Ch. 26 Woody Stems

Question 1

Describe the difference between annual, biennial, and perennial

Answer 1

Annual plants complete their life cycle within one year. They germinate, grow, flower, produce seeds, and die in a single growing season. Examples include marigolds and zinnias.

Biennial: Biennial plants have a two-year life cycle. In the first year, they typically grow vegetatively, producing leaves and stems. In the second year, they flower, set seeds, and then die. Common biennials include carrots and parsley.

Perennial: Perennial plants live for multiple years, often regrowing from the same roots or stems each year. They can continue to produce flowers and seeds over several seasons. Trees, shrubs, and many herbaceous plants like roses and daisies are perennials.

Question 2

Describe the difference between primary growth and secondary growth.

Answer 2

Primary Growth: Primary growth is vertical growth of a plant, occurring at the tips of roots and stems. lengthening of plant parts of apical meristems, which are primarily responsible for cell division and elongation. Primary growth produces primary tissues like primary xylem and phloem.

Secondary growth is the lateral or radial growth of a plant, increasing its girth or width. It occurs in woody plants and is driven by lateral meristems, primarily the vascular cambium and cork cambium. Secondary growth results in the formation of secondary tissues like secondary xylem and phloem, cork, and secondary cortex.

Question 3

Compare and contrast the two lateral meristems: Where are they found? What do they produce?

Answer 3

Vascular Cambium:

Location: The vascular cambium is found between the primary xylem and phloem in the stem and roots of woody plants.
Products: Vascular cambium produces secondary xylem (wood) toward the inside and secondary phloem toward the outside.
Cork Cambium (Phellogen):

Location: Cork cambium is located in the outer bark of woody stems and roots.
Products: Cork cambium produces cork cells (phellem) to the outside and phelloderm to the inside, which together form the periderm.

Question 4

Define Bark .

Answer 4

The protective outer covering of a woody stem or branch.

Question 5

define outer bark

Answer 5

The protective, dead cork (phellem) and cork cambium (phellogen).

Question 6

define lenticel

Answer 6

Small, corky pores in the bark that allow for gas exchange.

Question 7

define cork

Answer 7

The outermost layer of the periderm, formed by the cork cambium.

Question 8

define wood

Answer 8

: The secondary xylem produced during secondary growth.

Question 9

define heartwood

Answer 9

The older, non-functional core of wood in a tree trunk.

Question 10

define sapwood

Answer 10

The younger, functional outer portion of wood that transports water and nutrients.

Question 11

define inner bark

Answer 11

The living layer of phloem and associated tissues.

Question 12

define rays,

Answer 12

: Radial bands of parenchyma cells that extend from the center to the bark in wood.

Question 13

define girdling

Answer 13

: Removing a ring of bark around a tree, which can kill it by interrupting nutrient flow.

Question 14

define dendrochronology

Answer 14

The study of tree rings to determine age, growth patterns, and environmental history.

Question 15

define dendroclimatology

Answer 15

Using tree rings to study past climate conditions.

Question 16

Identify the parts of a cross-section of a woody stem

Answer 16

A cross-section of a woody stem includes the pith, primary xylem, secondary xylem, vascular cambium, secondary phloem, primary phloem, and bark (cork cambium, cork, and phelloderm).