Chapter 12 - Vocabulary Flashcards
Adventitious Root
a root that develops from somewhere other than the root apical meristem that emerges from the seed.
Aerenchyma
tissue composed of loosely packed parenchyma cells with large pores; found in aquatic plants.
Bark
the protective outermost layer of the stems and roots of woody plants; consists of phloem, cork cambium, and cork.
Blade
the flat part of a leaf.
Capillary Action
the tendency of a liquid to rise or fall because of attractive forces between the liquid molecules.
Carbohydrate
a molecule that contains only atoms of carbon, hydrogen, and oxygen in a ratio of 1:2:1.
Casparian Strip
the wax-like strip that runs through the cell wall of an endodermal cell.
Chloroplast
an organelle found in large numbers in many plant cells; the site of photosynthesis within a plant cell.
Companion Cell
a small, nucleated phloem cell that is always associated with a sieve tube element.
Cork Cambium
the meristematic layer in a woody plant that produces cork.
Cotyledon
a structure in the seeds of flowering plants that stores nutrients.
Endodermis
the innermost layer of cells in the cortex of a root.
Fibrous Root System
a root system made up of many small, branching roots.
Guard Cell
one of two kidney-shaped cells that control the opening and closing of a stoma.
Herbaceous
describes plants with stems that do not have wood.
Lateral Root
a smaller root that branches from a larger root.
Meristematic Tissue (Meristem)
tissues consisting of dividing undifferentiated cells (meristematic cells) found in areas of the plant where growth can take place.
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.
Perforation Plate
the perforated end wall of a vessel element.
Petiole
the stalk that attaches the leaf blade to the plant stem.
Photopigment
a pigment that undergoes a physical or chemical change in the presence of light.
Psychotropic
mind-altering.
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.
Root Hair
a microscopic extension of the epidermis cells of the root.
Root Pressure
the osmotic force pushing xylem sap upward in root vascular tissue.
Sieve Cell
a phloem cell with pores in its cell walls; contains all necessary cell organelles.
Sieve Plate
the perforated end wall of a sieve tube element.
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 associates companion cells.
Sink
a plant cell with low concentration of sugars; sugars may be converted to start for storage or used rapidly for energy or as building block of other carbohydrates.
Source
a plant cell with high concentration of sugars and other solutes, such as a lead cell.
Spongy Mesophyll
the layer of loosely packed photosynthetic cells with large air spaces between them under the lower surface of a leaf on a terrestrial plant; part of the mesophyll.
Stoma
a small opening in the epidermis of a plant that allows gas exchange.
Taproot System
a root system composed of a large, thick root; can have smaller lateral roots.
Tracheid
an elongated, tapered xylem cell with thick cell walls containing small pits; tracheids overlap one another at the end to form continuous tubes from root to shoot.
Translocation
long-distance transport of substances through the phloem, particularly glucose.
Transpiration
evaporation of water through the stomata of plant leaves.
Tuberous Root
a lateral root specialized to store carbohydrates.
Turgor
pressure caused by the fluid contents of the central vacuole, which pushes against the wall of a plant cell.
Vascular Bundle
the arrangement of vascular tissue that consists of xylem and phloem.
Vascular Cambium
the meristematic cell layer in vascular tissue.
Vascular Cylinder
the central portion of a root that contains the xylem and the phloem.
Venation
the arrangement of veins within a leaf.
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 tube that run from root to shoot.
Woody
describes plants with stems that contain wood.
