Plant Tissue Systems

Lower epidermis

Upper epidermis

Palisade layer

Spongy layer

Cuticle

A waxy coating on the surface of stems and leaves that helps retain water

Stomata

A microscopic pore surrounded by guard cells in the epidermis of a leaf. When they are open, CO2 enters a leaf and H2O and O2 exit. A plant conserves water when these are closed.

Guard cells

A specialized epidermal cell in plants that regulates the size of a stoma, allowing gas exchange between the surrounding air and the photosynthetic cells in the leaf

Vein

A vascular bundle in a leaf, composed of xylem and phloem.

Air space

Xylem

The nonliving portion of a plant's vascular system that provides support and conveys water and minerals from the roots to the rest of the plant.

Phloem

The portion of a plant's vascular tissue system that transports sugars and other organic nutrients from leaves or storage tissues to other parts of the plant.

Chloroplast

Mesophyll

Leaf cells specialized for photosynthesis; a leaf's ground tissue system.