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11.
The genetics of nitrogen use in hexaploid wheat: N utilisation, development and yield 总被引:4,自引:0,他引:4
Habash DZ Bernard S Schondelmaier J Weyen J Quarrie SA 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(3):403-419
A genetic study is presented for traits relating to nitrogen use in wheat. Quantitative trait loci (QTLs) were established
for 21 traits relating to growth, yield and leaf nitrogen (N) assimilation during grain fill in hexaploid wheat (Triticum aestivum L.) using a mapping population from the cross Chinese Spring × SQ1. Glutamine synthetase (GS) isozymes and estimated locations
of 126 genes were placed on the genetic map. QTLs for flag leaf GS activity, soluble protein, extract colour and fresh weight
were found in similar regions implying shared control of leaf metabolism and leaf size. Flag leaf traits were negatively associated
with days to anthesis both phenotypically and genetically, demonstrating the complex interactions of metabolism with development.
One QTL cluster for GS activity co-localised with a GS2 gene mapped on chromosome 2A, and another with the mapped GSr gene on 4A. QTLs for GS activity were invariably co-localised with those for grain N, with increased activity associated
with higher grain N, but with no or negative correlations with grain yield components. Peduncle N was positively correlated,
and QTLs co-localised, with grain N and flag leaf N assimilatory traits, suggesting that stem N can be indicative of grain
N status in wheat. A major QTL for ear number per plant was identified on chromosome 6B which was negatively co-localised
with leaf fresh weight, peduncle N, grain N and grain yield. This locus is involved in processes defining the control of tiller
number and consequently assimilate partitioning and deserves further examination.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
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Al Dera H Habgood MD Furness JB Brock JA 《American journal of physiology. Heart and circulatory physiology》2012,302(3):H752-H762
In patients with spinal cord injury (SCI), somatosympathetic reflexes produce exaggerated decreases in skin blood flow below the lesion. This hypoperfusion appears to result from an increased responsiveness of cutaneous arterial vessels to neural activation. Here we investigated the mechanisms that underlie SCI-induced enhancement of neurovascular transmission in a cutaneous vessel, the rat tail artery. Isometric contractions of arterial segments from T11 spinal cord transected and sham-operated rats were compared 6 wk postoperatively. SCI more than doubled the amplitudes of contractions of arteries in response to moderate frequencies of nerve stimulation (0.1 to 1 Hz). In arteries from SCI rats, but not those from sham-operated rats, the L-type Ca(2+) channel blocker nifedipine (1 μM) reduced the amplitudes of nerve-evoked contractions. Furthermore, while the sensitivity to the agonists phenylephrine (α(1)-adrenoceptor selective) and clonidine (α(2)-adrenoceptor selective) did not differ significantly between arteries from SCI and sham-operated rats, nifedipine had a greater inhibitory effect on contractions to both agents in arteries from SCI rats. Although sensitivity to clonidine was unchanged, SCI selectively reduced the contribution of postjunctional α(2)-adenceptors to nerve-evoked contractions. In arteries from unoperated rats, the L-type channel agonist BAY K 8644 (0.1 μM) produced a similar enhancement of nerve-evoked contraction to that produced by SCI and also selectively reduced the contribution of α(2)-adrenceptors to these responses. Together the findings demonstrate that the SCI-induced enhancement of neurovascular transmission in the rat tail artery can largely be accounted for by an increased contribution of L-type Ca(2+) channels to activation of the vascular smooth muscle. 相似文献
14.
The regulation of component processes of photosynthesis in transgenic tobacco with decreased phosphoribulokinase activity 总被引:2,自引:0,他引:2
Dimah Z. Habash Martin A. J. Parry Saroj Parmar Matthew J. Paul Simon Driscoll Jacqueline Knight John C. Gray David W. Lawlor 《Photosynthesis research》1996,49(2):159-167
Tobacco plants (Nicotiana tabacum L.) transformed with an inverted cDNA encoding ribulose 5-phosphate kinase (phosphoribulokinase,PRK; EC 2.7.1.19) were employed to study the in vivo relationship between photosynthetic electron transport and the partitioning of electron transport products to major carbon metabolism sinks under conditions of elevated ATP concentrations and limited ribulose 1,5-bisphosphate (RuBP) regeneration. Simultaneous measurements of room temperature chlorophyll fluorescence and CO2 gas exchange were conducted on intact leaves. Under ambient CO2 concentrations and light intensities above those at which the plants were grown, transformants with only 5% of PRK activity showed down-regulation of PS II activity and electron transport in response to a decrease in net carbon assimilation when compared to wild-type. This was manifested as a decline in the efficiency of PS II electron transport (PS II), an increase in dissipation of excess absorbed light in the antennae of PS II and a decline in: total linear electron transport (J1), electron transport dedicated to carbon assimilation (JA) and electron transport allocated to photorespiration (JL). The transformants showed no alteration in the Rubisco specificity factor measured in vitro and calculated in vivo but had a relatively smaller ratio of RuBP oxygenation to carboxylation rates (vo/vc), due to a higher CO2 concentration at the carboxylation site (Cc). The relationship between PS II and CO
2was similar in transformants and wild-type under photorespiratory conditions demonstrating no change in the intrinsic relationship between PS II function and carbon assimilation, however, a novel result of this study is that this similar relationship occurred at different values of quantum flux, J1, JA, JL and vo/vc in the transformant. For both wild-type and transformants, an assessment was made of the possible presence of a third major sink for electron transport products, beside RuBP oxygenation and carboxylation, the data provided no evidence for such a sink.Abbreviations Cc
CO2 concentration at the site of carboxylation
- Ci
intercellular CO2 concentration
- gm
mesophyll conductance to CO2
- J1
total linear electron flow
- JA
linear electron flow allocated to CO2 assimilation
- Jc
linear electron flow supporting carbon reduction and oxidation cycles
- JL
linear electron flow allocated to photorespiration (RuBP oxygenation and fixation of released photorespiratory CO2)
- PRK
phosphoribulokinase
- qP, qN
coefficients for photochemical and non-photochemical quenching of fluorescence respectively
- Rubisco
ribulose 1,5-bisphosphate carboxylase-oxygenase
- S
Rubisco specificity to CO2/O2
- vc, vo
rates of RuBP carboxylation and RuBP oxygenation, respectively
- CO
2
relative quantum yield of CO2 assimilation
- C
maximum CO
2 under non-photorespiratory conditions
- exc
the efficiency of excitation capture by open PS II centres
- PS II
relative quantum yield of PS II electron transport 相似文献
15.
High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown. 相似文献
16.
Gene expression, cellular localisation and function of glutamine synthetase isozymes in wheat (Triticum aestivum L.) 总被引:1,自引:0,他引:1
17.
Al Dera Hussain Alassiri Mohammed Eleawa Samy M. AlKhateeb Mahmoud A. Hussein Abdelaziz M. Dallak Mohammad Sakr Hussein F. Alqahtani Sultan Khalil Mohammad A. 《Neurochemical research》2019,44(8):1851-1868
Neurochemical Research - This study investigated the expression pattern, regulation of expression, and the role of hippocampal small-conductance Ca2+-activated K+ (SK) channels in memory deficits... 相似文献
18.
18β-Glycyrrhetinic acid (18β-GA) has been proposed as a promising hepatoprotective agent. The current study aimed to investigate the protective action and the possible mechanisms of 18β-GA against cyclophosphamide (CP)-induced liver injury in rats, focusing on the role of peroxisome proliferator-activated receptor gamma (PPARγ) and NF-E2-related factor-2 (Nrf2). Rats were administered 18β-GA at doses 25 and 50 mg/kg 2 weeks prior to CP injection. Five days after CP administration, animals were sacrificed and samples were collected. CP induced hepatic damage evidenced by the histopathological changes and significant increase in serum pro-inflammatory cytokines, liver marker enzymes, and liver lipid peroxidation and nitric oxide (NO) levels. 18β-GA counteracted CP-induced oxidative stress and inflammation as assessed by restoration of the antioxidant defenses and diminishing of pro-inflammatory cytokines, lipid peroxidation, and NO production. These hepatoprotective effects appear to depend on activation of Nrf2 and PPARγ, and subsequent suppression of nuclear factor-kappa B. In conclusion, the present study provides evidence that 18β-GA exerts hepatoprotective effects against CP through induction of antioxidant defenses and suppression of inflammatory response. This report also confers new information that 18β-GA protects liver against the toxic effect of chemotherapeutic alkylating agents via activation of Nrf2 and PPARγ. 相似文献
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New perspectives on glutamine synthetase in grasses 总被引:2,自引:0,他引:2
Swarbreck SM Defoin-Platel M Hindle M Saqi M Habash DZ 《Journal of experimental botany》2011,62(4):1511-1522
Members of the glutamine synthetase (GS) gene family have now been characterized in many crop species such as wheat, rice, and maize. Studies have shown that cytosolic GS isoforms are involved in nitrogen remobilization during leaf senescence and emphasized a role in seed production particularly in small grain crop species. Data from the sequencing of genomes for model crops and expressed sequence tag (EST) libraries from non-model species have strengthened the idea that the cytosolic GS genes are organized in three functionally and phylogenetically conserved subfamilies. Using a bioinformatic approach, the considerable publicly available information on high throughput gene expression was mined to search for genes having patterns of expression similar to GS. Interesting new hypotheses have emerged from searching for co-expressed genes across multiple unfiltered experimental data sets in rice. This approach should inform new experimental designs and studies to explore the regulation of the GS gene family further. It is expected that understanding the regulation of GS under varied climatic conditions will emerge as an important new area considering the results from recent studies that have shown nitrogen assimilation to be critical to plant acclimation to high CO(2) concentrations. 相似文献