bot quiz stems and roots

What are the main functions of roots?

Anchorage, absorption of water and minerals, carbohydrate storage, hormone production, and support.

What is the first organ to emerge during germination?

The root.

What is a taproot system?

One main root with smaller lateral roots; common in eudicots and gymnosperms.

What is a fibrous root system?

Many roots with no dominant main root; common in monocots.

What are adventitious roots?

Roots that develop from stems or leaves.

What are feeder roots?

Fine peripheral roots that actively absorb water and minerals.

What are lateral roots?

Roots that branch from a main root.

What are root hairs?

Extensions of epidermal cells that absorb water and minerals.

What are prop roots?

Roots that support tall plants, such as corn.

What are buttress roots?

Roots that support tall tropical trees.

What are aerial roots?

Roots that grow down from branches and provide support, such as in banyan trees.

What are pneumatophores?

Specialized roots that help plants obtain oxygen.

What are contractile roots?

Roots that shorten and pull plants deeper into soil, such as dandelions.

What are haustorial roots?

Roots that penetrate host plants to obtain water and nutrients.

What are epiphytic roots?

Roots that absorb moisture from the air, such as orchid roots.

What is the root cap?

A structure that protects the growing root tip.

What is the root apical meristem?

A region of rapidly dividing cells that produces new root tissues.

What happens in the region of elongation?

Cells elongate, causing the root to grow longer.

What happens in the region of maturation?

Cells differentiate into specialized tissues.

What are amyloplasts?

Starch-containing structures in root cap cells involved in gravity detection.

What is mucigel?

A slippery polysaccharide that protects the root tip as it pushes through soil.

What does the protoderm become?

Epidermis.

What does the ground meristem become in roots?

Ground tissue, including the cortex.

What does the procambium become?

Primary vascular tissues: xylem and phloem.

What is the function of the cortex?

Stores starch and contains air spaces for oxygen diffusion.

What is the endodermis?

The innermost cortex layer that regulates movement into the vascular core.

What is suberin?

A waterproof substance forming a barrier in endodermal cell walls.

What is the pericycle?

A root tissue that produces lateral roots.

What is apoplastic transport?

Movement through cell walls and spaces between cells.

What is symplastic transport?

Movement through cytoplasm connected by plasmodesmata.

What are nitrogen-fixing bacteria?

Bacteria that convert atmospheric nitrogen into nitrogen compounds usable by plants.

What are root nodules?

Swellings on legume roots that contain nitrogen-fixing bacteria.

What are mycorrhizal fungi?

Fungi associated with roots that help absorb minerals, especially phosphate.

What are the main functions of stems?

Support leaves and reproductive structures, transport materials, and sometimes store water or photosynthesize.

What is lignin?

A tough, water-resistant compound that strengthens cell walls and resists decay.

What is a rhizome?

A horizontal underground stem, such as ginger.

What is a stolon or runner?

A horizontal aboveground stem, such as a strawberry runner.

What is a stem tuber?

A swollen underground storage stem, such as a white potato.

What is a corm?

A compact upright underground storage stem, such as gladiolus.

What is a stem tendril?

A thin stem that coils around supports.

What does xylem transport?

Water and minerals, mainly upward.

What does phloem transport?

Sugars from sources to sinks.

What are tracheids?

Narrow xylem conducting cells that are dead at maturity.

What are vessel elements?

Wide xylem conducting cells that are dead at maturity.

What are sieve elements?

Living phloem conducting cells that lack nuclei at maturity.

What are companion cells?

Cells that provide metabolic support and materials to sieve elements.

What is cohesion-tension?

The mechanism by which transpiration pulls water upward through xylem.

What is mass flow in phloem?

Pressure-driven movement of sugar-rich sap from source to sink.

How are vascular bundles arranged in monocot versus dicot stems?

Scattered in monocots; arranged in a ring in dicots.

What does vascular cambium produce?

Secondary xylem toward the inside and secondary phloem toward the outside.

What does cork cambium produce?

Cork and parenchyma that form the periderm.

What are lenticels?

Openings in cork-covered stems that allow gas exchange.

What is heartwood?

Older, nonfunctional inner wood, often darker.

What is dendrochronology?

The study of tree rings.

What is the difference between early wood and late wood?

Early wood is less dense; late wood is denser.

What is primary versus secondary growth?

Primary growth increases length; secondary growth increases thickness.