Chapter 23 Vocabulary

vascular tissue

Plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body.

xylem

Plant tissue that transports water and minerals from the roots to the leaves / flowers

taproot

primary root found in some plants that grows longer and thicker than other roots

leaf

the main organ of photosynthesis and transpiration in higher plants

petiole

the slender stem that supports the blade of a leaf

vascular cambium

A continuous cylinder of meristematic cells surrounding the xylem and pith that produces secondary xylem and phloem.

cork cambium

A cylinder of meristematic tissue in plants that produces cork cells to replace the epidermis during secondary growth

collenchyma

A flexible plant cell type that occurs in strands or cylinders that support young parts of the plant without restraining growth

node

A point along the stem of a plant at which leaves are attached.

internode

A segment of a plant stem between the points where leaves are attached.

stem

A vascular plant organ consisting of an alternating system of nodes and internodes that support the leaves and reproductive structures.

tracheid

A water-conducting and supportive element of xylem composed of long, thin cells with tapered ends and walls hardened with lignin.

root

An organ in vascular plants that anchors the plant and enables it to absorb water and minerals from the soil.

blade

Broad, flat portion of a leaf.

differentiation

Cells develop different forms adapted to specific functions

parenchyma

Fundamental tissue composed of thin-walled living cells that function in photosynthesis and storage.

cortex

Ground tissue that is between the vascular tissue and dermal tissue in a root or dicot stem.

primary growth

Growth produced by apical meristems, which lengthen stems and roots.

secondary growth

Growth produced by lateral meristems, which thickens the roots and shoots of woody plants.

phloem

Living vascular tissue that carries sugar and organic substances throughout a plant

leaf vein

Located on the leaf. Contains xylem and phloem tubes.

spongy mesophyll

Loosely arranged mesophyll cells with large spaces to hold carbon dioxide

transpiration

Loss of water from a plant through its leaves

heartwood

Older xylem near the center of a woody stem that no longer conducts water

palisade mesophyll

One or more layers of elongated photosynthetic cells on the upper part of a leaf; also called palisade parenchyma.

sapwood

Outer layers of secondary xylem that still transport xylem sap.

companion cell

Phloem cells. Surround sieve tube elements to aid transport.

root hair

Structures that develop from epidermal cells and are the plant's major route of entry for water and mineral nutrients. Each consists of a single cell that is derived from the epidermis of the root.

mesophyll

The ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis.

endodermis

The innermost layer of the cortex in plant roots; a cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder.

dermal tissue

The protective covering of plants; generally a single layer of tightly packed epidermal cells covering young plant organs formed by primary growth.

vessel element

Wide, shorter, and less tapered. Are water-conducting cells.

root cap

a structure that covers the tip of a root, protecting the root from injury

guard cell

cells that control the opening and closing of stomata

vascular cylinder

central region of a root that includes the vascular tissue-xylem and phloem

vascular bundle

clusters of xylem and phloem tissue in stems

sieve tube element

found in phloem; stacked end to end; have holes so materials can get in and out of the phloem

stoma

openings in the leaf of a plant that allow for gas exchange and transpiration

pith

parenchyma cells in the center of a dicot stem

fibrous root

part of a root system in which roots branch to such an extent that no single root grows larger than the rest

bud

plant structure containing undeveloped tissue that can produce new stems and leaves

meristematic tissue

plant tissue found only in the tips of shoots and roots; responsible for plant growth

sclerenchyma

type of ground-tissue cell with an extremely thick, rigid cell wall that makes ground tissue tough and strong

casparian strip

waterproof strip that surrounds plant endodermis cells