Plant Tissues L4

Meristem

Region of actively dividing cells by mitosis considered plant “growth centers.”

Apical meristem

Found at root and shoot tips responsible for primary growth.

Root apical meristem (RAM)

Produces root tissues and allows root elongation.

Shoot apical meristem (SAM)

Produces shoot tissues and allows stem and leaf elongation.

Primary meristems

First meristems derived from RAM and SAM

include protoderm

procambium

Protoderm

Primary meristem that gives rise to the epidermis (dermal tissue system).

Procambium

Primary meristem that gives rise to the vascular tissue system (xylem and phloem).

Ground meristem

Primary meristem that produces the cortex and pith (ground tissue system).

Dermal tissue system

Outer protective covering of plants includes epidermis (may be replaced by periderm).

Epidermis

Protective layer made of unspecialized parenchyma or sclerenchyma secretes cutin to form the cuticle.

Cuticle

Waxy layer of cutin secreted by the epidermis that prevents water loss (desiccation).

Guard cells

Specialized epidermal cells that regulate the opening and closing of stomata for gas exchange.

Stomata

Pores in the epidermis surrounded by guard cells

Trichomes

Hair-like epidermal outgrowths that reduce water loss

Glandular hairs

Specialized trichomes that secrete substances (e.g.

Vascular tissue system

Plant tissue system specialized for transport of water and nutrients.

Xylem

Vascular tissue that transports water and minerals from roots to shoots.

Phloem

Vascular tissue that transports sugars and other organic nutrients.

Stele

The vascular bundle at the center of the root containing xylem and phloem.

Ground tissue system

Plant tissue system that makes up most of the bulk of the plant includes cortex and pith.

Cortex

Ground tissue located between epidermis and vascular tissue functions in storage and support.

Pith

Ground tissue located at the center of the stem functions in storage.

Collenchyma

Living ground tissue cells with thickened corners provide flexible support in young stems and petioles.

Sclerenchyma

Ground tissue cells that are dead at maturity with lignified walls provide rigid support.

Girdling

Process of removing a strip of bark around a tree stem

Bonsai wiring

Practice of wrapping wires around stems to control plant growth and shape.