Primary Growth and Development (Video)

Vocabulary flashcards covering plant growth, meristems, tissues, roots, stems, leaves, and hormones from the lecture notes.

Apical bud

Bud at the tip of a stem containing meristematic tissue that drives primary growth.

Node

Point on a stem where leaves and axillary buds attach.

Internode

Stem segment between two consecutive nodes.

Blade

The broad, flat part of a leaf.

Leaf

The photosynthetic organ of a plant, typically with blade and petiole.

Petiole

Stalk that attaches the leaf blade to the stem.

Axillary bud

Bud located in the axil between a leaf and stem; can develop into a branch or shoot.

Stem

The above-ground axis that supports leaves and reproductive structures.

Taproot

Main vertical root that can give rise to lateral roots and enable deep water access.

Lateral branch

Branch that grows from the stem.

Root system

All the underground roots of a plant.

Flower

Reproductive structure produced by the shoot; often forms at the tip of branches.

Shoot system

The above-ground parts of a plant, including stems and leaves.

Root system

The underground part consisting of roots.

Stem tuber

A modified stem used to store food underground.

Bulb

A short, flattened stem bearing fleshy, food-storing leaves.

Rhizome

An underground, horizontal stem.

Totipotent

Capability of plant cells to develop into any cell type; basis for tissue culture.

Meristem

Region of continuous cell division; three types: apical, lateral, intercalary.

Apical meristem

Meristem at the tip of shoots or roots; drives primary growth and gives rise to primary meristems.

Lateral meristem

Meristems that cause widening; includes vascular cambium and cork cambium.

Intercalary meristem

Meristem located between nodes; common in grasses.

Primary growth

Growth that lengthens the plant via elongation at apical meristems.

Secondary growth

Growth that widens the plant via lateral meristems (vascular and cork cambia).

Procambium

Primary meristem that forms vascular tissue (xylem and phloem).

Ground meristem

Primary meristem that forms ground tissue (cortex and pith).

Protoderm

Primary meristem that forms the epidermis.

Cork cambium

Lateral meristem that produces cork and phelloderm (part of bark).

Cork

Outer protective tissue produced by cork cambium.

Phelloderm

Inner bark tissue produced by cork cambium.

Epidermis

Outer dermal tissue derived from protoderm.

Pith

Central parenchymatous tissue in stems; stores nutrients.

Cortex

Tissue between epidermis and vascular tissue; stores nutrients and provides support.

Vascular cambium

Lateral meristem producing secondary xylem and secondary phloem.

Fascicular cambium

Cambial tissue within vascular bundles contributing to secondary growth.

Interfascicular cambium

Cambial tissue between vascular bundles contributing to secondary growth.

Pericycle

Layer of cells just inside the endodermis from which lateral roots arise.

Endodermis

Layer surrounding vascular tissue regulating movement into the vascular cylinder.

Root cap

Protects the root apical meristem as the root grows; cells are replaced by the meristem.

Root apical meristem

Meristem at the tip of a root responsible for elongation and differentiation.

Lateral roots

New roots that develop from the pericycle to increase root branching.

Auxin

Class of hormones produced in the shoot apical meristem and young leaves; regulates growth and apical dominance; promotes cell wall loosening and elongation.

Cytokinin

Hormone produced in the root apical meristem and developing fruits; promotes cell division and directs nutrient flow.

Gibberellin

Hormone produced in the shoot apical meristem and embryo; works with auxin to promote cell division in internodes; promotes phloem differentiation and seed dormancy.

Expansins

Proteins that loosen the cellulose network in the cell wall to allow cell expansion.

Turgor pressure

Hydrostatic pressure inside plant cells that drives cell expansion.

Apical dominance

Phenomenon where the shoot apex inhibits growth of axillary buds, keeping growth upward.

Callus

Undifferentiated plant tissue formed in culture that can differentiate into shoots or roots under the right hormone balance.

Tissue culture

Growing plant cells or tissues in vitro on nutrient media under controlled conditions.

Balanced auxin-to-cytokinin ratio

A hormone balance that determines whether cultures form shoots, roots, or remain as undifferentiated callus.

Leaf primordia

Early leaf tissue produced by the shoot apical meristem; contains primary meristematic tissue and procambium for vein formation.

Leaf arrangement

Pattern of leaf deposition on the stem, determined by leaf primordia patterning.

Shoot apical meristem

Apex of the shoot that produces new leaves and stems.