Chapter 24 - Flowering Plants: Structure and Organization

What is plant growth?

An increase in plant size caused by cell division and cell expansion.

What are meristems?

Regions of actively dividing, undifferentiated plant cells.

What is primary growth?

Growth that increases the length of roots and shoots.

Which meristems are responsible for primary growth?

Apical meristems at root and shoot tips.

What is secondary growth?

Growth that increases the thickness or girth of stems and roots.

Which meristems are responsible for secondary growth?

Lateral meristems, including vascular cambium and cork cambium.

What are the three plant tissue systems?

Dermal, vascular, and ground tissue systems.

What is the function of the dermal tissue system?

It protects the plant and helps regulate water loss and gas exchange.

What is the function of the vascular tissue system?

It transports water, minerals, and sugars throughout the plant.

What is the function of the ground tissue system?

It performs functions such as photosynthesis, storage, and support.

What is the epidermis?

The outer protective cell layer of young plant organs.

What is the cuticle?

A waxy coating on many plant surfaces that reduces water loss.

What are root hairs?

Extensions of root epidermal cells that increase surface area for water and mineral absorption.

What are trichomes?

Hairlike structures on plant surfaces that may protect plants or help reduce water loss.

What are stomata?

Pores that allow gas exchange and water vapor to leave plant tissues.

What are guard cells?

Specialized cells that regulate the opening and closing of stomata.

What is xylem?

Vascular tissue that transports water and dissolved minerals, mainly from roots toward shoots.

What is phloem?

Vascular tissue that transports sugars and other organic nutrients from sources to sinks.

What is parenchyma?

Plant cells with relatively thin walls that commonly function in photosynthesis, storage, and repair.

What is collenchyma?

Living plant cells with unevenly thickened walls that provide flexible support.

What is sclerenchyma?

Plant tissue with thick, often lignified walls that provides strong support.

What are the two common types of sclerenchyma cells?

Fibers and sclereids.

What are tracheids?

Elongated water-conducting cells in xylem.

What are vessel elements?

Xylem cells that join end to end to form vessels for water transport.

Are mature tracheids and vessel elements generally living or nonliving?

They are generally nonliving at maturity.

What are sieve-tube elements?

Phloem cells specialized for transporting sugars.

What are companion cells?

Living phloem cells that help maintain sieve-tube elements and support sugar transport.

What are the two main plant organ systems?

Root system and shoot system.

What organs are part of the root system?

Roots.

What organs are part of the shoot system?

Stems, leaves, flowers, fruits, and buds.

What are the main functions of roots?

Anchoring the plant, absorbing water and minerals, and often storing nutrients.

What are the main functions of stems?

Supporting plant organs and transporting materials between roots and leaves.

What are the main functions of leaves?

Photosynthesis, gas exchange, and regulation of water loss.

What is the root cap?

A protective structure at the root tip that helps protect the growing root.

What occurs in the root zone of cell division?

Cells divide actively near the apical meristem.

What occurs in the root zone of elongation?

Cells lengthen, helping the root grow forward.

What occurs in the root zone of maturation?

Cells differentiate and develop specialized functions; root hairs may form.

What is the cortex of a root?

Ground tissue between the epidermis and the inner vascular region.

What is the endodermis?

The innermost layer of the root cortex that regulates movement of water and dissolved substances into the vascular cylinder.

What is the Casparian strip?

A waterproof band in endodermal cell walls that forces water and solutes to cross cell membranes before entering the vascular cylinder.

What is the pericycle?

A root tissue layer inside the endodermis that can produce lateral roots.

What is the vascular cylinder?

The central root region containing xylem and phloem.

What is a typical monocot root cross section like?

Vascular tissue is commonly arranged in a ring around a central pith.

What is a typical eudicot root cross section like?

Xylem often forms a central star or cross, with phloem between its arms and usually no central pith.

How are vascular bundles arranged in a typical monocot stem?

They are scattered throughout the ground tissue.

How are vascular bundles arranged in a typical eudicot stem?

They are commonly arranged in a ring.

What is the vascular cambium?

A lateral meristem that produces secondary xylem inward and secondary phloem outward.

What is the cork cambium?

A lateral meristem that produces protective tissues associated with the outer covering of woody plants.

What is wood?

Secondary xylem produced by the vascular cambium.

What is bark?

The outer tissues of a woody stem outside the vascular cambium, including secondary phloem and protective tissues.

What is sapwood?

Outer, functional secondary xylem that conducts water.

What is heartwood?

Older inner secondary xylem that no longer conducts water efficiently.

What do annual growth rings often indicate?

Patterns of secondary xylem growth over successive growing seasons.

What is a simple leaf?

A leaf with one undivided blade.

What is a compound leaf?

A leaf with a blade divided into separate leaflets.

What is a petiole?

The stalk connecting a leaf blade to the stem.

What is a leaf sheath?

The leaf base that partly or fully wraps around the stem, common in many monocots.

What are common differences between monocots and eudicots?

Monocots typically have one cotyledon, parallel leaf veins, scattered stem vascular bundles, and fibrous roots; eudicots typically have two cotyledons, netted veins, stem vascular bundles in a ring, and often a taproot.

What is the difference between primary and secondary growth?

Primary growth increases length; secondary growth increases thickness.

How do vascular cambium and cork cambium differ?

Vascular cambium produces secondary xylem and phloem; cork cambium produces protective outer tissues.