Roots Flashcards
what are roots responsible for
anchorage to the ground
absorption and conductance of water and minerals
storage
symbioses
what are the 3 tyoes of roots
primary
lateral
adventitious
what is the primary root
first root to emerge from the germinating seed
what is the lateral root
subsequent roots emerging from the primary root
what is the adventitious root
root that emerges from the stem
what are the different root systems
taproot fibrous prop stilt pneumatophores
what are the characteristics of the taproot
primary root is largest root and central to the system
lateral roots emerge from the primary root
where are the oldest lateral roots found
near the base of the root
what plant group does not have taproot systems
monocots
what are characteristics of the fibrous root system
primary root dies shortly after emerging from the seed
lateral roots are all very small and dense
typical in monocots
what are the characteristics of stilt and prop roots
provide extra structure support to the plant
mainly made of adventitious roots
are mainly aerial roots
what are characteristics of pneumatophores
mostly adventitious and aerial roots
specialized in gas exchange
only type of root that can grow upwards
what are the 3 cell types in roots
dermal tissues
ground tissues
vascular tissues
what are the 3 most comon patterns of cellular organization in stems
woody
monocot
dicot
explain monocot herbaceous stems
sylem and phloem both in a ring shape
xylem is on the outside
what is the pith
group of parenchyma cells that form center of vasculature
explain dicot herbaceoys stems
xylem is in the center surrounded by phloem
xylem form a cross shape
explain woody stems
central cross of xylem
surrounding phloem
extra layers of xylem and phloem encircling central vasculature
what is the vascular cambium
what produces additional layers of xylem and phloem in woody stems
what are dermal tissues
layer between external environment and interior of the plant
protects interior of plant from outside
controls flow nd factor from the environment into the plant
what is the epidermis
dermal tissue
single cell layer between outside and gound tissues
cells have no chloroplasts
what is the periderm
dermal tissue found on woody stems
multiple cell layers
often dead cells
what are the specialized structrues of dermal tissue in the root
root cap
mucigel sheath
root hairs
what is the root caps role
detects gravity
lubricates passage of cells through the soil
secretes mucilage
what is mucilage
secretion that lubricates root along the mucigel sheath
what are the characteristics of root hairs
similar to rhizoid
single cell wide
specialized in acquiring water
found only at tips of roots
what are ground tissues
most common cell type
used for support and storage
what is the cortex
ground tissue inthe roots
what composes the ground tissue in roots
parenchyma cells
main functions of ground tissue in roots
water and mineral conductance from surface of the root to the vasculature
stores starches and sugars
what is the endodermis
last layer of the cortex that surrounds the vasculature
what are the characteristics of the endodermis
composed of parenchyma cells
visually distinct from other cortex cells
cell walls imbedded with the casparian strip
what is the casparian strip
hydrophobic compound that limits transfer of water
what are vasculature tissues
specialized in the rapid and efficient transfer of solutions in the plant
what are the types of vascular tissues
xylem
phloem
what is the stele
vascular tissues in the root
what is the pericycle
the outer layer of the stele
what are the root groeth stages
cell division
maturation
elongation
what happens in cell division
mitosis leads to elongation of root
has the root cap
contains meristematic regions
what is meristematic regions
site of creation of new differentiated cells from undifferenciated cells
what are the meristematic regions
protoderm
procambium
ground meristem
apical meristem
what is produced in apical meristem
protoderm
procambium
ground meristem
what is produced in protoderm
dermal tissues
what is produced in procambium
vascular tissues
what is produced in meristem
cortex tissues
what happens in area of elongation
cells elongate
xylem formation beigins
phloem formation matures
what happens in area of maturation
maturation of vasculature
endodermis matures
pericycle forms
root hairs form
what is the important function of roots
they uptake water and minerals into the plant
what are macronutrients
nutrients needed in large quantitities
what are the plants macronutrients
carbon hydrogen oxygen nitrogen phosphorous potassium calcium sulfur
what are micronutrients
nutrients needed in small quantities
what are the plants micronutrients
iron manganese boron molybdenum copper zinc chlorine nickel cobalt sodium silicon
how are soil particles charged
very weakly
how is mater charged
weakly positive
how are most macro and micronutrients charged
positively
what is the cohesion tension theory
force of water is being moved through the plant is greater than the force holding the water to the soil particles
what are the steps for plants to absorb minerals
- minerals must be freed from soil particles
2. minerals must be transported into the plant cell against their concentration gradient
how are minerals freed from soil
H+ molecules released by plant root displace important mineral elements in the soil
CO2 released by the plant roots react with the water in the soil to release H+
how are minerals uptaken in plant
active transport with a transmembrane carrier protein
minerals transported against their electrochemical gradients
what happens to plants growing i soil too acidic or too basic
cant uptake mineras
what happens to plants growing in incorrect pH
results in deficiency symptms and sometimes death
