous aromas/flavours),
- accumulation of tannins (pre-véraison),
- promotes tannins polymerisation (after véraison) => less bitterness,
- increased levels of favourable aroma precursors and compounds (terpenes for fruity and floral aromas),
- lower acidity levels (malic acid is used up intensively in grape RESPIRATION when grapes are warmed up),
- successful fruit set (sunshine in late spring / early summer),
- promotes bud fruitfulness in next year’s growing season (due to exposure of compound buds),
- ’–’ sunburn on sun-exposed grapes.
How is latitude correlated with solar radiation QUANTITY?
Regions at LOWER latitudes (nearer the Equator, e.g. Mendoza, South Africa, New South Wales) will receive MORE solar radiation per annum than regions at higher latitudes (nearer the Poles, e.g. northern France and Germany).
How is latitude correlated with solar radiation INTENSITY?
Regions nearer the Equator (at lower latitudes) receive more intense solar radiation than those nearer the poles (at higher latitudes).
Why solar radiation is less intense nearer the poles (at higher latitudes)?
- solar radiation must travel through a larger section of atmosphere to reach the Earth’s surface,
- solar radiation is more diffuse (the radiation hits the Earth at a low angle, so the radiation is spread over a larger area).
What are characteristics of grapes grown at lower latitudes compared to those at higher latitudes?
higher levels of sugar,
lower levels of acidity,
riper aromas,
higher but riper tannins and more colour intensity (in black grapes).
How is latitude correlated with The number of hours of solar radiation?
Low latitude regions => similar daylight hours throughout all seasons.
High latitude regions => longer daylight hours in the summer and shorter daylight hours in the winter => a longer duration of time over which photosynthesis can take place in the growing season => helping the vine to produce enough sugar even in cooler temperatures.
What latitudes are suitable for growing wine production grapes?
Bw 30° and 50° latitude on each side of the Equator.
