Chapter 14 Flashcards
Embryogenesis
what is development governed by
gene networks
position
exert strong influence on developmental processes
how does embryogenesis arise
from cell division and expansion instead of movement
where does embryogenesis take place
ovule of all seed plants
apical cell
smaller cell; establishes what it will be
basal cell
tissues that will attach itself to an ovule and you get the suspensor
what are the five stages of Arabidopsis embryogenesis
zygotic, globular, heart, torpedo, mature
what is the globular stage of embryogenesis
globe shaped embryo; multiple division, eventually get the protoderm
what is the zygotic stage of embryogenesis
fusion of gametes
what is the heart shape stage of embryogenesis
cells on either side dip to develop cotyledons
what is the mature stage of embryogenesis
mature embryo, cotyledons are bent, dehydration stage, metabolically inactive
what are the differences between maize embryogenesis and Arabidopsis
maize has a transition, coleoptile, leaf primordia stages instead of heart in the arabidopsis
what is the transition stage of embryogenesis
scutellum develops, certain specializations, SAM coleoptile will be distinct
what happens in the coleoptile stage of embryogenesis
modified structure that forms a tube; distinct SAM and RAM; development of first leaf
what happens during maturation of maize embryo
development of a radicle
periclinal
cell plate is parallel to the tissue surface
anticlinal
cell plate is perpendicular to the tissue surface; requires regulated communication between cells
polar transport
directional movement of auxin in a programmed directional movement
what is polar auxin transport mediated by
efflux carriers
basipetal v. acropetal auxin movement
apical to basal
rootward v. shootward movement of auxin
from shoot to root
what is the pH of the cell wall
5-5.5
how does polar auxin transport work
auxin in cell walls are protonated b/c of proton pumping; IAA-H loses H+ to turn into IAA
which auxin form can diffuse across the plasma membrane (think protonation)
IAA-H
Explain figure 14.10
done
PIN proteins
drive the movement of auxin; oriented in different parts of the cells
Look at figure 14.11
done
how does auxin flow in early heart stages
auxin is transported laterally up the sides; directional flow of auxin from flank to tip basipetally
what determines where you get tissue layers
radial patterns are the guide
what do periclinal divisions result in
concentric layers
what is cytokinin needed for
development of phloem; if there is none/ the receptor is not working you get no phloem
Apical meristems development is determined by what
where the embryo developed
how are meristematic cells formed
clusters of slowly developing cells that have undetermined fate divide; they are capable of dividing more rapidly than others so they make up the meristems
quiescent center
lense shaped cell; core of the center where the RAM develops
what is the take away between auxin and cytokinin ratios
there has to be an even ratio to get normal root development; too little cytokinin means more auxin which results in abnormal roots
Review figure 14.17
done
