Vine Anatomy Flashcards
Species of grape most commonly used for winemaking?
Vitis vinifera
What is the origin of vitis vinifera?
Eurasia
The four most common N. American grape species?
- Vitis labrusca
- Vitis riparia
- Vitis berlandieri
- Vitis rupestris
What are N. American grape species mostly used for?
Rootstocks onto which v. vinifera is grafted
What are the four main sections of a Vine?
- Main shoots
- One-year-old wood
- Permanent 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 to and from the different structures (solutes are substances that dissolve in a liquid to form a solution and in this instance includes sugars and minerals). 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?
In late summer, the leaves fall from the vine and the green shoots lignify (becoming woody and rigid) and turn brown; from this point they are called canes.
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 and 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 buds, 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 shoots (that has just grown from a compound buds) 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 and additional source of leaves for photosynthesis.
Why is a lateral shoots 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/flavors
in black grapes, they may have less color
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 photosynthesis. They are also the site of stomata.
What is the purpose of stomata?
Pores on the underside of the leaves.
They let water diffuse out
They let CO2 in
They 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 shoots can depend on the grape variety, but is usually between one and three.
What are the three parts of the grape?
- Pulp
- Skin
- Seeds
What does grape pulp contain?
Water, sugars, acids, and some aroma compounds and precursors
What color is most pulp? What is the exception?
The pulp of most grapes is colorless.
Exceptions are teinturier Varietals, which have red pulp, but are not common
What do the skins contain?
The skin of the grape contains a high concentration of aroma compounds and aroma precursors, tannins, and color compounds
What do the seeds contain? What color 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 the 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 other parts of the vine.
They transport water and solutes to and from different parts of the vine and store carbohydrates and nutrients.
