Vine Anatomy Flashcards
Which species of grape is most commonly used for winemaking?
Vitis Vinifera
Where did this V. vinifera originate?
Eurasia
What are the four most common North American grape species?
- Vitis Riparia
- Vitis Labrusca
- Vitis Berlandieri
- Vitis Rupestris
What are North American grape species mostly used for?
Rootstocks onto which Vitis vinifera is grafted
What are the four main sections of a vine?
- Main shoots
- one-year-old wood
- permantent wood
- roots
Of what does the canopy consist?
The main shoots and all of their major structures - stem, buds, leaves, lateral shoots, tendrils and inflorescences/grape bunches.
What is the function of the main axis of the shoot?
- Transports water and solutes (sugars and minerals) to and from the different structures
- A store of carbohydrates
What are nodes and internodes?
Nodes: The little swellings along the stem, where the other structures are attached.
Internodes: The lengths of stem in between the nodes.
What are canes?
Green shoots that turned brown and lignified in late summer after the leaves have fallen
What are buds and where do they form?
Buds form between the leaf stalk (petiole) and the stem. As they mature they contain all the structures in miniature that will become green parts of the vine, including the stem, buds, tendrils, leaves and often inflorescences.
What are the two types of buds?
- Compound buds
- Prompt buds
What are Compound buds?
- AKA Latent buds
- They form in one growing season and break open in the next growing season (provided they are retained during winter pruning).
- They produce the main shoots in the next growing season.
- Within a compound bud, there is typically a primary bud (the main growing point) and smaller secondary and tertiary buds. The secondary and tertiary buds usually only grow if damage has occurred to the primary bud (e.g. spring frost).
What are Prompt buds?
Prompt buds form and break open in the same growing season. They form on the main shoot (that has just grown from a compound bud) and produce lateral shoots.
What is a lateral shoot?
- They grow from buds formed in the current year (prompt buds).
- Smaller and thinner than the main shoot
- Their main function is to allow the plant to carry on growing if the tip of the main shoot has been damaged or eaten.
- Can provide an additional source of leaves for photosynthesis
Why is a lateral shoot growing near the base of the main shoot undesirable?
- They impede air flow
- They may shade the fruit too much.
What is a second crop on lateral shoots?
- Lateral shoots often produce inflorescences.
- These inflorescences become bunches of grapes later than those on the main stem and hence ripen later.
What are the problems with a secondary crop from lateral shoots?
The fruit:
* Is higher in acidity
* Is lower in potential alcohol
* May have unripe tannins and aromas/flavours
* In black grapes may have less colour
What’s the benefit of hand harvesting when it comes to the second crop?
You can be selective and pick the second crop later instead of mixing.
What is the function of the vine tendrils?
Tendrils support the vine and they curl around trellis wires and keep the canopy in place.
What is the function of a vine’s leaves?
Leaves are the site of photo synthesis. They are also the site of stomata.
What is the purpose of stomata?
- Pores on the underside of the leaves
- Let water diffuse out (Transpiration)
- Let CO2 in
- Close if the vine is water stressed
What is an inflorescence?
- The inflorescence is a cluster of flowers on a stem, which becomes a bunch of grapes at fruit set.
- The number of inflorescences on each main shoot can depend on the grape variety, but is usually between one and three.
What are the three parts of a grape?
- the skin
- the pulp
- the seeds
What does grape pulp contain?
It contains water, sugars, acids and some aroma compounds and aroma precursors.
What colour is most pulp? What is the exception?
- The pulp of most grapes is colourless.
- Exceptions: teinturier varieties, which have red-coloured pulp (e.g. Alicante Bouschet) not common.
What do the skins contain?
The skin of the grape contains a high concentration of aroma compounds and aroma precursors, tannins and colour compounds.
What do the seeds contain? What colour are the seeds?
- Seeds contain oils, tannins and the embryo, which can grow into a new plant.
- Seeds mature inside the grape, turning yellow to dark brown.
What is the bloom?
A powdery waxy coating that covers the surface of the grape.
What is One-Year-Old Wood?
- One-year-old wood refers to the main shoots from the last growing season that were kept at pruning.
- It supports the compound buds that will break to release the main shoots for the upcoming growing season.
What is permanent wood?
- These are the woody parts of the vine that are older than one year, including the trunk.
- The trunk and cordons provide support for the other parts of the vine.
- They transport water and solutes to and from different parts of the vine and store carbohydrates and nutrients.
