Plant Structures and Their Functions

Primary plant body

Herbaceous parts derived from apical meristems.

Secondary plant body

Woody parts developed from secondary meristems.

Parenchyma

Metabolically active cells with thin walls.

Collenchyma

Cells providing plastic support, allowing bending.

Sclerenchyma

Thick-walled cells providing structural support.

Tracheids

Dead cells in vascular plants for water conduction.

Vessel Elements

Dead cells in angiosperms for efficient fluid transport.

Phyllotaxy

Arrangement of leaves on a stem to minimize shading.

Internodes

Regions between nodes on a plant stem.

Axillary bud

Dormant shoot that can develop into a branch or flower.

Guard cells

Cells regulating stomatal openings for gas exchange.

Cortex

Interior tissue composed of parenchyma and collenchyma.

Phloem

Vascular tissue transporting sugars and minerals.

Sieve cells

First type of phloem cell to evolve.

Sieve tube members

Phloem cells with sieve plates, found in angiosperms.

Xylem

Transports water and minerals from roots.

Vessel elements

Short xylem cells with perforations for fast water transport.

Pith

Ground tissue at the center of the stem.

Petiole

Stalk that connects leaf blade to stem.

Leaf flutter

Movement that cools leaves and mixes air.

Abscission zone

Region where leaves detach from stems.

Sessile leaf

Leaf without a petiole, attached directly to stem.

Petiolate leaf

Leaf with a petiole connecting to stem.

Leaf blade

Flat part of the leaf, also called lamina.

Compound leaves

Leaves divided into smaller sections called leaflets.

Pinnately compound leaves

Leaves with leaflets arranged along a central axis.

Palmately compound leaves

Leaves with leaflets radiating from a single point.

Mid-rib

Central vein running down the leaf.

Adaxial side

Leaf side facing the sun.

Abaxial side

Leaf side facing the ground, more stomata present.

Epidermis

Outer layer of leaf, protects against water loss.

Stomata

Pores for gas exchange, surrounded by guard cells.

Mesophyll

Tissue between epidermis, site of photosynthesis.

Palisade mesophyll

Upper leaf layer, where most photosynthesis occurs.

Spongy mesophyll

Lower leaf layer, facilitates gas diffusion.

Succulent leaves

Thick leaves reducing water loss, perform CAM photosynthesis.

Sclerophyllous leaves

Leaves with sclerenchyma cells, typical in evergreen plants.

Trap leaves

Leaves that capture insects, can be active or passive.

Roots

Anchor plants, absorb water and minerals.

Taproot

Main root in dicots, develops from radicle.

Fibrous root system

Root system in monocots, lacks a main taproot.

Root cap

Protective tip of the root, produces mucigel.

Apical meristem

Region of cell division at root tip.

Endodermis

Inner root layer with Casparian strips regulating water flow.

Mycorrhizae

Fungal associations enhancing nutrient absorption in roots.

Secondary growth

Growth allowing woody plants to increase leaf production.