Roots and Soils Flashcards
(18 cards)
Radicle
part of the embryo(immature plantlet) that grows and develops the first root
Adventitious Roots
Roots that develop from a stem or leaf not a root.
Fibrous Root System
Root system in which there are many roots of similar size
Root Cap
Mass of parenchyma cells that cover the tip of each root. Used for protection. Secretes a lubricant for moving through soil
Amyloplasts
plastids containing starch grains
Region of Cell Division
Also called the apical meristem. Region of the root close to the cap where cells actively divide.
Apical Meristem
subdivides into three meristematic areas:
1) protoderm-gives rise to outer layer of cells
2) ground meristem: produces parenchyma cells of the cortex
3) procambium-a solid cylinder in the center of the root. produces xylem and phloem
Pith
originates from the ground meristem. usually not present in dicots.
Region of Elongation
Merges with the apical meristem. Cells become longer and wider,
Region of Maturation
cells differentiate here. sometimes called region of differentiation or root-hair zone. many root hairs grow here
Root Hair
increase surface area of root so more water and minerals may be absorbed. The cuticle is typically thinner here.
Cortex
composed of perenchyma cells. lie between epidermis and inner tissues. store food mostly.
Endodermis
single-layered cylinder of compactly arranged cells whose walls are impregnated with suberin.
Casparian Strips
bands made of suberin that are “wrapped” around cells of the endodermis. they keep water out
Passage Cells
Allows water to get through the endodermis to the xylem
Vascular Cylinder
core of tissues inside the endodermis. most cells conduct food or water
Pericycle
cells continue to divide even after maturation. give rise to lateral roots and vascular cambium
Mychorrhizae
mutualistic fungi that aid in plant growth
