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1.
Jerry W. McClure 《Phytochemistry》1974,13(7):1065-1069
Five-day-old etiolated barley shoots respond to brief illumination with red light by increasing their level of PAL ca 50% within 5 hr. When assayed s 相似文献
2.
There was little release of extractable SO4-S during four weeks from CS2 applied by injecting into two S-deficient soils. In this incubation experiment, the rate of CS2 was 30 μg S g−, placement was injection at 9 cm depth, soil temperature was 20°C, and soil moisture tension was 33 kPa. The yield of barley
forage after seven weeks in the greenhouse showed only small increases from 10 or 30 μg S g−1 of CS2 as compared to Na2SO4, on the two soils.
While CS2 supplied little plant available S in the short term, it was an effective inhibitor of nitrification. In the laboratory, or
in the field, the injection of CS2 (with N fertilizers) at a point 9 cm into the soils either stopped or reduced nitrification. In one laboratory experiment,
35 μg of CS2 g−1 of soil with urea reduced nitrification for at least four weeks; and in another experiment 20 μg of CS2 g−1 of soil with aqua NH3 nearly or completely inhibited nitrification at 20 days. In two field experiments, 3 and 12 μg of CS2 g−1 of soil (or 6 and 24 kg ha−1) with aqua NH3 inhibited nitrification from October to the subsequent May. In addition, CS2 reduced the amount of ammonium produced from the soil N, both in these two field experiments and in the laboratory experiments.
That is to say, CS2 injected at a point, inhibited both nitrification and ammonification.
In other field experiments, CS2 at a rate of 10 kg ha−1 was injected in bands 9 cm deep with urea in October, and by May there was still reduced nitrification. Less than half of
the fall-applied urea alone was recovered as mineral N, but with the application of CS2 the recovery was increased to three-quarters.
The yield and N uptake of barley grain was increased where fall-applied banded urea or aqua NH3 received banded CS2, (NH4)2CS3, or K2CS3. The average increase in yield from fall-applied fertilizer, from inhibitor with fall-applied fertilizer, and from spring-applied
fertilizer was 800, 1370, and 1900 kg ha−1, respectively. In the same order, the apparent % recovery of fertilizer N in grain was 24, 42, and 60. 相似文献
3.
4.
The shikimate/arogenate pathway: Link between carbohydrate metabolism and secondary metabolism 总被引:2,自引:0,他引:2
Roy A. Jensen 《Physiologia plantarum》1986,66(1):164-168
5.
《Biocatalysis and Biotransformation》2013,31(1-4):307-316
A new enzymatic reaction of carboxylic esters and ammonia (ammonolysis) was studied. This reaction provides a synthetically useful and mild alternative for the synthesis of amides. Several lipases and one esterase acted as catalyst. Ammonolysis of esters of chiral carboxylic acids gave higher ee values than hydrolysis under comparable reaction conditions. Furthermore, consecutive enzymatic esterification and ammonolysis provided a convenient one-pot synthesis of carboxylic amides from carboxylic acids. 相似文献
6.
J. K. SCHJOERRING A. KYLLINGSBAEK J. V. MORTENSEN S. BYSKOV-NIELSEN 《Plant, cell & environment》1993,16(2):169-178
The activities of glutamine synthetase (GS) and glutamate synthase (GOGAT) in different leaves of field-grown spring barley were measured during the reproductive growth phase in 2 consecutive years. Concurrently, the contents of soluble ammonium ions and free amides in the leaves were determined. The studies were carried out to investigate the relationship between variations in these parameters and emission of NH3 from the plant foliage. GS and GOGAT activities declined very rapidly with leafage. The decline in enzyme activities was followed by an increase in soluble ammonium ions and amides in the leaf tissues. During the same period, about 75% of leaf and stem nitrogen was reallocated to the developing ear. The amount of NH3 volatilized from the foliage during the reproductive growth phase amounted to about 1% of the reallocated nitrogen. The experimental years were characterized by very favourable conditions for grain dry matter formation and for re-utilization of nitrogen mobilized from leaves and stems. Ammonia volatilization occurring under conditions with declining GS and GOGAT activities and increasing tissue concentrations of NH4+ may be useful in protecting the plant from accumulation of toxic NH3 and NH4+ concentrations in the tissues. 相似文献
7.
We investigated the synthesis and translocation of amino compounds in Parasponia, a genus of the Ulmaceae that represents the only non-legumes known to form a root nodule symbiosis with rhizohia. In the xylem sap of P. andersonii we identified asparagine. aspartate. glutamine, glutamated significant quantities of a non-protein amino acid. 4-methylglutamte(2-amino-4-methylpentanedioic acid). This identification was confirmed by two methods, capillary gas chromatography (GC) electron ionization (El) mass spectrometry (MS) and reverse phase high pressure liquid chromatography (HPLC) analysis of derivatized compounds. In leaf, root and nodule samples from P. andersonii and P. parviflora we also identified the related compounds 4-methyleneglutamate and 4-methyleneglulamine. Using 15N2 labelling and GC-Ms analysis of root nodule extracts we followed N2 fixation and ammonia assimilation in P. andersonii root nodules and observed Label initially in glutamine and subsequently in glutamate, suggesting operation of the glutamine synthetase/glutamine:2-oxoglutarate aminotransferase (GS/GOGAT) pathway. Importantly, we observed the incorporation of significant quantities of 15N into 4-methylglutamate in nodules, demonstrating the de nova synthesis of this non protein amino acid and suggesting a role in the translation of N in symbioticParasponia. 相似文献
8.
Haiwei Luo Bradley B Tolar Brandon K Swan Chuanlun L Zhang Ramunas Stepanauskas Mary Ann Moran James T Hollibaugh 《The ISME journal》2014,8(3):732-736
Previous studies based on analysis of amoA, 16S ribosomal RNA or accA gene sequences have established that marine Thaumarchaeota fall into two phylogenetically distinct groups corresponding to shallow- and deep-water clades, but it is not clear how water depth interacts with other environmental factors, including light, temperature and location, to affect this pattern of diversification. Earlier studies focused on single-gene distributions were not able to link phylogenetic structure to other aspects of functional adaptation. Here, we analyzed the genome content of 46 uncultivated single Thaumarchaeota cells sampled from epi- and mesopelagic waters of subtropical, temperate and polar oceans. Phylogenomic analysis showed that populations diverged by depth, as expected, and that mesopelagic populations from different locations were well mixed. Functional analysis showed that some traits, including putative DNA photolyase and catalase genes that may be related to adaptive mechanisms to reduce light-induced damage, were found exclusively in members of the epipelagic clade. Our analysis of partial genomes has thus confirmed the depth differentiation of Thaumarchaeota populations observed previously, consistent with the distribution of putative mechanisms to reduce light-induced damage in shallow- and deep-water populations. 相似文献
9.
Rongting Xu Hanqin Tian Shufen Pan Stephen A. Prior Yucheng Feng William D. Batchelor Jian Chen Jia Yang 《Global Change Biology》2019,25(1):314-326
Excessive ammonia (NH3) emitted from nitrogen (N) fertilizer applications in global croplands plays an important role in atmospheric aerosol production, resulting in visibility reduction and regional haze. However, large uncertainty exists in the estimates of NH3 emissions from global and regional croplands, which utilize different data and methods. In this study, we have coupled a process‐based Dynamic Land Ecosystem Model (DLEM) with the bidirectional NH3 exchange module in the Community Multiscale Air‐Quality (CMAQ) model (DLEM‐Bi‐NH3) to quantify NH3 emissions at the global and regional scale, and crop‐specific NH3 emissions globally at a spatial resolution of 0.5° × 0.5° during 1961–2010. Results indicate that global NH3 emissions from N fertilizer use have increased from 1.9 ± 0.03 to 16.7 ± 0.5 Tg N/year between 1961 and 2010. The annual increase of NH3 emissions shows large spatial variations across the global land surface. Southern Asia, including China and India, has accounted for more than 50% of total global NH3 emissions since the 1980s, followed by North America and Europe. Rice cultivation has been the largest contributor to total global NH3 emissions since the 1990s, followed by corn and wheat. In addition, results show that empirical methods without considering environmental factors (constant emission factor in the IPCC Tier 1 guideline) could underestimate NH3 emissions in context of climate change, with the highest difference (i.e., 6.9 Tg N/year) occurring in 2010. This study provides a robust estimate on global and regional NH3 emissions over the past 50 years, which offers a reference for assessing air quality consequences of future nitrogen enrichment as well as nitrogen use efficiency improvement. 相似文献
10.