Accumulation of nitrate in the shoot acts as a signal to regulate shoot‐root allocation in tobacco†

@article{Scheible1997AccumulationON,
  title={Accumulation of nitrate in the shoot acts as a signal to regulate shoot‐root allocation in tobacco†},
  author={Wolf-R{\"u}diger Scheible and Marianne Lauerer and E. D. Schulze and Michel Caboche and Mark Stitt},
  journal={Plant Journal},
  year={1997},
  volume={11},
  pages={671-691}
}
Mutants and transformants of tobacco (Nicotiania tabacum L. cv Gatersleben 1) with decreased expression of nitrate reductase have been used to investigate whether nitrate accumulation in the shoot acts as a signal to alter allocation between shoot and root growth. (a) Transformants with very low (1–3% of wild-type levels) nitrate reductase activity had growth rates, and protein, amino acid and glutamine levels similar to or slightly lower than a nitrate-limited wild-type, but accumulated large… 

Lateral root frequency decreases when nitrate accumulates in tobacco transformants with low nitrate reductase activity: consequences for the regulation of biomass partitioning between shoots and root1

It is concluded that nitrate accumulation in the plant leads to decreased root growth via (i) changes in carbon allocation leading to decreased allocation of sugars to root growth, and (ii) a decrease in the number of lateral roots and a shift in the sensitivity with which root growth responds to the sugar supply.

functional nitrate reductase in the roots

Unexpectedly, the C/N balance and the functional equilibrium between root and shoot growth was dis turbed dramatically by the loss of nitrate reduction in the root, and transformed plants showed an altered allocation of amino-N between the root and the shoot.

Nitrate acts as a signal to control gene expression, metabolism and biomass allocation

Tobacco genotypes with decreased activity of nitrate reductase [NR] have been used to establish an in plant screen for processes that are regulated by nitrate. These genotypes resemble

Elevated pCO(2 )favours nitrate reduction in the roots of wild-type tobacco (Nicotiana tabacum cv. Gat.) and significantly alters N-metabolism in transformants lacking functional nitrate reductase in the roots.

Unexpectedly, the C/N balance and the functional equilibrium between root and shoot growth was disturbed dramatically by the loss of nitrate reduction in the root, and transformed plants showed an altered allocation of amino-N between the root and the shoot.

Regulation of resource allocation during reproductive growth in Arabidopsis thaliana L. Heynh

Abi3-1 seeds may be seen as having reduced capacity for growth which causes stimulation of floral meristem development by feedback of sucrose in the phloem, and it is proposed that resource allocation is regulated by competition for resources between sinks maintaining sucrose concentration gradients in thephloem.

Plant response to nitrate starvation is determined by N storage capacity matched by nitrate uptake capacity in two Arabidopsis genotypes.

It was demonstrated that line 432 coped better with NO(3)(-)-starvation, producing higher shoot and root biomass and sustaining maximal growth for a longer time, suggesting that the corresponding nitrate transporters may be preferentially involved under fluctuating N supply conditions.

Expression of a deregulated tobacco nitrate reductase gene in potato increases biomass production and decreases nitrate concentration in all organs

It is concluded that enhancement of nitrate reduction rate leads to higher biomass production, probably by allowing a better allocation of N-resources to photosynthesis and C-metabolism.

The role of nitrate reduction in the anoxic metabolism of roots I. Characterization of root morphology and normoxic metabolism of wild type tobacco and a transformant lacking root nitrate reductase

WT versus LNR-H plants are a suitable tool to re-evaluate the role of nitrate reduction in flooding tolerance and show consistently higher respiration and higher contents of ATP, starch and hexose monophosphates than WT roots.

Genome-wide responses to shoot nitrate satiety are attenuated by external ammonium in Arabidopsis thaliana

It is shown that genome-wide transcriptional responses to shoot nitrate satiety are significantly lowered in the presence of external ammonium especially in the shoot.

Boron deficiency decreases plasmalemma H+-ATPase expression and nitrate uptake, and promotes ammonium assimilation into asparagine in tobacco roots

Results suggest that boron deficiency decreases net nitrate uptake by declining the activity of nitrate transporters rather than affecting their transcript levels, which suggest that this mineral deficiency may promote ammonium assimilation via asparagine synthetase in tobacco roots.
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