Misc Flashcards
Draw the vine lifecycle
Name a vine species tolerance of extreme cold
Vitis amurensis (Russian/Chinese in origin)
Name a wine region where it is never cold enough for dormancy
Canary Islands
What are the two phases within dormancy
Endodormancy, Ecodormancy
What triggers endodormancy?
Endodormancy is triggered by shorter days (photoperiod signal) and cooler temperatures at the end of the growing season.
What happens during endodormancy?
So that cell content won’t form damaging ice crystals (and freeze) in cold temperatures, a plant growth regular (Ascorbic Acid) triggers decreases the level of water in various tissues with the process of dehydration through movement of water to intercellular spaces, and accumulation of sugars and protein complexes that bind water and serve as cryoprotectants.
The grapevine will not grow even under the favorable (growing) environmental conditions, such as adequate moisture, long day length, and warm temperatures.
What make a grapevine transit from endodormancy to ecodormancy
A minimum number of chilling hours (varies by variety but in range 150-200 hours). A chilling hour is a one spend ABOVE 0C.
What is ecodormancy
The second phase of dormancy is called ecodormancy, a phase in which environmental conditions don’t allow the vine to bud break. In this phase, the plant is actually ready to grow, but low temperatures inhibited bud development, therefore in this stage, low-temperature blocks the bud development.
What happened in 1956
Big freeze in SW France. Killed off most Malbec which, with the exception of Cahors, was not replanted.
Name a grape variety that buds below 10C and one that buds above
Merlot (under), Ugni Blanc (Above)
Draw the parts of a flower
What limits bud fruitfulness (the number of inflorenscences that will develop)
Shading of compound bud, temperatures low (under 25C), water stress, and nutrient deficiency
How many seeds in a grape
Up to four
Typical time between busburst and flowering
Around 8 weeks
Optimal conditions for pollen germination
Temparatures from 26C-23C.
Creates creates sub-optimal conditions for germination
Low temperatures, rain and wind slow down pollen tube growth and can result in irregular fruit set. Hot dry, conditions lead of water stress and can also have a nagative effect.
Which grapes more naturally prone to coulure
Grenache, Cabernet Sauvignon, Merlot, Malbec
Which grapes more prone to millerandage?
Chardonnay, Merlot
Above what mean temperature in last month of grape ripening can lead to too little acid?
21C
Below what mean temperature in last month of grape ripening can lead to too much acid?
15C
What transports water to the grape
Xylem
What transports sugar solution to the grape
Phloem
