Vine Anatomy

Question 1

Species of grape most commonly used for winemaking?

Answer 1

Vitis vinifera

Question 2

What is the origin of vitis vinifera?

Answer 2

Eurasia

Question 3

The four most common N. American grape species?

Answer 3

1. Vitis labrusca
2. Vitis riparia
3. Vitis berlandieri
4. Vitis rupestris

Question 4

What are N. American grape species mostly used for?

Answer 4

Rootstocks onto which v. vinifera is grafted

Question 5

What are the four main sections of a Vine?

Answer 5

1. Main shoots
2. One-year-old wood
3. Permanent wood
4. Roots

Question 6

Of what does the canopy consist?

Answer 6

The main shoots and all of their major structures – stem, buds, leaves, lateral shoots, tendrils, and inflorescences/grape bunches

Question 7

What is the function of the main axis of the shoot?

Answer 7

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.

Question 8

What are nodes and internodes?

Answer 8

Nodes: the little swellings along the stem, where the other structures are attached

Internodes: the lengths of stem in between the nodes

Question 9

What are canes?

Answer 9

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.

Question 10

What are buds and where do they form?

Answer 10

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.

Question 11

What are the two types of buds?

Answer 11

Compound buds and prompt buds

Question 12

What are compound buds?

Answer 12

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).

Question 13

What are prompt buds?

Answer 13

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)

Question 14

What is a lateral shoot?

Answer 14

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.

Question 15

Why is a lateral shoots growing near the base of the main shoot undesirable?

Answer 15

They impede air flow

They may shade the fruit too much.

Question 16

What is a second crop on lateral shoots?

Answer 16

Lateral shoots often produce inflorescences

These inflorescences become bunches of grapes later than those on the main stem and hence ripen later.

Question 17

What are the problems with a secondary crop from lateral shoots?

Answer 17

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

Question 18

What’s the benefit of hand harvesting when it comes to the second crop?

Answer 18

You can be selective and pick the second crop later instead of mixing.

Question 19

What is the function of the vine tendrils?

Answer 19

Tendrils support the vine and they curl around trellis wires and keep the canopy in place.

Question 20

What is the function of a vine’s leaves?

Answer 20

Leaves are the site of photosynthesis. They are also the site of stomata.

Question 21

What is the purpose of stomata?

Answer 21

Pores on the underside of the leaves.

They let water diffuse out

They let CO2 in

They close if the vine is water stressed

Question 22

What is an inflorescence?

Answer 22

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.

Question 23

What are the three parts of the grape?

Answer 23

1. Pulp
2. Skin
3. Seeds

Question 24

What does grape pulp contain?

Answer 24

Water, sugars, acids, and some aroma compounds and precursors

Question 25

What color is most pulp? What is the exception?

Answer 25

The pulp of most grapes is colorless.

Exceptions are teinturier Varietals, which have red pulp, but are not common

Question 26

What do the skins contain?

Answer 26

The skin of the grape contains a high concentration of aroma compounds and aroma precursors, tannins, and color compounds

Question 27

What do the seeds contain? What color are the seeds?

Answer 27

Seeds contain oils, tannins, and the embryo, which can grow into a new plant.

Seeds mature inside the grape, turning yellow to dark brown.

Question 28

What is the bloom?

Answer 28

A powdery waxy coating that covers the surface of the grape.

Question 29

What is one-year-old wood?

Answer 29

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.

Question 30

What is the permanent wood?

Answer 30

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.