Ch 7 Flashcards
Radicle
the main root of a seed; it is the direct continuation of the embryonic stem
Taproot system with lateral roots
fleshy roots that are the plants main site of carbohydrate storage during the winter; fine lateral roots growing but removed before they are sold; carrots, beets, turnips
Fibrous root system
many similarly sized roots in most monocots and some eudicots
Adventitious roots
roots that form on leaves, nodes or cuttings rather than on another root; an organ that forms in an unusual place; increase the absorptive and transport capacity of the root system
Root cap
a thick layer of cells that protects the root apical meristem
Mucigel
a complex polysaccharide which lubricates passage of the root through the soil secreted by the dictyosomes of root cap cells
Apical meristem
regular files of cells that originate in the meristem and extend into regions of mature root tissues
Quiescent center
mitotically inactive central region
Zone of elongation
just behind the root cap and root apical meristem only a few mm long within which the cells undergo division and expansion
Protoderm
any immature epidermal cell
Protoxylem
the part of the primary xylem that differentiates early, while adjacent cells are still elongating
Protophloem
the part of the primary phloem that differentiates early, while adjacent cells are still elongating
Ground tissue
The tissue of a plant other than the epidermis, periderm, and vascular tissues, consisting primarily of collenchyma, parenchyma, and sclerenchyma. Cortex and pith are types of ground tissue
Zone of Maturation/ root hair
root hairs grow outward, which increases the absorption of water and minerals
Epidermis with root hairs
epidermal cells extend out as narrow trichomes; root hairs form only part of the root that is not elongating, otherwise they would be shorn off
Epidermis with Casparian strips
layer of impermeable lignin and suberin in the walls of endodermal cells, preventing diffusion of material through that portion of the wall
Cortex
primary tissue located between the epidermis and the phloem
Metaxylem
the part of the primary xylem that differentiates late, after adjacent cells have completed their elongation
Metaphloem
the part of the primary phloem that differentiates late, after adjacent cells have completed their elongation
Pericycle
an irregular band of cells in the root, located between the endodermis and the vascular tissue
Mature root
continued maturation of the endodermis is the formation of a watertight sheath around vascular tissues to keep water in; underlying cortex and epidermis often die and are shed from the root
Xylem
the water and mineral conducting portion of vascular tissues. containing either tracheids or vessel elements or both
Phloem
involved in conducting sugars and other organic compounds along with some water and minerals
Lateral roots
initiated by cell divisions in the pericycle