35: Vascular Plant Growth & Development

Question 1

Three tissue systems?

Answer 1

Dermal, vascular, ground tissue

Question 2

What is the outer layer of plants and the waxy coating is called?

Answer 2

Epidermis; cuticle

Question 3

What is the stele?

Answer 3

The stele is the tissue of the vascular system; in roots, it consists of a cylinder while in shoots it consists of bundles

Question 4

What is the pith and cortex?

Answer 4

The pith is internal to the vascular tissue; the cortex is external to the vascular tissue.

Question 5

Which plant cells lack secondary walls and retain the ability to differentiate?

Answer 5

Parenchyma cells; photosynthesis occurs here, some have amyloplasts

Question 6

Which plant cell has a secondary wall, an uneven primary wall, is elongated at maturity, and functions in support?

Answer 6

Collenchyma cells; often found just below the epidermis of younger stems and petioles

Question 7

Which plant cell is dead at functional maturity, is lignified, and has a thick secondary wall?

Answer 7

Scherenchyma cells

Question 8

What are sclereids and fibers?

Answer 8

Sclereids and fibers are specialized entirely for support and strengthening. Sclereids are irregular in shape and have thick, lignified cell walls. Fibers are scherenchyma cells grouped in strands, and are long, tapered, and slender.

Question 9

Tracheids and vessel elements function?

Answer 9

Tracheids and vessel elements are water-conducting cells of the xylem; tubular, elongated cells, dead and lignified at maturity

Question 10

Tracheid vs vessel element? (found where, shape, etc)

Answer 10

Tracheids are found in all vascular plants; vessel elements are found in most angiosperms and some gymnosperms. Tracheids are long, thin cells with tapered ends; vessel elements are shorter, wider, and thinner. They are both hardened with lignin

Question 11

What is a sieve-tube element? What is the function of the companion cell?

Answer 11

Sieve tube elements lack a nucleus, ribosomes, a vacuole, and cytoskeletal elements; the end walls between the elements, sieve tube plates, have pores that facilitate the transport of fluid from cell to cell
A companion cell is connected to the sieve-tube element via plasmodesmata

Question 12

Where are apical meristems found?

Answer 12

Apical meristems are found at root and shoot tips, and enable primary growth, growth in length

Question 13

Two types of lateral meristems? Function?

Answer 13

It enables secondary growth; the vascular cambium adds secondary xylem and phloem; the cork cambium replaces the epidermis with thicker periderm

Question 14

Three types of tissues primary growth gives rise to?

Answer 14

Protoderm, ground meristem, procambium

Question 15

Primary growth of roots? Three zones? Root cap?

Answer 15

Zone of cell division: includes stem cells of the root apical meristems
Zone of elongation: most growth occurs; root cells elongate
Zone of differentiation: the tissues of the root cells begin to differentiate into the protoderm, ground meristem, and the procambium

Question 16

The protoderm gives rise to the

Answer 16

epidermis

Question 17

What does the ground meristem consist of ?

Answer 17

It consists of mostly parenchyma cells in the cortex; the cortex stores sugars and transports water/salts

Question 18

The endodermis is

Answer 18

The endodermis a single layer of cells found at the innermost layer of the cortex adjacent to the vascular cylinder

Question 19

In roots, the procambium gives rise to

Answer 19

vascular cylinder

Question 20

the pericycle

Answer 20

is a layer of cells in the roots that surrounds the vascular cylinder

Question 21

In eudicots, the cross-section of the stele of the root looks like a ______; in monocots, the cross-section appears as a ______.

Answer 21

star; ring

Question 22

apical dominance is

Answer 22

the closer an axillary bud is to an active apical bud, the more inhibited it is

Question 23

In eudicots, the cross-section of the stele of the shoot looks like a ______; in monocots, the cross-section appears as a ______.

Answer 23

ring; scattered

Question 24

What is leaf primordia?

Answer 24

Leaves develop from leaf primordia, projections shaped like cow’s horns that emerge along the sides of the shoot apical meristem

Question 25

Palisade vs spongy mesophyll?

Answer 25

Palisade mesophyll consists of one or more layers of elongated parenchyma cells
Spongy mesophyll consists of more loosely packed cells with air spaces

Question 26

Vascular cambium located in comparison with xylem, pith, phloem, cortex?

Answer 26

It is located outside the pith and primary xylem and to the inside of the primary phloem and cortex

Question 27

What are vascular rays?

Answer 27

vascular rays are radial files of mostly parenchyma cells that connect the secondary xylem and phloem

Question 28

Early/Spring wood vs late/summer wood?

Answer 28

Early/spring wood is usually produced early in season; they have secondary xylem with large diameters and thin cell walls to maximize water transport to leaves
Late/summer wood is produced later, and they are thick-walled and provide more support

Question 29

heartwood and sapwood are?

Answer 29

Older layers of xylem that no longer transport xylem sap are called heartwood; outer layers of the secondary xylem that still transport xylem sap are called sapwood

Question 30

Do all secondary phloem function in sugar transport?

Answer 30

Only the youngest secondary phloem functions in sugar transport

Question 31

What do cork cells deposit before dying?

Answer 31

suberin

Question 32

What tissues do bark include?

Answer 32

Bark includes all the tissues external to the vascular cambium; it includes the secondary phloem and layers of periderm

Question 33

Lenticels are

Answer 33

Letincels are present on the periderm that enable cells to exchange gases in air