Chapter 5 Roots and Soil Flashcards
embryo
(em′bree-oh) an immature sporophyte that develops from a zygote within an ovule or archegonium after fertilization
radicle
(rad′i-kuhl) the part of an embryo in a seed that develops into a root
root cap
(root kap) a thimble-shaped mass of cells at the tip of a growing root; functions primarily in protection
parenchyma
Parenchyma is a type of simple permanent tissue that makes a major part of ground tissues in plants,
amyloplast
(am′uh-loh-plast) a colorless, starch-forming plastid found in roots and involved in gravity perception
region of cell division
(ree′juhn uhv sel′ dih-vizh-uhn) area of actively dividing cells at an apical meristem
apical meristem
apical meristem, region of cells capable of division and growth in the root and shoot tips in plants. Apical meristems give rise to the primary plant body and are responsible for the extension of the roots and shoots.
protoderm
(proh′tuh-durm) the primary meristem that gives rise to the epidermis
ground meristem
(grownd mair′i-stem) meristem that produces all the primary tissues other than the epidermis and stele (e.g., cortex, pith)
procambium
(proh-kam′bee-um) a primary meristematic tissue that differentiates into primary xylem and phloem
region of elongation
(ree′juhn uhv ih-lawng-gey′shuhn) area near an apical meristem in which cells grow in length and width
secondary tissue
(sek′un-der-ee tish′yu) a tissue produced by the vascular cambium or the cork cambium (e.g., virtually all the xylem and phloem in a tree trunk)
region of differentiation
(ree′juhn uhv diff-uhr-en-tee-a′shun) area of maturing cells near an apical meristem
root-hair zone
(root′ hair zohn) area of cells in a root in which protuberances of epidermal cells can be found
root hair
(root hair) a delicate protuberance that is part of an epidermal cell of a root; root hairs occur in a zone behind the growing tip
cortex
(kor′teks) a primary tissue composed mainly of parenchyma; the tissue usually extends between the epidermis and the vascular tissue
endodermis
(en-doh-dur′mis) a single layer of cells surrounding the vascular tissue (stele) in roots and some stems; the cells have Casparian strips
Casparian strip
(kass-pair′ee-un strip) a band of suberin around the radial and transverse walls of an endodermal cell
passage cell
(pas′ij sel) a thin-walled cell of an endodermis
vascular cylinder
(vas′kyu-lur sil′in-der) a core of tissues, including xylem and phloem, that lies to the inside of the endodermis
pericycle
(per′uh-sy-kul) tissue sandwiched between the endodermis and phloem of a root; often only one or two cells wide in transverse section; the site of origin of lateral roots
adventitious
(ad-ven-tish′uss) said of buds developing in internodes or on roots, or of roots developing along stems or on leaves
pneumatophore
(noo-mat′oh-for) spongy root extending above the surface of the water, produced by a plant growing in water; pneumatophores facilitate oxygen absorption
aerial root
(air′ee-uhl root) root formed above the ground
Contractile Roots
A contractile root is a thickened specialized root at the base of a corm, bulb, rosette or other organ which is designed to shrink vertically under conditions of seasonal drought that helps position this plant part at an appropriate level in the ground.
Buttress Roots
Buttress roots are large, wide roots on all sides of a shallowly rooted tree. Typically, they are found in nutrient-poor tropical forest soils that may not be very deep. They prevent the tree from falling over while also gathering more nutrients
Parasitic Roots
Parasitic or Haustorial roots : Plants which depend on plant partially or totally for their food material are known as parasites
haustorium
(pl. haustoria) (haw-stor′ee-um; pl. haw-stor′ee-uh) a protuberance of a fungal hypha or plant organ such as a root that functions as a penetrating and absorbing structure
saprophyte
(sap′roh-fyte) an organism that lacks chlorophyll and obtains nutrients from dead or decaying organic matter
epiphyte
(ep′uh-fyt) an organism that is attached to and grows on another organism without parasitizing it
epiparasite
(ep′uh-par-uh-sahyt) a parasite that feeds upon another parasite
myco-heterotroph
(my-co-het′-ur-oh-trohf) a plant that obtains its carbon from a fungus rather than from photosynthesis
mycorrhiza
(pl. mycorrhizae) (my-kuh-ry′zuh; pl. my-kuh-ry′zee) a symbiotic association between fungal hyphae and a plant root
root nodule
(root nodd′yewl) a small swelling associated with nitrogen-fixing bacteria that invade the roots of leguminous plants and alders
hygroscopic water
(hy-gruh-skop′ik waw′tuhr) water that is chemically bound to soil particles and therefore unavailable to plants
gravitational water
(grav-uh-tay′shun-ul waw′tuhr) water that drains out of the pore spaces of a soil after a rain
capillary water
(kap′i-lair-ee waw′tuhr) water held in the soil against the force of gravity; capillary water is available to plants