D1C01 The Vine Flashcards
1.1.1 Describe the anatomy of the vine. 1.1.2 Explain how the components of the grape develop through the ripening process.
What is Vitis Vinifera?
V. Vinifera is a vine species, to which belong the majority of known grape varieties. It’s indigenous to Eurasia.
Name 4 North American vine species?
- V. Labrusca
- V. Riparia (Coast vine)
- V. Berlandieri (Lime vine)
- V. Rupestris (Rock vine)
What is the function of North American vine species?
Rootstocks onto which V. vinifera is grafted.
Also used in wine production in some regions (e.g. New York State).
Describe the 4 sections of the vine’s structure
- main shoots
- one-year-old wood
- permanent wood
- the roots
Define the canopy
The main shoots and all of their major structures – stem, buds, leaves, lateral shoots, tendrils and inflorescences/grape bunches are collectively called the canopy.
Describe the major structures of main shoots
- stem
- buds
- leaves
- lateral shoots
- tendrils
- inflorescences/grape bunches.
What is the function of the stem?
The stem is essentially the structure to which all the other structures are attached.
It transports water and solutes to and from the different structures.
The stem is also a store of carbohydrates.
What are canes?
In late summer, the leaves fall from the vine and the green shoots lignify (become woody and rigid) and turn brown; from this point they are called canes.
Where do buds form and what do they become?
Form between leaf stalk (petiole) and stem – with maturation, become green parts of vine
What structures do buds contain as they mature?
Buds 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 main types of buds?
- Compound buds (also called latent buds)
- Prompt buds
When are compound buds formed and break open?
Compound buds (also called latent buds) form in one growing season and break open in the next growing season (provided they are retained during winter pruning).
What is the function of compound buds?
Compound buds produce the main shoots in the next growing season.
What is the structure of compound buds?
Compound buds have a primary bud (the main growing point) and smaller secondary and tertiary buds.
What is the function of secondary and tertiary buds?
The secondary and tertiary buds serve as additional growing points. They usually only grow if damage has occurred to the primary bud (e.g. spring frost).
When are prompt buds formed and break open?
Prompt buds form and break open in the same growing season.
Where are prompt buds formed and what do they form?
They form on the main shoot (that has just grown from a compound bud) and produce lateral shoots.
What are lateral shoots?
Grow from prompt buds.
Lateral shoots are smaller and thinner than the main shoots. Lateral shoots have a stem, leaves, buds, tendrils and sometimes inflorescences.
Where do lateral shoots grow from?
Lateral shoots grow from buds formed in the current year (prompt buds).
What is the function of lateral shoots?
Their main function is to allow the plant to carry on growing if the tip of the main shoot has been damaged or eaten.
Lateral shoots can provide an additional source of leaves for photosynthesis, which can be useful if the laterals are near the ends of the main shoots and able to benefit from sunlight.
What is photosynthesis?
The process by which green plants use sunlight to produce sugars from carbon dioxide and water:
CO2 + 2 H2O + photons → CH2O + O2 + H2O
(CH2O being carbohydrates, e.g. sugar)
Explain why growth of laterals nearer the base of the main shoot is undesirable?
As laterals impede air flow and can shade the fruit too much. They may be removed in summer pruning
Define ‘second crop’.
Lateral shoots often produce inflorescences, which can be known as a ‘second crop’. These inflorescences become bunches of grapes later than those on the main stem and hence ripen later.
Explain the difference between the bunches of the main crop and the second crop, if harvested at the same time.
If harvested at the same time as the main crop, the bunches in the second crop will be higher in acidity, lower in potential alcohol and may have unripe tannins and aromas/flavours and, in black grapes, less colour development.
What is green harvesting and explain why it may be desirable?
Green harvesting is the removal of the second crop during the growing season.
This technique is thought to enhance the ripening process and improve the uniformity of ripeness of the remaining bunches.
Would you advise green harvesting when hand harvesting?
If fruit is hand-harvested, the ability to be selective means the second crop need not be picked or can be separated.
Explain the effects of the second crop when machine harvesting?
A vine grower can not avoid picking up green crop, and therefore it may have an impact on the must and finished wine.
What are tendrils?
The shoot cannot support itself, therefore vines have tendrils. Tendrils attach the vine to other plants or trees, providing support
What are the functions of tendrils in viticulture?
In viticulture, grape growers can use a trellis to position the vine canopy. The tendrils curl around trellis wires and keep the canopy in place.
What is the function of leaves?
The leaves are the main site of photosynthesis in the vine.
The sugars produced in photosynthesis are used for vine growth and metabolism.
Define stomata
Stomata are pores, found in the epidermis of leaves, stems, and other organs, that facilitate gas exchange.