Vine Anatomy

Question 1

Which species of grape is most commonly used for winemaking?

Answer 1

Vitis Vinifera

Question 2

Where did this V. vinifera originate?

Answer 2

Eurasia

Question 3

What are the four most common North American grape species?

Answer 3

1. Vitis Riparia
2. Vitis Labrusca
3. Vitis Berlandieri
4. Vitis Rupestris

Question 4

What are North American grape species mostly used for?

Answer 4

Rootstocks onto which Vitis 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. permantent 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

1. Transports water and solutes (sugars and minerals) to and from the different structures
2. 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

Green shoots that turned brown and lignified in late summer after the leaves have fallen

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

1. Compound buds
2. 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 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).

Question 13

What are Prompt buds?

Answer 13

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.

Question 13

What is a lateral shoot?

Answer 13

• 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

Question 14

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

Answer 14

• They impede air flow
• They may shade the fruit too much.

Question 15

What is a second crop on lateral shoots?

Answer 15

• Lateral shoots often produce inflorescences.
• These inflorescences become bunches of grapes later than those on the main stem and hence ripen later.

Question 16

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

Answer 16

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

Question 17

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

Answer 17

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

Question 18

What is the function of the vine tendrils?

Answer 18

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

Question 19

What is the function of a vine’s leaves?

Answer 19

Leaves are the site of photo synthesis. They are also the site of stomata.

Question 20

What is the purpose of stomata?

Answer 20

• Pores on the underside of the leaves
• Let water diffuse out (Transpiration)
• Let CO2 in
• Close if the vine is water stressed

Question 21

What is an inflorescence?

Answer 21

• 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.

Question 22

What are the three parts of a grape?

Answer 22

1. the skin
2. the pulp
3. the seeds

Question 23

What does grape pulp contain?

Answer 23

It contains water, sugars, acids and some aroma compounds and aroma precursors.

Question 24

What colour is most pulp? What is the exception?

Answer 24

• The pulp of most grapes is colourless.
• Exceptions: teinturier varieties, which have red-coloured pulp (e.g. Alicante Bouschet) not common.

Question 25

What do the skins contain?

Answer 25

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

Question 26

What do the seeds contain? What colour are the seeds?

Answer 26

• 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 27

What is the bloom?

Answer 27

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

Question 28

What is One-Year-Old Wood?

Answer 28

• 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 29

What is permanent wood?

Answer 29

• 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.