AP Biology: Plats, Chapter 11 - The Leaf

Cuticle

A layer coating the epidermis of higher plants and consisting of lipid and hydrocarbon polymers impregnated with wax; synthesized by the epidermal cells.

Cuticle

A layer of lipid polymer impregnated with waxes that is present on the outer surfaces of the primary organs of all vascular land plants.

Stomata

A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant.

Stomata

A pore, found in the epidermis of leaves, stems, and other organs, that is used to control gas exchange; bordered by a pair of guard cells that are responsible for regulating the size of the opening.

Bundle Sheath

A sheath around a vascular bundle that consists of a layer of parenchyma; forms a protective covering on leaf veins.

Bundle Sheath

A sheath which surrounds the vascular bundle so that no vascular tissues are exposed to intercellular space and no air bubbles can enter to impede water movement.

Epidermis

A single layer of cells that covers the leaves, flowers, roots and stems of plants; functions to protect against water loss, regulates gas exchange, secretes metabolic compounds, and absorbs water and mineral nutrients

Epidermis

A single layer of cells, coated in cuticle, which form a boundary between the plant and the external environment; provide mechanical strength and protection to the plant.

Vascular Bundle

A strand of conducting tissue extending lengthwise through the stems and roots of higher plants; consists of xylem and phloem.

Vascular Bundle

A strandlike part of the plant vascular system containing xylem and phloem.

Spongy Mesophyll

A system of loosely and irregularly arranged parenchymal cells with numerous intercellular spaces found near the lower surface in well-differentiated broad leaves.

Palisade Mesophyll

A tissue system of the chlorenchyma in well-differentiated broad leaves composed of closely spaced palisade cells oriented parallel to one another, but with their long axes perpendicular to the surface of the blade.

Vascular Bundle

A unit stand consisting of xylem, which conducts water and dissolved mineral substances from the soil to the leaves, and phloem, which conducts dissolved foods, especially sugars, from the leaves to the storage tissues of the stem and root.

Vascular Bundle

A unit strand of the vascular system in stems and leaves of higher plants consisting essentially of xylem and phloem.

Cuticle

A water permeability barrier that prevents evaporation of water from the epidermal surface, and also prevents external water and solutes from entering the tissues.

Cuticle

A waxy layer that covers the outermost tissue layer of a plant; secreted by the epidermis and helps prevent water loss and infection by parasites.

Leaf

An organ of a vascular plant and is the principal lateral appendage of the stem; organized to maximize sugar production and minimize water loss.

Stomata

Any of the minute pores in the epidermis of the leaf or stem of a plant, forming a slit of variable width that allows movement of gases in and out of the intercellular spaces.

Spongy Mesophyll

Consists of less tightly packed cells that are surrounded by air spaces, which allow for the exchange of oxygen, carbon dioxide, and water vapor.

Guard Cells

Either of a pair of crescent-shaped cells that flank each plant pore and control its opening and closing by means of turgidity.

Spongy Mesophyll

Irregularly shaped cells that have many intercellular spaces that allow the passage of gases, such as the carbon dioxide needed for photosynthesis.

Spongy Mesophyll

Loose tissue beneath the palisade layer of a leaf; has many air spaces between its cells so water can find its way to the stomata; connects to the outside of the leaf through the stomata.

Spongy Mesophyll

Loosely packed, irregularly shaped cells with spaces around them located below the palisade mesophyll

Guard Cells

Modified epidermal cells which mediate opening and closure of the stomatal pore by changes in the turgor pressure.

Guard Cells

One of a pair of crescent-shaped cells that surround a pore (stoma) in the epidermis; changes in the turgidity of the cells cause the opening and closing of the stoma.

Guard Cells

One of the paired cells that control the opening and closing of a stoma of a leaf; when not swollen by turgid pressure, move closer together, allowing the plant to conserve water.

Guard Cells

One of the paired cells that control the opening and closing of a stoma of a leaf; when swollen with water, pull apart from each other, opening the stoma to allow the escape of water vapor and the exchange of gases.

Guard Cells

One of the paired epidermal cells that control the opening and closing of a stoma in plant tissue.

Bundle Sheath

Photosynthetic cells arranged into tightly packed sheaths around the veins of a leaf; form a protective covering on leaf veins, and consist of one or more cell layers.

Palisade Mesophyll

Plant cells located within the mesophyll in leaves, right below the upper epidermis and cuticle; absorb a major portion of the light energy used by the leaf.

Palisade Mesophyll

Plant cells located within the mesophyll in leaves, right below the upper epidermis and cuticle; vertically elongated, a different shape from the spongy mesophyll cells beneath them in the leaf.

Palisade Mesophyll

Plant cells which contain the largest number of chloroplasts per cell, making them the primary site of photosynthesis and converting the energy in light to the chemical energy of carbohydrates.

Stomata

Pore-like openings in leaves that allow gases (CO2 and O2) and water to diffuse in and out of the leaves.

Guard Cells

Specialized cells in the epidermis of leaves, stems and other organs that are used to control gas exchange; produced in pairs with a gap between them that forms a stomatal pore.

Stomatal Crypts

Stomata located in sunken cavities where they are sheltered from drying effects of air currents.

Leaf

Structures covered in cuticle to prevent water; normally extensively vascularised and typically have networks of vascular bundles containing xylem, which supplies water for photosynthesis, and phloem, which transports the sugars produced by photosynthesis.

Stomatal Crypts

Sunken cavities found in xerophytes below the leaf surface that minimize dryness; further minimize exposure of stomate to air.

Stomatal Crypts

Sunken cavitites below leaf surface, sheltered from drying effects of air currents; further minimize exposure of stomate to air.

Leaf

Terminal outgrowths of plant foliage, usually flat green blades that conduct the plants' photosynthesis.

Epidermis

The outermost layer of cells in leaves and the young parts of plants.

Leaf

The primary photosynthetic organs of cells maximising the surface area directly exposed to light and enabling the light to penetrate the tissues and reach the chloroplasts, thus promoting photosynthesis.

Leaf

The principal photosynthetic organ of vascular plants, which typically consists of a flattened lamina joined to the stem by a stalk or petiole, at which junction an axillary bud can be found.

Cuticle

The protecting film covering the epidermis of leaves, young shoots and other aerial plant organs without periderm; synthesized by the epidermal cells.

Cuticle

The protective layer, containing cutin, that covers the epidermis of higher plants.

Spongy Mesophyll

The tissue that is made up of loosely arranged parenchyma cells that contain chloroplasts and are surrounded by air spaces that promote the diffusion of oxygen, carbon dioxide, and water throughout the leaf