GRAPEVINE PHENOLOGY Flashcards
What is phyllotaxy?
Arrangement of leaves in space or pattern of lateral organs on the shoots
Describe from the following vitis species if they are male/female/hermaphroditic
1. Vitis Riparia
2. Vitis Romanetii
3. Vitis Vinifera
- Male
- Female
- Hermaphroditic
How much % of the flowers are successfully fertilised in general?
30%
Which parts of the vine store nutrients?
All woody parts (lignified)
What are ‘ephemeral’ roots?
The roots that are the main structure of the vine. They are lignified (woody)
What grows first, the bunch or the tendril?
Tendril. Is needed for support.
At what part of the shoot will next years bud be formed?
At the place that has this years leaf
Which parts of the vine grow mostly at night? And which in the morning?
Night: Berries and tendrils
Morning: leaves
Name three types of buds
- Primary
- Lateral
- Dormant
What is meant by ‘apical dominance’?
The buds the furthest away will push the first. Vine wants to grow
Which part of the vine has the most nitrogen?
Leaves, in the chloroplast
What kind of acid is in high amounts in a dormant vine?
Abscisic acid. To keep metabolism to a minimum necessary for survival
What happens when the vine wakes up after dormancy? (4)
- Remobilization of nutrient reserves by pumping sugar into the xylem
- High hydrostatic pressure in entire xylem
- Rehydratation and reactivation of dormant buds
- Delivery of sugars in the absence of phloem flow (enable the buds to resume growth and break)
What forms a bud? (which part)
Shoot apical meristem
Which nodes in the bud will mostly form bunches?
Nr. 4 or 5.
Nr 1-2/3 only have leaves
At what part of the shoot are the buds the most fertile? start/middle/end
End
Fruitfulness of dormant buds increases from the shoot base to the middle and then decreases again
What are crown or basal buds?
Buds at the base of the shoot or cane. Can be a lateral, primary or secondary bud.
What is meant by secondary wood growth?
‘Shoot maturation’. The moment that shoots begin to lignify and become canes (after fruitset-mid summer)
What happens simultaneously with the secondary wood growth?
Restore of reserves (starch, proteins and amino acids)
What is the function of the Xylem?
Responsible for delivering water and nutrients from the roots to the canopy
What is ‘tylose’ in a vine?
Tyloses are balloon-like swellings or projections that fill the vessels. When a tylosis is full formed it plugs the vessel. The vessel can no longer conduct water. Created in stressful conditions like drought.
What is meant by the ‘plasticity’ of the plant?
The ability to adapt to environmental changes
What is meant by the ‘regime shift’ in the eighties?
The effects on global warming due to industrialising of the world
What is the function of the leaf stomata? How does it behave in different conditions?
Transpiration.
- In hot conditions with the access to water the stomata will open and transpire, thus cooling down the canopy.
- In hot conditions without access to water the stomata will close to prevent water loss. Canopy heats up and photosynthesis wil be low
Why can’t berries not control their temperature? What do they need?
Because they cannot transpire
They need shade
What is the impact of high temperatures (37+C) on berries?
Lower acidity
Lower color (anthocyanin will be broken down)
What are ‘anlagen’?
Undifferentiated primordial which may develop in a flower cluster or tendril
What determines if an undifferentiated primordial will develop into a flower cluster or a tendril?
During growing season previous season: temperature (around 20C) and full sunlight will give a flower cluster. Otherwise it will be a tenril
Which cluster will be the highest quality? The one close to the arm or to the end of the arm?
The one closest to the arm
What is a ‘bract’?
The cap around the inflorescence in the newly formed bud
How many months is the reproductive cycle of a vine? From newly formed bud to harvest?
15-18 months, starting in November of the previous harvest
Which buds are more fertile? The basal buds or the apical buds? Why?
The apical buds. Because environmental conditions are then more advantageous than during flowering
What is a reason to do bud dissection?
By comparing this years and last years numbers of cluster primordial (per cluster), you can decide the number of nodes left during pruning.
When is the best time to do bud dissection?
After veraison. But the best is after harvest and before pruning.
What is an ‘apical bud’? More or les fertile?
A new bud at the tip of the shoot. More fertile because due to time in the season there weas higher temperature and light.
What is the most important time of the year (in terms of reproductive cycle?
Flowering. Because it is flowering for the current year, but also the moment that weather conditions are determining the cluster/tendrils for next year
Do you leave more or less buds on a high vigor vine?
More. Prune to capacity!
How much % of the flowers will in an average year turn into bunches?
Around 30%
Why can rain be a problem during flowering?
Because rain (without drying in-between) will cause the caps to stick to the flowers. Pollination will be more difficult
A high vigor implies … ?
Delayed bud burst, flowering, veraison and maturity.
What are results of increased vigor? (4)
Growth and high number of buds (more leaves)
Higher flower initiation
Higher berry diameter
Increase risk of coulure
