Grade 11 biology - Plant Anatomy, Growth and Function

Carbohydrate

A molecule that contains only atoms of carbon, hydrogen, and oxygen in a ratio of 1:2 :1

Cotyledon

A structure in the seeds of flowering plants that store nutrients

Chloroplast

An organelle found in large numbers in many plant cells; the site of photosynthesis within a plant cell

Photopigment

A pigment that undergoes a physical or chemical change in the presence of light

Blade

The flat part of a leaf

Petiole

The stalk that attaches the leaf blade to the plant stem

Venation

The arrangement of Viens within a leaf

Mesophyll

The photosynthetic middle layer of cells in the leaf of a terrestrial plant

Palisade mesophyll

The layer of elongated photosynthetic cells arranged in columns under the upper surface of a leaf on a terrestrial plant; part of the mesophyll

Spongy mesophyll

The layer of loosely packed photosynthetic cells with large air spaces between them under the lower surface of a lead on a terrestrial plant; plant of the mesophyll

Stoma

A small opening in the epidermis of a plant that allows gas exchange

Guard cell

One of two kidney-shaped cells that control the opening and closing of a stoma

Aerenchmya

Tissue composed of loosely packed parenchyma cells with large pores; found in aquatic plants

Psychotropic

Mind-altering

Herbaceous

Describes plants with stems that do not have wood

Woody

Describes plants with stems that contain wood

Vascular bundle

The arrangement of vascular tissue that consists of xylem and phloem

Vascular cambium

The meristematic cell layer in vascular tissue

Bark

The protective outermost layer of the stems and roots of woods plants: consists of phloem, cork cambium, and cork

Cork cambium

The meristematic layer in a woody plant that produces cork

Tracheid

An elongated, tapered xylem cell with thick cell walls containing small pits; tracheids overlap one another at the ends to form continuous tubes from root to shoot

Vessel element

A shorter, blunt-ended xylem cell with thick cell walls containing small pits; vessel elements are stacked end to end to form vessel tubes that run from root to shoot

Perforation plate

The perforated end wall of a vessel element

Sieve cell

A phloem cell with pores in its cell walls; contains all necessary cell organelles

Sieve tube element

A phloem cell with pores in its side cell walls and a sieve plate at the end walls; sieve tube elements lack organelles and depend on associated companion cells

Sieve plate

The perforated end wall of sieve tube element

Companion cell

A small, nucleated phloem cell that is always associated with a sieve tube element

Taproot system

A root system composed of a large, thick root; can have smaller lateral roots

Lateral root

A smaller root that branches from a larger root

Root hair

A microscopic extension of the epidermal cells of the root

Fibrous root system

A root system made up of many small, branching roots

Root cap

The mass of cells that form a protective covering for the meristem at the root tip

Root cortex

A region of parenchyma cells under the epidermis of a root

Endodermis

The innermost layer of cells on the cortex of a root

Casparian strip

The wax-like strip that runs through the cell wall of an endodermal cell

Vascular cylinder

The central portion of a root that contains the xylem and the phloem

Tuberous root

A lateral root specialized to store carbohydrates

Adventitous root

A root that develops from somewhere other than the root apocalypse meristem that emerges from the seed

Root pressure

The osmotic force pushing xylem sap upward in root vascular tissue

Capillary action

The tendency of a liquid to rise or fall because of attractive forces between the liquid molecules

Transpiration

Evaporation of water through the stomata of plant leaves

Turgor

Pressure caused by the fluid contents of the central vacuole, which pushes against the wall of a plant cell

Source

a plant cell with a high concentration of sugars and other solutes, such as a leaf cell

Sink

A plant cell with a low concentration of sugars; sugars may be converted to starch for storage or used rapidly for energy or as building blocks of other carbohydrates

Translocation

Long-distance transport of substances through the phloem particularly glucose

Dermal tissues

-two tissue types: epidermis and periderm

-outermost cell layers

-often have thicker cell walls

-covered with a waxy cuticle

Meristematic tissue (meristem)

Tissue consisting of dividing undifferentiated cells (meristematic cells) found in areas of the plant where growth can take place

Vascular tissues

-Two tissue types : xylem and phloem

-Xylem—thick-walled cells, dead at maturity

-phloem—thin-walled cells, living at maturity

Ground tissues

-three tissue types:

-parenchyma—thin walled cells, living at maturity

-collenchyma—thickwalled cells, living at maturity

-sclerenchyna—cells with lignin in their cell walls, dead at maturity

Role of dermal tissues

-protect against injury herbivores, disease, and water loss

Role of vascular tissues

-transport water and nutrients

-support the plant body

Role of ground tissues

-perform cellular processes to support growth and development(parenchyma and collenchyma)

-store carbohydrate, especially starch (parenchyma)

-support and protect plant body (collenchyma and sclerenchyna)