MARC 主機 00000nam 2200000 a 4500
001 AAI3370236
005 20110907152210.5
008 110907s2009 ||||||||s|||||||| ||eng d
020 9781109306231
035 (UMI)AAI3370236
040 UMI|cUMI
100 1 Lovin, Mary Elizabeth
245 10 Exploring the role of auxin in phenotypic plasticity in
Arabidopsis thaliana root development|h[electronic
resource]
300 196 p
500 Source: Dissertation Abstracts International, Volume: 70-
08, Section: B, page: 4689
500 Adviser: Gloria K. Muday
502 Thesis (Ph.D.)--Wake Forest University, 2009
520 Auxin is a plant hormone that positively regulates the
initiation and emergence of lateral roots. In this study
we used several approaches to reduce auxin transport
moving either from the shoot toward the root apex or from
the root tip toward the base and examined the effect of
these treatments on lateral root initiations and
emergence. Our results are consistent with shoot derived
auxin driving lateral root initiation, while we could
detect no role for root tip auxin in lateral root
initiation or elongation. We examined how environmental
variables regulate root formation with a focus on day
length and growth temperature and found that elevated
temperature and increased day length positively regulate
root formation. We explored several mechanisms by which
root initiation is enhanced under these conditions
including elevated auxin synthesis, transport, and
signaling. Both auxin accumulation and auxin dependent
gene expression increase during these treatments,
suggesting a mechanistic basis for regulation of root
branching. We also asked whether populations isolated from
different latitudes might exhibit differences in root
architecture. Environmental variables across a latitudinal
gradient have been shown to both transiently affect growth,
development, and physiological responses, as well drive
the evolution of ecotypes with unique genotypes that
increase fitness. We hypothesized that early root
architecture as well as resource allocation would differ
for populations across latitude based on the latitudinal
provenance. We observed differences in lateral root
initiation, elongation, and developmental patterns under
higher UV that followed a latitudinal cline. In
populations from higher latitude, there were fewer lateral
root primordia and emerged lateral roots, as well as less
shoot biomass. We observed that in mature plants grown at
lower UV levels, the photosynthetic rate and shoot biomass
were lower in populations from higher latitudes leading to
a different carbon balance. Root respiration and root
biomass did not change between these populations isolated
from different latitudes. Together these results provide
insight into the hormonal, environmental, and genetic
controls of root developmental patterning
590 School code: 0248
650 4 Biology, Botany
650 4 Biology, Plant Physiology
690 0309
690 0817
710 2 Wake Forest University
773 0 |tDissertation Abstracts International|g70-08B
856 40 |uhttps://pqdd.sinica.edu.tw/twdaoapp/servlet/
advanced?query=3370236
912 PQDT
