Open Access Repository
The use of gibberellin mutants to explore the role of microtubules in stem elongation
Downloads
Downloads per month over past year
|
PDF
(Whole thesis)
whole_Kitchener...pdf | Download (12MB) Available under University of Tasmania Standard License. | Preview |
Abstract
Six single gene mutants of garden pea (Pisum sativum L.) were utilised to further
examine the control of internode elongation. These short mutants could be divided into
two types; GA-synthesis (1s, le), and GA-response ( 1k, lka, lkb, 1w) types. They
were compared with the parental wild-type cv. Torsdag in an analysis of the changes
in orientation of cortical microtubules in expanding dark-grown internode tissue with
distance from the apical hook. Immunofluorescence analysis of FITC-labelled cortical
microtubules in tangential sections of epidermal cells and longitudinal sections of
subepidermal cortical cells of the mutants and wild-type plants revealed a shift away
from the wild-type microtubule arrangement toward less transverse microtubule arrays
in the mutants. This lower average microtubule orientation (resulting from a reduced
proportion of cells with predominantly transverse microtubule arrangement) correlated
with decreases in the rate and distribution of extension growth along internode 3 of
dark-grown mutants, providing additional circumstantial support for the role of
transverse microtubule orientation in extension growth.
Analysis of microtubule arrangement and growth profiles of the GA-synthesis
mutants, le and is, revealed overall reductions in average microtubule orientation and
rate and distribution of growth in comparison to wild-type plants. These changes
correspond to the mutants' reduced endogenous GA1 content and implicate GA1 in the
microtubule-mediated regulation of both rate and distribution of extension growth
along the epicotyl. Exogenous application of GA1 to GA-synthesis mutants resulted in
a shift in average microtubule orientation toward the wild-type arrangement, and a
corresponding increase in internode length, substantiating a role for GA1 in
microtubule-mediated extension growth.
Average microtubule orientation in le and ls was never as transverse as in the wildtype,
and transverseness of the array decreased more rapidly than in the wild-type over
the same length of epicotyl, implicating GA1 in both the initial organization of
microtubules and the maintenance of stability of transverse arrays.
Item Type: | Thesis - PhD |
---|---|
Authors/Creators: | Kitchener, Anne Elizabeth |
Keywords: | Stems (Botany), Growth (Plants), Plants |
Copyright Holders: | The Author |
Copyright Information: | Copyright 1994 the Author - The University is continuing to endeavour to trace the copyright |
Additional Information: | Thesis (Ph.D.)--University of Tasmania, 1995. Includes bibliographical references (p. 131-161) |
Item Statistics: | View statistics for this item |
Actions (login required)
![]() |
Item Control Page |