Module 12 - Secondary Growth

Question 1

Wood is composed of?

Answer 1

Secondary Xylem

Question 2

3 planes of view of wood

Answer 2

Tangential, radial, and transverse

Question 3

Vessel members that transport materials longitudinally

Answer 3

Axial system

Question 4

Transports materials radially

Answer 4

Ray system

Question 5

Types of rays

Answer 5

Multiseriate - marami cells

Uniseriate - isang line ng rays lang

Question 6

Structure of bark that permits the passage of gas inward and outward of the plant

Consists of loosely packaged parenchyma cells

Living, require oxygen

Answer 6

Lenticels

Question 7

Parts of the periderm

Answer 7

Cork (Phellem)
Cork Cambium (Phellogen)
Phelloderm

Question 8

• increase in length of the shoot and the root
• the result of cell division in the apical meristems and elongation of cells

Answer 8

1°ry Growth

Question 9

• characterized by an increase in thickness or girth - caused by cell division in the lateral meristems

Answer 9

2°ry Growth

Question 10

mostly undergo 1°ry growth, with little 2°ry growth

Answer 10

Herbaceous plants

Question 11

• 2°ry growth produces wood (dicots & gymnosperms, rarely in monocots)
• No 2°ry growth in Lycophyta and Pterophyta

Answer 11

Woody plants

Question 12

• Found exclusively in roots and stems.
• Responsible for secondary growth, leading to an increase in the girth of the organ.
• Classified as secondary meristems, as they develop entirely or partly from differentiated tissues.

Answer 12

Lateral Meristem

Question 13

gives rise to secondary xylem and phloem

Answer 13

Vascular Cambium

Question 14

Gives rise to cork and phelloderm

Answer 14

Cork Cambium

Question 15

Conditions for the origin of vascular cambium

Answer 15

• If all procambial cells differentiate into primary vascular tissues, no vascular cambium is formed.
• If some procambium remains in a meristematic state after primary growth, it becomes the vascular cambium.
• Vascular cambium may also originate from differentiated tissues, such as pericycle and interfascicular parenchyma, not just residual procambium.

Question 16

portion of the vascular cambium that develops within the vascular bundles; it originates from residual procambium

Answer 16

Fascicular Cambium

Question 17

portion of the vascular cambium that develops between the vascular bundles; it originates from interfascicular parenchyma

Answer 17

Interfascicular Cambium

Question 18

• Cells divide anticlinally to produce more cambial cells.
• Cells divide periclinally; the inner cell differentiates into secondary xylem, while the outer cell differentiates into secondary phloem.

Answer 18

Vascular Cambium Cells

Question 19

Gives rise to 2°ry Xylem inward & 2°ry Phloem outward

Answer 19

Vascular Cambium

Question 20

2 Cell Types in the Vascular Cambium

Answer 20

1. Fusiform initials - tall, axially oriented cells; give rise to the axial xylem and phloem
2. Ray initials – smaller, round to angular in shape; give rise to xylem and phloem rays

• Both are densely cytoplasmic with thin bodies

Question 21

It serves as a protective tissue, replacing the epidermis.

In herbaceous dicots, it is typically limited to the oldest parts of the root or stem.

Monocots usually lack a well-developed protective tissue, often having storied cork or none at all.

It is a component of the bark, constituting all tissues outside the vascular cambium.

Answer 21

Periderm

Question 22

cork cambium, a lateral meristem, unlike vascular cambium has only 1 type of initial cells.

In stems, it can arise from epidermis, cortex or phloem and in roots, from the pericycle

Produces the periderm

Outer product is the cork/phellem, inner product is the phelloderm

Answer 22

Phellogen

Question 23

Arranged in compact rows without intercellular spaces.

Primary wall composed of cellulose, sometimes with lignin or suberin.

The suberin layer is impermeable to gases and water, resistant to the action of acids.

Ultimately, these cells become dead.

Answer 23

Phellem

Question 24

Living cells with non-suberized walls.

Some parenchyma cells may store starch.

In certain cases, parenchyma cells contain chloroplasts and are photosynthetic.

Sclereids may be present in some parenchyma tissues.

Answer 24

Phelloderm

Question 25

Is wood that, due to a natural chemical transformation, becomes more resistant to decay through a genetically programmed process.

Once the formation is complete, they are typically dead, providing structural support to the tree.

Answer 25

Heartwood

Question 26

Other term for Heartwood

Answer 26

Duramen

Question 27

Is the younger, outermost wood in a tree.

It consists of living cells, including xylem tracheids and vessels, which are responsible for the conduction of water and nutrients.

Answer 27

Sapwood

Question 28

Other term for sapwood

Answer 28

Alburnum

Question 29

T/F Heartwood results from the plant’s response to decay, where xylem vessels are blocked with gums, resins, and waxes, by-products of photosynthesis.

Answer 29

True

Question 30

T/F Xylem elements in heartwood contain tyloses.

Answer 30

True

Question 31

T/F High levels of volatile organic compounds, specifically terpenes, are present in heartwood, acting as a defense against tree pathogens such as bacteria, fungi, and insect larvae.

Answer 31

True

Question 32

T/F Heartwood, or injured portions of the plant, is protected from decay as long as terpene levels remain sufficiently high to deter or control pathogens.

Answer 32

True

Question 33

If parenchyma cells in the secondary phloem divide and expand, it is called

Answer 33

Expansion Tissue

Question 34

Consist of successive increments of xylem produced by the cambium.

Comprises early wood (formed in the early part of the growing season) and late wood (formed later in the season).

The transition between the late wood of one season and the early wood of the following season is typically marked by a sharp division line.

Answer 34

Annual Rings

Question 35

What sectioning is it if all you see are similar looking squares filled with circles?

Answer 35

Cross/transverse

Question 36

If it looks like striated muscles, what kind of wood section is it?

Answer 36

Radial

Question 37

Stem wood section that looks like striated muscles with pouches of bubbles in it

Answer 37

Tangential

Question 38

occurs when cells in the residual procambium and parts of the pericyle begin to undergo periclinal divisions

Answer 38

Initiation of 2°ry growth

Question 39

T/F In secondary growth of roots, only the pericyle cells opposite the xylem poles start to divide periclinally

Answer 39

True

Question 40

In secondary growth of roots, the inner layer of cells becomes the _____. The outer layer is retained as _______.

Answer 40

Vascular Cambium; Pericycle

Question 41

Last slide na, aral na lang the pics or slides :>

Answer 41

Ayoko naaaaaaaaa