Quiz 2 Flashcards
Early plants with shoots had
No vascular tissue or roots
Had rhizoids
first type of roots were
adventitious: arise from shoots
2 types of roots
- adventitious
2. roots from other roots
what plants have roots from other roots
seed plants
what is the first root of seed plants>
radicle
seed plant roots contain
radicle, cotyledons, hypocotyl, and epicotyl
what is a cotyledon
in seed plant–> seed leaves
What is a hypocotyl
connects roots to shoots in seed plants
axis that connects cotyledons to the root
epicotyl
in seed plants
- above the hypocotyl
- young shoot
radicles die in what plants>
palms and grasses
monocots have what type of roots?
adventitious only
what is the function of a root
- water/nutrient uptake
- anchoring
- storage
- photosynthesis (some)
Epiphytes are
plants that grow on other plants
- does not parasitize them
- does not root in the soil
name the root zones
- apical meristem (RAM)/zone of cell division
- zone of elongation (growth occurs)
- zone of differentiation (maturation where stele matures and trichomes elongate)
What did roots evolve from?
rhizomes
Root apical meristem (RAM)
zone of cell division-apical meristem where primary root growth occurs
- RAM is bifacial
- cells formed to outside produce root cap
- cells formed to inside produce plant body
Root cap
covers and protects the root tip
protects RAM
can sense gravity: cells in columella have statoliths
quiescent center
light colored cells in RAM
no division
zone of differentiation
root hairs are trichomes that increase surface area for water/nutrient absorption
-only certain epidermal cells produce root hairs
Periderm
- replaces epidermis
- to the inside is cork parenchyma for photosynthesis and storage
- cork is to the outside and is dead at maturity. suberin in cw
- cork cambia is replaced and new cork cambia form in older secondary phloem (light and dark bands in bark)
- lenticels
Lenticels
openings in periderm for gas exchange
primary root stele
no pith present in most roots
- epidermis, cortex (storage parenchyma), endodermis, pericycle, vascular cylinder
- xylem and phloem mature from outside to in
- stele can be diarch, triarch, tetrarch, pentarch, or polyarch(more than 5)
apoplastic movement
water and nutrients move around the cells along the cell wall
symplastic movement
water and nutrients move through the symplasm. (from one cytoplasm to another, connected by plasmodesmata)
casparian strip
lignin and suberin on radial and transverse walls that prevent water in or out
-forces symplastic movement of water and solutes (moves radially)
Pericycle and 3 fx
- produces periderm and is located between endodermis and phloem
1. produces branch roots endogenously (arises from the inside) and laterally (side/branch)
2. made up of parts of the vascular cambium (pericycle + F.C. = new vascular cambium)
3. produces the entire cork cambium in roots
vascular cambium
- cells in procambium and pericycle make periclinal divisions
- inner layer of cells is v.c.
- outer layer is retained as pericycle
- v.c. is continuous around the primary xylem and below the primary phloem (fascicular cambium)
Root types
- tap root
- fibrous root
- prop roots
- aerial roots
tap root
develops from the radicle
ex: carrots, dandelions, gymnosperms. woody roots and herbaceous stems
fibrous roots
- grasses
- all adventitious roots and usually no tap roots
- many fine roots
prop roots
- produces roots from shoots
- adventitious
- no secondary growth
- ex: corn
aerial roots
- prop roots are a type of aerial root
- usually exposed all the time
- mangroves: pneumatophores stick out of surface of water, loaded with air canals
some storage root
- woody–> parenchyma in wood
- others have a lot of parenchyma/strange secondary growth
Respiration steps (4)
- glycolysis (not aerobic)
- Formation of Acetyl CoA (in mt)
- Krebs cycle (citric acid cycle) in mt
- electron transport chain in mt
ATP synthase
- part of ETC in inner mem
- protons move passively
- energy from the diffusion of protons
FADH2 complex II and NADH complex I vs Quinone complex I and II
FADH2 complex II and NADH complex I have “higher” (more negative) redox potential than Quinone complex I / II
absorption of light
blue and red light absorbed by chloroplasts in chlorenchyma located in mesophyll layer of cell
Carotenoids
good at quenching (getting rid of energy) and produces heat
why are chl concentrations higher in shade leaves?
to catch more photons because the chances of hitting shade leaves in much lower than sun leaves
resonance transfer
- molecules excited and passes excitation to a near molecule
- transfer from one pigment to another (chl–>e- donation)
- some lost as heat
electron donation
trap chlorophyll (trap energy) -resonance transfer stops at trap chl. loses e- then goes to ETC
energy from photon is transferred to
-electrons
pigments absorb certain photons
- can lose energy as fluorescence (de-excites)
- chlorophyll always fluoresces / absorbs red and reflects green
adventitious roots arise from
shoots
to the inside of periderm
often cork parenchyma that photosynthesize and storage
periderm to the outside
cork cells are dead at maturity
-suberin in cw
statoliths
specialized amyloplasts that signal direction of gravity
-located in the columella of the root cap
everything in endodermis is a
stele
fasicular cambium in primary root stele
between xylem and phloem and is part of the vascular cambium that comes from the pericycle
pneumatophores
in prop roots that stick out of surface of water to aerate roots
endodermis
ending point of vascular cylinder to cortex (casparian strip)
function of endodermis
to prevent water loss/desiccation of the vascular cylinder
