Anatomy of Roots, Stems, and Leaves

Fifty question-and-answer flashcards reviewing plant organ anatomy, tissue systems, growth, and functions.

What are the three major tissue systems in plants?

Dermal, vascular, and ground tissue systems.

What is the main role of the dermal tissue system?

To cover and protect the surface of the plant.

What primary function does the vascular tissue system serve?

Facilitates long-distance transport of water, minerals, and sugars.

Which functions are performed by the ground tissue system?

Photosynthesis, storage, and structural support.

Which vascular tissue transports water and minerals from roots to leaves?

Xylem.

Which vascular tissue moves dissolved sugars throughout the plant?

Phloem.

Name the two types of water-conducting cells found in xylem.

Vessel elements and tracheids.

Through what structures do tracheids conduct water between cells?

Pits.

What structures connect sieve tube elements in phloem?

Sieve plates.

Which specialized phloem cells load and unload sugars into sieve tubes?

Companion cells.

What protective layer covers the apical meristem of a root?

Root cap.

Lateral roots originate from which internal root layer?

Pericycle.

What is the zone directly behind the root cap where cells actively divide?

Zone of cell division (apical meristem).

Root hairs are extensions of which root tissue?

Epidermal cells.

Why are root hairs important to the plant?

They increase surface area for water and mineral absorption.

Nodules formed on certain roots house which symbiotic organisms?

Nitrogen-fixing bacteria.

A mutually beneficial association between roots and fungi is called what?

Mycorrhiza.

Which meristem is responsible for primary growth in length of shoots and roots?

Apical meristem.

Which type of growth increases the girth of a plant?

Secondary growth.

Production of wood is the result of which growth type?

Secondary growth.

Vascular bundles arranged in a ring are typical of which flowering-plant group?

Dicots (eudicots).

How are vascular bundles arranged in monocot stems?

Scattered throughout the ground tissue.

Give one example of an underground stem.

Ginger (a rhizome).

Which structure on a stem can give rise to leaves or flowers?

Buds (axillary or apical).

What are the segments of a stem between two nodes called?

Internodes.

What is the waxy layer covering the outer surface of leaves?

Cuticle.

What is the principal function of leaves?

Absorb sunlight for photosynthesis.

Microscopic openings that regulate gas exchange in leaves are called what?

Stomata.

Which pair of cells open and close each stoma?

Guard cells.

In which leaf tissue are chloroplasts most abundant?

Palisade mesophyll (part of the mesophyll).

Which two layers make up the mesophyll of most leaves?

Palisade mesophyll and spongy mesophyll.

What part of the leaf contains xylem and phloem?

The vascular bundle (vein).

Which root layer contains the Casparian strip that regulates water flow into the stele?

Endodermis.

Name two economic uses of roots.

Food storage (e.g., carrots, sweet potatoes) and medicinal compounds (e.g., ginseng).

Name two economic uses of stems.

Sugar production (sugarcane) and construction material (bamboo).

Name two economic uses of leaves.

Vegetables (lettuce, spinach) and beverages (tea).

What term describes plants that undergo only primary growth and remain non-woody?

Herbaceous plants.

What tissue produces secondary xylem and phloem during secondary growth?

Vascular cambium.

Which lateral meristem forms the outer bark of woody plants?

Cork cambium.

The outer protective tissue formed by the cork cambium is called what?

Periderm (bark).

Which type of cell mainly composes the cortex in roots and stems and functions in storage?

Parenchyma cells.

What are sclerenchyma fibers primarily used for in plants?

Structural support.

What is the principal water-conducting cell type in gymnosperms?

Tracheids.

Besides stomatal regulation, what structure on leaves limits excessive water loss?

Cuticle.

Which plant organ typically lacks chloroplasts and does not perform significant photosynthesis?

Roots.

List the three primary functions of stems.

Support, conduction, and sometimes storage or photosynthesis.

What term describes the region between xylem and phloem within a vascular bundle?

(Vascular) cambium.

Which phloem cell type remains alive at maturity—sieve tube elements or vessel elements?

Sieve tube elements.

Why are the end walls of vessel elements perforated?

To allow unimpeded water flow between adjacent vessels.

What growth response allows roots to grow downward into soil?

Positive gravitropism.