POPS Exam 1 - Plant Biology: Key Vocabulary

Vocabulary flashcards covering key terms across cells, tissues, stems, leaves, seeds, roots, and leaf anatomy from the lecture notes.

Determinate growth

Growth with a predetermined end point; growth stops at a specific size or stage.

Indeterminate growth

Growth that can continue indefinitely due to ongoing meristem activity.

Cell theory

All living organisms are composed of cells; cells arise from pre-existing cells; cells are the basic unit of life.

General features of all cells

Cell membrane, cytoplasm with organelles, DNA, and ribosomes.

Eukaryotic cells

Cells with a true nucleus and membrane-bound organelles; linear DNA in a nucleus.

Central vacuole

Large plant cell organelle that stores water and helps maintain turgor pressure.

Chloroplasts

Organelles that carry out photosynthesis; contain chlorophyll.

Cell wall

Rigid layer outside the plasma membrane made of cellulose in plants; provides support.

Meristem

Region of active cell division in plants that produces new tissues.

Apical meristem

Meristem at tips of shoots/roots responsible for primary growth; gives rise to protoderm, ground meristem, and procambium.

Protoderm

Dermal meristem that gives rise to the epidermis.

Ground meristem

Meristem that forms ground tissue (cortex and pith).

Procambium

Meristem that forms primary vascular tissues (xylem and phloem).

Lateral meristem

Meristems responsible for secondary (girth) growth; includes vascular cambium and cork cambium.

Vascular cambium

Lateral meristem producing secondary xylem inward and secondary phloem outward.

Cork cambium

Lateral meristem producing periderm (cork) and phelloderm.

Parenchyma

Thin-walled, living simple tissue; functions in storage, photosynthesis, and wound repair.

Collenchyma

Living simple tissue with unevenly thickened cell walls that provide support.

Sclerenchyma

Rigid, thick-walled, lignified tissue; often dead at maturity; provides mechanical support.

Fibers

Long sclerenchyma cells used for strong supportive tissue.

Sclereids

Short, thick-walled sclerenchyma cells (stone cells) contributing to hardness.

Vascular system

Complex tissue system of xylem and phloem for transport.

Epidermis

Outer protective layer of cells covering plant organs.

Periderm

Protective tissue replacing epidermis in mature stems/roots; includes cork, cork cambium, and phelloderm.

Simple tissue

Tissue made of one cell type (e.g., parenchyma, collenchyma, sclerenchyma).

Complex tissue

Tissue composed of multiple cell types (e.g., xylem, phloem, epidermis).

Stem

Main axis of a plant from which leaves arise; supports, conducts, and stores.

Functions of stem

Support, transport, storage, and sometimes photosynthesis.

Stem morphology

Shape and structure of stems and branching patterns.

Primary growth

Lengthening growth produced by the apical meristem.

Secondary growth

Girth increase produced by lateral meristems (vascular cambium and cork cambium).

Wood and bark formation

Secondary xylem forms wood; periderm forms bark.

Monopodial

Branching pattern with a single dominant main axis.

Sympodial

Branching where the main axis ends and a lateral axis continues.

Petiole

Leaf stalk connecting blade to the stem.

Petiolate

Having a petiole.

Peltate

Leaf attachment where the blade is attached to the stalk from the center of the leaf underside.

Sessile

Leaf lacking a petiole; blade attaches directly to the stem.

Perfoliate

Leaf blade that completely surrounds or clasps the stem.

Phyllotaxy

Pattern of leaf arrangement on a stem.

Alternate

One leaf per node, usually spirally arranged.

Decussate

Opposite leaves in pairs at right angles to the previous pair.

Distichous

Leaves arranged in two vertical rows along the stem.

Whorled

Three or more leaves at a single node.

Simple leaf

A leaf with a single blade, not subdivided into leaflets.

Compound leaf

A leaf with multiple leaflets; leaflets arranged along a rachis.

Palmate

Leaflets radiating from a common point at the leaf base.

Pinnate

Leaflets arranged along a central rachis.

Double compound

A compound leaf with leaflets arranged on secondary rachises (bipinnate).

Midrib

The central axis vein of a leaf.

Parallel venation

Veins run parallel along the leaf (typical of monocots).

Pinnate venation

Main midrib with lateral veins branching along its length.

Palmate venation

Several main veins radiating from a single point at the leaf base.

Reticulate venation

Net-like network of veins.

Percurrent venation

Veins extend from the midrib to the leaf margin.

Leaf margins

The edge of a leaf.

Entire

Smooth leaf margin without teeth or lobes.

Undulate

Wavy leaf margins.

Lobate

Leaf margins with lobes.

Toothed

Leaf margins with tooth-like projections.

Heterophylly

Different leaf forms on the same plant or shoot.

Seeds

Reproductive units containing embryo and stored food, enclosed in a seed coat.

Seed coat

Outer covering of a seed protecting the embryo.

Testa

Outer seed coat layer.

Tegmen

Inner seed coat layer adjacent to the embryo.

Hilum

Scar marking the seed’s point of attachment to the ovule.

Micropyle

Pore in the seed coat through which pollen tube may enter.

Plumule

Embryonic shoot of the seed.

Shoot meristem

Embryonic tissue giving rise to the shoot during germination.

Leaf primordia

Early development of a leaf from the shoot apical meristem.

Radicle

Embryonic root of a seed.

Hypocotyl

Embryonic axis between cotyledons and root; below the cotyledons.

Epicotyl

Embryonic axis above the cotyledons; gives rise to the shoot.

Globular stage

Early spherical stage of embryo development.

Heart stage

Heart-shaped stage of embryo development.

Torpedo stage

Elongated, torpedo-shaped embryo stage.

Seed dispersal

Movement of seeds away from the parent plant by wind, water, animals, etc.

Seed dormancy

A period when seeds do not germinate despite favorable conditions.

Germination

Process by which a seed develops into a seedling.

Epigeous germination

Germination in which cotyledons emerge above ground.

Hypogeous germination

Germination in which cotyledons remain underground.

Tap root

Single main root with lateral branches; common in many dicots.

Fibrous roots

Dense network of many slender roots typically from the stem base.

Root hairs

Tiny epidermal extensions greatly increasing root surface area.

Endodermis

Innermost cortical layer that regulates water and solute movement; contains Casparian strip.

Casparian strip

Suberin-containing band in endodermal cell walls restricting apoplastic flow.

Pericycle

Layer inside the endodermis; origin of lateral roots and potential contributor to secondary growth.

Xylem

Water-conducting tissue composed of tracheids and vessel elements.

Protoxylem

Early-formed xylem with smaller cells that functions during rapid growth.

Metaxylem

Later-formed xylem with larger, more mature cells for long-distance transport.

Phloem

Food-conducting tissue that transports sugars and other solutes.

Sieve cells

Phloem elements in gymnosperms lacking sieve tubes; connected by sieve plates.

Sieve tubes

Phloem elements in angiosperms joined by sieve plates; depend on companion cells.

Sieve plates

End walls with pores between sieve elements allowing flow.

Companion cells

Supportive cells closely associated with sieve elements; provide metabolic support.

Tracheids

Long, thin xylem cells with tapered ends; aid in support and water transport.

Vessel elements

Xylem cells that align to form vessels for efficient water transport.

Vascular rays

Radial files of parenchyma in xylem/phloem for storage and lateral transport.

Heartwood

Older, inactive xylem in the center that provides structural support.

Sapwood

Younger, active xylem near the outside that conducts water.