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Acclimation of photosynthesis and respiration is asynchronous in response to changes in ... |
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Campbell C, Atkinson L, Zaragoza-Castells J, Lundmark M, Atkin O, Hurry V
Acclimation of photosynthesis and respiration is asynchronous in response to changes in temperature regardless of plant functional group.
New Phytologist: 2007 176:375-389
Abstract
Both indole acetic acid (IAA) and gibberellins (GAs) stimulate cell and
organ growth. We have examined GA/IAA cross-talk in cambial growth of
hybrid aspen (Populus tremula×tremuloides). Decapitated
trees were fed with IAA and GA, alone and in combination. Endogenous
hormone levels after feeding were measured, by mass spectrometry, in
the stem tissues below the point of application. These stem tissues
with defined hormone balances were also used for global transcriptome
analysis, and the abundance of selected transcripts was measured by
real-time reverse-transcription polymerase chain reaction. By feeding
isotope-labeled IAA, we demonstrated that GA increases auxin levels in
the stem by stimulating polar auxin transport. This finding adds a new
dimension to the concept that the endogenous GA/IAA balance in plants
is determined by cross-talk between the two hormones. We also show that
GA has a common transcriptome with auxin, including many transcripts
related to cell growth. This finding provides molecular support to
physiological experiments demonstrating that either hormone can induce
growth if the other hormone is absent/deficient because of mutations or
experimental treatments. It also highlights the potential for extensive
cross-talk between GA- and auxin-induced responses in vegetative growth
of the intact plant. The role of endogenous IAA and GA in wood
development is discussed.
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Publications 2007 
