Chapter 35

Front 1

Periderm

Back 1

Replaces the epidermis in older regions of stems and roots.

Front 2

Epidermis

Back 2

The outer layer of tightly packed cells in nonwoody plants.

Front 3

Cuticle

Back 3

A waxy epidermal coating in leaves and most stems that prevents water loss.

Front 4

Trichomes

Back 4

Highly specialized cells found in plant shoots.

Front 5

Xylem

Back 5

Conducts water and dissolved minerals upward from the roots to the shoots.

Front 6

Phloem

Back 6

Transports sugars and organic materials from where they are made to the area where they are needed.

Front 7

Stele

Back 7

The vascular tissue of a root or stem.

Front 8

Pith

Back 8

Ground tissue that is internal to the vascular tissue in plants.

Front 9

Cortex

Back 9

Ground tissue that is external to the vascular tissue.

Front 10

Parenchyma cells

Back 10

Made of thin walls and lack secondary walls. They perform the metabolic functions of the plant.

Front 11

Collenchyma cells

Back 11

Support young parts of the plant shoot.

Front 12

Schlerenchyma cells

Back 12

Supporting cells that are more rigid than collenchyma cells.

Front 13

Lignin

Back 13

A strengthening polymer that accounts for 1/4 of the mass of wood.

Front 14

Tracheids

Back 14

Occur in the xylem of all vascular plants.

Front 15

Sieve-tube elements

Back 15

The part of the phloem where nutrients are passed through. They lack a nucleus and ribosomes etc.

Front 16

Lignin

Back 16

A strengthening polymer that accounts for 1/4 of the mass of wood.

Front 17

Tracheids

Back 17

Occur in the xylem of all vascular plants.

Front 18

Indeterminate growth

Back 18

Growth that occurs throughout the lifecycle of an organism--particularly in plants.

Front 19

Meristems

Back 19

Unspecialized tissues that divide when the conditions are right.

Front 20

Determinate growth

Back 20

Organs/organisms that stop growing after they reach a certain size.

Front 21

Apical meristems

Back 21

Provide cells that enable plants to grow in length.

Front 22

Primary growth

Back 22

Plant growth in length.

Front 23

Lateral meristems

Back 23

Provide cells that enable plants to grow in thickness.

Front 24

Secondary growth

Back 24

Plant growth in thickness.

Front 25

Vascular cambium

Back 25

Adds layers of secondary xylem and secondary phloem in secondary growth.

Front 26

Cork cambium

Back 26

Replaces the epidermis with periderm in secondary growth.

Front 27

Annual plants

Back 27

Plants that complete their life cycle in one year.

Front 28

Biennial plants

Back 28

Plants that require two growing seasons to complete their life cycle.

Front 29

Perennial plants

Back 29

Plants that live for many years.

Front 30

Endodermis

Back 30

The innermost layer of the cortex. It is one cell thick and forms a boundary with the vascular cylinder.

Front 31

Pericycle

Back 31

The outermost cell layer of the vascular cylinder.

Front 32

Leaf primordia

Back 32

Cow-horn shaped projections that emerge from the sides of the shoot apical meristem.

Front 33

Apical dominance

Back 33

The closer an axillary bud is to an active apical bud, the more inhibited it is. It can be overruled by photosynthetic priorities.

Front 34

Intercalary meristems

Back 34

Structures that allow damaged leaves to regrow, particularly in monocots.

Front 35

Stomata

Back 35

Pores in the epidermis of plants that allows exchange of carbon dioxide and oxygen between the surrounding air and the photosynthetic cells in the leaf. They also promote evaporative loss of water.

Front 36

Guard cells

Back 36

The cells that plank stomata. They consist of two specialized epidermal cells and regulate the opening and closing of the pore.

Front 37

Mesophyll

Back 37

Ground tissue in a leaf which is sandwiched between the upper and lower epidermal layers.

Front 38

Palisade mesophyll

Back 38

Mesophyll that has one or more layers of elongated parenchyma cells on the upper part of the leaf.

Front 39

Spongy mesophyll

Back 39

Mesophyll that is below the palisade mesophyll. They are more loosely arranged allowing carbon dioxide and oxygen to flow around the cells.

Front 40

Bundle sheath

Back 40

A layer of cells that regulates the movement of substances between the vascular tissue and the mesophyll.

Front 41

Vascular rays

Back 41

Radial files of mostly parenchyma cells that connect the secondary xylem and phloem. They move nutrients between the secondary xylem and phloem, store carbohydrates, and aid in wound repair.

Front 42

Dendrochronology

Back 42

The science of analyzing tree growth ring patterns.

Front 43

Heartwood

Back 43

Layers of xylem that no longer transport water and minerals and are closer to the center of the stem or root.

Front 44

Sapwood

Back 44

The newer, outer layers of xylem that still transport xylem sap.

Front 45

Suberin

Back 45

The waxy, hydrophobic material that mature cork cells deposit.

Front 46

Lenticels

Back 46

Small, raised areas that create space between cork cells to allow for the exchange of gasses with the outside air.

Front 47

Bark

Back 47

All tissues external to the vascular cambium.

Front 48

Development

Back 48

The specific series of changes by which cells form tissues, organs, and organisms.

Front 49

Developmental plasticity

Back 49

The ability to alter form in response to local environment conditions.

Front 50

Growth

Back 50

An irreversible increase in size.

Front 51

Morphogenesis

Back 51

The process that gives a tissue, organ, or organism its shape and determines the positions of cell types.

Front 52

Cell differentiation

Back 52

The process by which cells with the same genes become different from one another.

Front 53

Preprophase band

Back 53

Microtubules in the cytoplasm become concentrated into a ring.

Front 54

Symmetry of cell division

Back 54

The distribution of cytoplasm between daughter cells.

Front 55

Asymmetrical cell division

Back 55

One daughter cells receives more cytoplasm than the other during mitosis.

Front 56

Polarity

Back 56

The condition of having structural or chemical differences at opposite ends of an organism.

Front 57

Pattern formation

Back 57

The development of specific structures in specific locations.

Front 58

Hox genes

Back 58

Genes that encode transcription factors and are critical for the proper number and placement of embryonic structures.

Front 59

Arabidopsis

Back 59

Root hair cells and hairless epidermal cells.

Front 60

Phase changes

Back 60

The morphological changes that arise from plant developmental activity in the shoot apical meristem.

Front 61

Floral meristem identity genes

Back 61

The genes that are switched on to transition from vegetative, indeterminate growth to flowering growth in plants.

Front 62

Plant organ identity genes

Back 62

Genes that encode transcription factors that regulate the development of characteristic floral patterns.

Front 63

ABC hypothesis

Back 63

A hypothesis that proposes that three classes of genes direct the formation of the four types of floral organs.