Deck 26: Secondary Growth in Stems

Question 1

Which of the following is/are dead at maturity?

A) phellogen
B) fusiform initials
C) ray initials
D) phellem
E) vascular rays

Answer 1

D

Question 2

As the vascular cambium continues to divide, the cambial cells:

A) are displaced inward.
B) are displaced outward.
C) remain in their original location.
D) cease to divide periclinally.
E) cease to divide anticlinally.

Answer 2

B

Question 3

The periderm consists of:

A) phellem only.
B) phellogen only.
C) phelloderm only.
D) phellem and phellogen only.
E) phellem and phellogen, and phelloderm.

Answer 3

E

Question 4

At the end of the first year's secondary growth, immediately inside the secondary phloem is the:

A) primary phloem.
B) periderm.
C) vascular cambium.
D) cortex.
E) secondary xylem.

Question 5

In most woody plants, the first periderm usually arises in the:

A) cortex.
B) epidermis.
C) primary phloem.
D) primary xylem.
E) pith.

Question 6

Secondary growth in the Tilia stem is different from that in the Sambucus stem because in the Tilia stem:

A) more secondary xylem than secondary phloem is formed.
B) more secondary phloem than secondary xylem is formed.
C) only a small amount of secondary tissue is produced.
D) dilated phloem rays are formed.
E) phloem fibers are formed.

Question 7

The cells that comprise the vascular cambium are the ___________ and the ______________.

A) axial rays; vascular rays
B) axial rays; fusiform initials
C) vascular rays; fusiform initials
D) fusiform initials; ray initials
E) vascular rays; ray initials

Question 8

Which of the following statements about lenticels is FALSE?

A) They are found only on roots and stems.
B) They are portions of the periderm.
C) They contain numerous intercellular spaces.
D) In stems they generally arise below stomata.
E) On the surface of stems they appear as raised areas.

Question 9

The cambial zone consists of:

A) the fusiform initials only.
B) the ray initials only.
C) the fusiform initials and ray initials only.
D) the fusiform initials, the ray initials, and their immediate derivatives only.
E) the fusiform initials, the ray initials, their immediate derivatives, and the vascular rays.

Question 10

At the end of the first year's growth, bark is composed of:

A) periderm.
B) cork.
C) all tissues outside the vascular cambium.
D) only secondary tissues.
E) only primary tissues.

Question 11

Lenticels function primarily in:

A) water transport.
B) gas exchange.
C) mineral uptake.
D) protection.
E) hormone production.

Question 12

Cambial initials produce ______ cells toward the outside and ______ cells toward the inside.

A) ray; phloem
B) phloem; phloem
C) xylem; xylem
D) xylem; ray
E) phloem; xylem

Question 13

Which of the following statements about vascular rays is FALSE?

A) They are composed largely of parenchyma cells.
B) They serve as barriers to the movement of food substances and water.
C) They store starch, proteins, and lipids.
D) They synthesize secondary products.
E) They are variable in length.

Question 14

At the end of the first year's secondary growth, immediately outside the primary xylem is the:

A) primary phloem.
B) secondary phloem.
C) vascular cambium.
D) pith.
E) secondary xylem.

Question 15

Which of the following statements about woody perennials is FALSE?

A) Some form dormant rhizomes or bulbs during unfavorable seasons.
B) They include trees and shrubs.
C) Some flower before they become adult plants.
D) Some are deciduous.
E) Some live for many years.

Question 16

In the southern hemisphere, biennials:

A) are represented by weeds.
B) are annuals.
C) form seeds and flowers in the same growing season.
D) usually become woody.
E) complete their life cycle in two calendar years.

Question 17

Interfascicular cambium arises:

A) in the pith rays.
B) between the primary xylem and primary phloem.
C) in the cortex.
D) between the primary xylem and secondary xylem.
E) between the primary phloem and secondary phloem.

Question 18

Which of the following statements about secondary growth is FALSE?

A) It results from the activity of the vascular cambium and the cork cambium.
B) It is responsible for the increase in girth of a plant.
C) It can occur simultaneously with primary growth.
D) Most monocots exhibit considerable secondary growth.
E) Herbaceous plants undergo little or no secondary growth.

Question 19

In secondary tissues, the axial system consists of ______ cells and the radial system consists of ______ cells.

A) parenchyma; phloem
B) parenchyma; xylem
C) xylem; phloem
D) xylem and phloem; ray
E) ray; xylem and phloem

Question 20

Which of the following statements about secondary growth is FALSE?

A) The secondary vascular tissues form a cylindrical shape.
B) Vascular rays extend radially through the secondary xylem and secondary phloem.
C) Primary phloem fibers remain intact longer than other primary phloem cells.
D) The primary phloem is pushed outward.
E) Most plants produce more secondary phloem than secondary xylem.

Question 21

Compression wood:

A) develops on the upper side of a leaning stem.
B) is produced by increased cambial activity on the lower side of a leaning stem.
C) is the reaction wood found in angiosperms.
D) is characterized by wider portions of growth rings on the upper side of the stem.
E) has less lignin and more cellulose than normal wood.

Question 22

After the first periderm is formed, additional periderms originate from ______ cells.

A) epidermal
B) pith
C) cortical
D) phloem parenchyma
E) xylem parenchyma

Question 23

Which of the following is found in the outer bark but not the inner bark?

A) xylem
B) pith
C) cork
D) phelloderm
E) phloem

Question 24

Ring-porous woods are different from diffuse-porous woods because in ring-porous woods:

A) the pores of late wood are larger than those of early wood.
B) the pores of early wood are larger than those of late wood.
C) the pores are fairly uniform in size throughout the growth layer.
D) almost all the water is conducted in the innermost growth layer.
E) vessels are lacking.

Question 25

How many rings of vascular cambium would be found in a tree that is 6 years old?

A) 0
B) 1
C) 2
D) 3
E) 6

Question 26

Which of the following statements about tyloses is FALSE?

A) They may inhibit the spread of pathogens through the xylem.
B) Their formation may be induced by plant pathogens.
C) They may completely block a vessel.
D) They are balloon-like outgrowths from pit membranes.
E) They are formed when vessels become nonfunctional.

Question 27

Which of the following statements about growth rings is FALSE?

A) They may be absent in trees growing in the tropics.
B) They are caused by variations in the activity of the vascular cambium in each growing season.
C) They may occur in secondary phloem as well as in secondary xylem.
D) An annual ring represents one season's growth.
E) A false annual ring represents growth in an unusually short growing season.

Question 28

Unlike ring bark, scale bark:

A) is found in honeysuckle (Lonicera).
B) is found in grape (Vitis).
C) contains cork.
D) contains concentric rings of periderms.
E) contains discontinuous layers of periderms.

Question 29

In wood having a high specific gravity, the fibers have ______ walls and ______ lumens.

A) thin; variable
B) thin; narrow
C) thin; wide
D) thick; narrow
E) thick; wide

Question 30

______ is thought to block the movement of water or gases through a pit-pair in conifer tracheids.

A) Resin
B) The pit membrane
C) The middle lamella
D) A torus
E) A resin duct

Question 31

In angiosperms, early wood ______ than late wood.

A) has narrower cells
B) has thicker cell walls
C) is denser
D) is produced later in the growing season
E) may have much larger pores

Question 32

Angiosperm wood differs from conifer wood in that angiosperm wood has:

A) tracheids.
B) vessels.
C) orderly radial files of cells.
D) smaller rays.
E) fewer cell types in the axial system.

Question 33

Biennials form roots, stems, leaves and flowers in the first growing season and seeds in the second season.

Question 34

Wood contains mostly:

A) primary phloem
B) secondary phloem.
C) primary xylem.
D) secondary xylem.
E) periderm.

Question 35

Which of the following statements about resin ducts is FALSE?

A) They may result from trauma.
B) They secrete resin that may protect against fungi and beetles.
C) They are intercellular spaces lined with collenchyma cells.
D) Their formulation may be stimulated by wounding.
E) In Pinus they occur in both the axial system and the rays.

Question 36

Heartwood is different from sapwood in that heartwood:

A) has a lighter color.
B) is nonconducting.
C) contains living cells.
D) is older.
E) is found closer to the vascular cambium.

Question 37

"Softwood" is the name given to wood:

A) found in conifers.
B) found in eudicots.
C) composed of functional phloem.
D) composed of primary xylem.
E) having no commercial value.

Question 38

Conducting phloem:

A) is composed of primary tissue.
B) is part of the inner bark.
C) functions primarily to store foods.
D) consists of living or dead sieve elements.
E) makes up the majority of secondary phloem in older plants.

Question 39

In the southern hemisphere, a biennial can correctly be called a winter annual.

Question 40

Which of the following could never be part of the bark?

A) cortex
B) secondary xylem
C) primary phloem
D) secondary phloem
E) phelloderm

Question 41

Reactivation of the vascular cambium in the spring is triggered by the expansion of the buds.

Question 42

Fascicular cambium arises from procambium immediately outside the vascular bundles.

Question 43

Primary phloem would not normally be part of the bark.

Question 44

The cortex of the stem is usually sloughed during the first year of growth.

Question 45

The genes that regulate secondary growth are entirely different from those that regulate primary growth.

Question 46

In many woody roots and stems, only the secondary phloem in the current growth ring is active in long-distance food transport.

Question 47

Bark may contain primary tissues as well as secondary tissues.

Question 48

A radial section and a tangential section are longitudinal sections.

Question 49

Hardwood is another name for angiosperm wood.

Question 50

The cambial zone consists of the fusiform initials and their immediate derivatives.

Question 51

Conifer wood typically contains more parenchyma than angiosperm wood.

Question 52

New ray initials are produced by the fusiform initials.

Question 53

The order of tissues in the periderm, from the center of the plant toward the outside, is cork, cork cambium and phelloderm.

Question 54

Woody perennials usually keep growing during unfavorable seasons.

Question 55

In secondary tissues, the cells of the axial system are oriented vertically and those of the radial system are oriented horizontally.

Question 56

The meristematic cells of the vascular cambium are the fusiform initials and the interfascicular initials.

Question 57

The stem and root of most woody plants usually contains only one periderm.

Question 58

In the elderberry stem during its first year of secondary growth, all primary phloem cells are destroyed.

Question 59

All the periderms make up the outer bark.

Question 60

In the cork oak, the cork produced by the first cork cambium has the least commercial value.

Question 61

Growing seasons with favorable environmental conditions produce narrower growth rings than seasons with unfavorable conditions.

Question 62

Early wood is more dense than late wood.

Question 63

In diffuse-porous woods, the pores are fairly uniform in size and distribution throughout the growth layers.

Question 64

Compression wood is a type of reaction wood found in angiosperms.