Flashcards in PLANT ROOT Deck (12):
Ring of the root outside of the endodermis composed of many parenchyma cells, that store food (especially in the form of starch).
Very outer edge of the root (outer skin).
This area covers the entire root, except for the area immediately around the root cap.
Three root zones
1.) Zone of maturation
2.)Zone of elongation
3.)Zone of cell division
Zone of Maturation
(Zone of differentiation)
Where meristematic root cells differentiate into a mature form and function.
It is here that they specialize into of the following plant tissues~dermal,ground, or vascular tissues.
Zone of Elongation
In this region, cells grow by elongation.
Cells work like bio-hydraulic pumps (empty vacuoles fill with water, creating hydraulic pressure inside the cells making the root tip move downward) to force the roots through the soil.
Zone of Cell Division
Named after the root apical meristem, cells undergo rapid mitotic division and are either pushed up to the zone of elongation or down toward the root tip.
Those cells that get squashed down, line up with cells in front whilst new cells are produced behind.
This phenomena creates columella cells (rectangular cells that line up in columns), which in turn make up the root cap.
Protects the root apical meristem while the root moves through the soil.
One way it protects is through the production of lubricating mucilage
Cells here contain, Statoliths: Heavy specialized organelles that sink to the bottom of the cell (in essence act as weights) helping roots detect gravity. This phenomenon also triggers the cellular membranes of this area to produce auxin and therefore, Statoliths, are partially responsible for the downward direction of root growth
Outer cells of root tips are eventually sloughed off and replaced by new ones. Sloughed cells supplement the plants' amino acid/sugar exudate content attracting microbes necessary for nutrient uptake into the rhizosphere.
With a texture such as gel, the mucilage is particularly apt. at seeping into minuscule soil particles/crevices and softening them before actual contact with the root tips.
Has a great influence on the uptake of metal nutrients. Phosphorus, zinc, iron, and magnesium all diffuse in through the mucilage.
Nutrient uptake is dictated by the concoction of chemicals that a plant gives off into the rhizosphere through mucilage.
Area inside of the endodermis.
Important to note that different plant species have different kinds of vascular bundles.
A thin layer of cells,just inside the endodermis (outermost layer of the stele), that retains the ability to grow.
Generally dedicated toward lateral growth (widening) sometimes new roots or branches can develop from this region.
This growth is responsible for lateral roots, that grow out through the casparian strip, through the cortex, and into the soil. (Usually developing root hairs as well)
As a whole new (3 part) root tangent is made, the pericycle will go back to increasing girth.
A plant tissue located between the xylem and the phloem in the stems and roots of plants.
It is the source of both secondary xylem growth inwards towards the pith, and secondary phloem growth outwards to the bark.
Responsible for creating new xylem or phloem cells, as directed from intercellular messages.
Also works with the pericycle in the creation of new roots and shoots.