CH 2 : Vine Growth Cycle

Question 1

What is the vines annual lifecycle?

Answer 1

Dormancy
Budburst
Leaf + Shoot growth
Flowering and fruitset
veraison
ripening
harvest

Question 1

what temperatures prompt budburst

Answer 1

10C +

Question 2

what are the main threats at budburst?

Answer 2

inconsistent temperatures (uneven development/harvest)
frost (yield)
cold soils (delay)

Question 3

Will a Maritime climate have a more or less even budburst?

Answer 3

less even due to less dramatic shift between seasonal temperatures which may cause some delayed budding and an unhomogenous grape/vine development throughout the season

Question 4

What soil type would be ideal to encourage budburst in a cool region?

Answer 4

free draining, dark coloured soils

• don’t retain cooling water
• dark soils retain solar heat

Question 5

How would a vigneron mitigate frost risks at budburst?

Answer 5

• late winter pruning to postpone budburst
• aspersion sprinklers
• heaters
• wind machines

Question 6

what are the main threats during shoot and leaf growth?

Answer 6

water stress
low carbohydrate levels (from prev. growing season)

Question 7

What are the key micronutrients the vine requires?

Answer 7

nitrogen, potassium, phosphoruswha

Question 8

what are the minimum temperatures required at flowering and fruitset?

Answer 8

17C for flowering
26-32C for fruitset

Question 9

what will limit bud fruitfulness at fruitset and flowering?

Answer 9

Excess shade
low temperatures
extreme rain/wind
water stress

Question 10

what conditions can affect the vine at flowering/fruitset?

Answer 10

millerandange - high proportion of seedless grapes. caused by cold, wet, windy weather at fruitset

couleur - failed fruitset for a high proportion of flowers. Caused by imbalance in carbohydrate levels from low rate of photosynthesis (eg. clouds, fogs etc.)

Question 11

what is the role of the xylem and phloem?

Answer 11

xylem transports water up to the plant
phloem transports sugars and proteins

Question 12

what are the main threats during grape development?

Answer 12

• excess water and nutrients
• too much shade
• very hot/cold conditions throughout day and night

Question 13

what effect does the combined excess of nitrogen and water have on a vine during grape growth?

Answer 13

It can prolong the growth season as these direct nutrients towards the canopy rather than the grape.
This may delay ripening and harvest further in the season

Question 14

How does water stress affect the plant during grape development

Answer 14

It hastens the season as the vine directs its resources towards the reproductive (grape) system.
It may also lead to smaller grapes with a higher juice:skin ratio which may be desirable.

Question 15

What is the effect of sunlight during grape development?

Answer 15

• anthrocyanin development
• tannin precursors (esp. at veraison)
• tannin polymerisation (post-veraison)
• sugar accumulation through higher photosythesis rate
• methoxypyrazines breakdown
• malic acid dips late in season as sunlight increases respiration rate

Question 16

How sugars get transported into the grape

Answer 16

via the phloem

Question 17

How can a warm climate negatively influence ripening?

Answer 17

sugars may accumulate before phenolic ripeness is achieved

Question 18

At what temperature does malic acid begin to rapidly drop?

Answer 18

21C

Question 19

Beneath what temperature in the ripening season will the acid loss halt

Answer 19

15C

Question 20

between what temperature do anthrocyanin optimally develop?

Answer 20

15-25C