Lab 3

Question 1

secondary structure

Answer 1

structure that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken
occurs in most seed plants; monocots usually lack secondary growth

Question 2

dedifferentiation

Answer 2

transient process by which cells become less specialized and return to an earlier cell state within the same lineage
results in increase in cell potency, meaning that, following dedifferentiation, a cell may possess the ability to re-differentiate into more cell types; dedifferentiation often occurs in response to injury or stress, allowing cells to regenerate and differentiate into new cell types

Question 3

phellogen/cork cambium

Answer 3

type of lateral meristem in plants responsible for producing phellem toward the outside and sometimes phelloderm toward the inside; contributes to the formation of the outer protective tissue layer called periderm

Question 4

phelloderm

Answer 4

parenchyma tissue produced inwardly by the phellogen during secondary growth; located between the phellem and the secondary phloem

Question 5

phellem/cork

Answer 5

outer protective tissue produced by phellogen during secondary growth in plants; forms the outermost layer of the periderm

Question 6

periderm

Answer 6

protective tissue that replaces the epidermis in older stems and roots during secondary growth; consists of phellem, phellogen, and sometimes phelloderm

Question 7

lenticel

Answer 7

small, raised area in the bark of woody stems and roots that allows for gas exchange between the internal tissues and the external environment

Question 8

rhytidome

Answer 8

outermost layer of bark on older woody stems and roots, consisting of dead tissues such as phellem, phellogen, and phelloderm

Question 9

intercellular space

Answer 9

space between plant cells where gases, water, and nutrients can move freely

Question 10

storage parenchyma

Answer 10

parenchyma cells in plants that store reserve materials such as starch, oils, and proteins

Question 11

interfascicular cambium

Answer 11

type of lateral meristem found between the vascular bundles in some plants, responsible for producing secondary xylem and phloem during secondary growth; differentiates from parenchyma or collenchyma cells located between the vascular bundles

Question 12

fascicular cambium

Answer 12

a lateral meristem found within vascular bundles in plants, responsible for producing secondary xylem and phloem during secondary growth; differentiates from procambium located between the primary xylem and the primary phloem of individual vascular bundles

Question 13

fusiform initial

Answer 13

elongated tapering cells that give rise to all cells of the vertical system of the secondary phloem and xylem (secondary tracheary elements, fibres, and sieve cells and the associated companion cells)

Question 14

ray initial

Answer 14

isodiametric cells - shorter than fusilorm initial cells - that produce the vascular rays, which constitute the horizontal system of secondary tissues

Question 15

secondary xylem

Answer 15

wood formed by the vascular cambium during secondary growth, consisting primarily of tracheids and vessel elements that conduct water and provide structural support

Question 16

primary xylem

Answer 16

first-formed xylem tissue in a plant, derived from the procambium during primary growth

Question 17

simple pit

Answer 17

small, simple opening in the cell wall of adjacent plant cells, allowing for the passage of water and solutes between cells

Question 18

bordered pit

Answer 18

type of pit in the cell wall of certain plant cells, characterized by a thickened, often elaborate border that helps regulate the flow of water between cells

Question 19

torus

Answer 19

structure found within bordered pits, consisting of a thickened area in the center of the pit membrane; prevents air from spreading between tracheids

Question 20

early wood

Answer 20

portion of a tree growth ring formed during the early part of the growing season, characterized by larger, thinner-walled cells

Question 21

late wood

Answer 21

portion of a tree growth ring formed during the later part of the growing season, characterized by smaller, thicker-walled cells

Question 22

growth ring

Answer 22

distinct layer of wood formed during one annual growing season, visible as a ring in the cross-section of a tree trunk

Question 23

annual ring boundary

Answer 23

boundary between adjacent growth rings in the wood of a tree, representing the end of one growing season and the beginning of the next

Question 24

ring-porous wood

Answer 24

type of wood in which the size of the conducting vessels varies significantly between early and late wood, resulting in the formation of distinct growth rings

Question 25

diffuse-porous wood

Answer 25

type of wood in which the size of the conducting vessels remains relatively uniform throughout the growth rings, without distinct differences between early and late wood

Question 26

sapwood

Answer 26

outer, living portion of wood in a tree, responsible for conducting water and nutrients from the roots to the leaves

Question 27

hardwood

Answer 27

wood of broad-leaved dicotyledonous trees, such as oak, beech, ash, as distinguished from the wood of a conifer

Question 28

pith/medullary ray

Answer 28

radial structures extending from the pith to the bark, consisting of parenchyma cells that transport water and nutrients radially through the stem

Question 29

ray

Answer 29

radial structure extending from the pith to the bark, consisting of parenchyma cells that transport water and nutrients radially through the stem

Question 30

pith/medulla

Answer 30

central, spongy tissue found in the center of stems and branches, surrounded by vascular tissues

Question 31

secondary phloem

Answer 31

phloem tissue produced by the vascular cambium during secondary growth, responsible for conducting sugars and other organic nutrients throughout the plant

Question 32

primary phloem

Answer 32

first-formed phloem tissue in a plant, derived from the procambium during primary growth

Question 33

ray dilatation

Answer 33

radial expansion of rays in woody plants, often occurring during periods of active growth

Question 34

resin canal

Answer 34

tubular structures found in the tissues of some plants, especially conifers, responsible for producing and transporting resin

Question 35

tree

Answer 35

woody perennial plant typically characterized by a single main stem or trunk, supporting branches and leaves above ground

Question 36

shrub

Answer 36

woody plant with multiple stems, usually shorter than a tree and often branching close to the ground

Question 37

herb

Answer 37

non-woody plant with a soft stem that dies back to the ground at the end of the growing season

Question 38

heartwood

Answer 38

inner, older, non-living wood in the center of a tree trunk or branch, often darker in color and denser than the surrounding sapwood, due to the accumulation of extractives and deposition of compounds like tannins and resins