Leaf Cell

Epidermis

Upper epidermis layer: A single layer of clear cells that allows light to pass through and prevents the loss of water. Lower epidermis layer: A single layer of clear cells that contains stomates and guard cells.

Cuticle

A thin, waxy layer that covers the upper epidermis of the leaf, preventing the loss of water.

Air space

Found in the spongy mesophyll layer and function in the exchange of carbon dioxide and oxygen.

Stomate

Openings (pores) in leaves to exchange photosynthetic gases

Palisade Parenchyma

This layer contains long columnar cells that are packed tightly together. These cells contain chloroplasts and are the main cells carrying out photosynthesis.

phloem

conducts dissolved sugars and is usually confined to the lower part of a vein

xylem

conducts water and dissolved minerals (inorganic nutrients) & is usually located in the upper part of the vein toward the supper epidermis

guard cells

each stoma is bound to two specialized epidermal guard cells -they are responsible for opening and closing the stoma -they are usually the only epidermal cells with chloroplasts Pairs of these cells containing chloroplasts are found on the lower epidermis of the leaf and are responsible for forming stomates. During the day these cells produce sugar by photosynthesis, causing their walls to curve inward and away from each other and creating a space between the cells called a stomate. At night the process is reversed and the stomate closes.

bundle sheath extensions

extend through the mesophyll from the upper epidermis to the lower epidermis -may be composted of parenchyma, collenchyma, or sclerenchyma

bundle sheath

one or more layers of nonvascular cells that surround the larger veins -composed of parenchyma and sclerenchyma cells -they have support columns called bundle sheath extensions

Spongy Parenchyma

the cells are more loosely and irregularly arranged in a layer towards the lower portion -where photosynthesis occurs -primary function is to allow diffusion of gases (particularly CO2) within the leaf

Mesophyll

the photosynthetic group tissue of the leaf -its sandwiched between the upper epidermis and the lower epidermis mesophyll cells (which are parenchyma cells) packed with chloroplasts, are loosely arranged, with many air spaces between them that facilitate gas exchange. these air spaces can account for as much as 70% of the leaf's volume