铵离子对不同基因型水稻吸收硝酸根离子的影响1

NH+4可在很短时间内影响两种不同水稻亚种吸收NO-3,即可以影响NO-3的最初跨膜运输.籼型稻在NH+4存在时对NO-3吸收有促进,而粳型稻NO-3吸收则明显减少.     

Effect of Pyrolysis Temperature on Chemical and Surface Properties of Biochar of Rapeseed (Brassica napus L.)

The biochar is an important carbon-rich product that is generated from biomass sources through pyrolysis. Biochar (charcoal) can be both used directly as a potential source of solid biofuels and as soil amendments for barren lands. The aim of this study was investigate influence of pyrolysis temperature on the physicochemical properties and structure of biochar. The biochars were produced by pyrolysis of rapeseed (Brassica napus L.) using a fixed-bed reactor at different pyrolysis temperatures (400–700°C). The produced biochars were characterized by proximate and elemental analysis, Brunauer–Emmett–Teller (BET) surface area, particle size distributions, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy. The results showed that both chemical and surface properties of the biochars were significantly affected by the pyrolysis temperature. Aromatic hydrocarbons, hydroxyl and carbonyl compounds were the majority components of the biochar. The biochar obtained at 700°C had a high fixed carbon content (66.16%) as well as a high heating value, and therefore it could be used as solid fuel, precursor in the activated carbons manufacture (specific surface area until 25.38 m² g^?1), or to obtain category-A briquettes.     

Effects of Nitrogen Deficiency on the Absorption of Nitrate and Ammonium by Barley Plants

When young barley plants which had been supplied with nitratewere deprived of this source of N, an enhanced capacity forabsorption of either nitrate or ammonium ions developed, reachinga maximum in about 3 d under the particular experimental conditionsused. The net uptake rate of either nutrient was then approximatelythree times that in plants which had received nitrate throughout.Likewise, withholding external N from plants previously growingwith ammonium caused a 2.4-fold increase in their subsequentcapacity to absorb that ion, compared with control plants grownwith an uninterrupted ammonium supply. Accelerated nitrate uptakein N-starved plants was not accompanied by additional phosphateor sulphate absorption, but the plants had the capacity to absorbmore potassium, whether or not ammonium was also present inthe solution. Indirect evidence from analyses of root tissuesuggests that these responses to mild N-stress may depend onsome property of an N fraction which does not include nitrateor ammonium. Hordeum vulgare, barley, nitrogen, ammonium, nitrate, N-deficiency, absorption     

Reduction of Nitrite and Nitrate to Ammonium on Pyrite

An important constraint on the formation of the building blocks of life in the Hadean is the availability of small, activated compounds such as ammonia (NH(3)) relative to its inert dinitrogen source. Iron-sulfur particles and/or mineral surfaces have been implicated to provide the catalytic active sites for the reduction of dinitrogen. Here we provide a combined kinetic, spectroscopic, and computational modeling study for an alternative source of ammonia from water soluble nitrogen oxide ions. The adsorption of aqueous nitrite (NO (2) (-) ) and nitrate (NO (3) (-) ) on pyrite (FeS(2)) and subsequent reduction chemistry to ammonia was investigated at 22°C, 70°C, and 120°C. Batch geochemical and in situ Attenuated Total Reflection - Fourier Transform Infrared (ATR-FTIR) spectroscopy experiments were used to determine the reduction kinetics to NH(3) and to elucidate the identity of the surface complexes, respectively, during the reaction chemistry of NO (2) (-) and NO (3) (-) . Density functional theory (DFT) calculations aided the interpretation of the vibrational data for a representative set of surface species. Under the experimental conditions used in this study, we detected the adsorption of nitric oxide (NO) intermediate on the pyrite surface. NH(3) production from NO (2) (-) occurred at 70 and 120°C and from NO (3) (-) occurred only at 120°C.     

硫酸铵或尿素代替硝酸铵的MS培养基对苹果、草莓和葡萄组培苗继代的效应

以硫酸铵或者尿素代替MS基本培养基中的硝酸铵,继代培养苹果砧木‘山定子’、草莓品种‘哈尼’和葡萄品种‘里扎马特’的组培苗的结果表明,以尿素替代硝酸铵的培养基不适于苹果、草莓和葡萄组培苗的生长。以硫酸铵代替硝酸铵的培养基中,苹果、草莓和葡萄组培苗生长正常。与正常的MS培养基中生长的组培苗相比,加入3.4g·L^-1硫酸铵的MS培养基中继代的植物叶片平展,叶色嫩绿,植物幼嫩组织含水量高,植株生长旺盛。     

Nitrate, Ammonium and Kinetin Effects on Growth and Enzyme Activities of Paul's Scarlet Rose Callus

Factorial experiments using the three variables nitrate, ammonium, and kinetin at six different concentrations each (nitrate 4.64 to 215 mM; ammonium 2.15 to 100 mM; and kinetin 0.1 to 4.64 mg/l) were set up to measure the effects of each of these factors, and their interactions, on the fresh weight, protein, and enzyme activities of callus of Paul's Scarlet Rose. Optimum fresh weight values were obtained with nitrate at 46.4 mM. Ammonium inhibited growth at concentrations above 2.15 mM, and kinetin had no significant effect. Significant interaction between nitrate and ammonium effects on growth was found. Kinetin did not interact significantly with either nitrate or ammonium to influence the fresh weight. The specific activity of glutamate dehydrogenase (NAD) in the aminating reaction increased with increasing ammonium concentrations to 21.5; at higher concentrations the activity remained high. Glutamine synthetase specific activity was constant over a large range of nitrate and ammonium concentrations, increasing only when nitrate went from 46.4 to 100 mM. Glutamine synthetase was sensitive to the nitrate: ammonium interaction. Specific activity decreased at progressively higher ammonium levels when nitrate concentration increased. No glutamate synthase activity was detected at optimal nitrate concentrations.     

Effects of Exposure to Ammonium and Transplant Shock upon the Induction of Nitrate Absorption

In barley (Hordeum vulgare L. cv Steptoe) seedlings, the time course for induction of root nitrate absorption varied significantly with pretreatment. Net nitrate uptake of nitrogen-deprived plants more than doubled during the 12 hours after first exposure to nitrate. For these plants, gentle physical disturbance of the roots inhibited net nitrate absorption for more than 6 hours and potassium absorption for 2 hours. Pretreatment with ammonium appeared sufficient to induce nitrate absorption; plants either grown for 2 weeks on or exposed for only 10 hours to a medium containing ammonium as a sole nitrogen source showed high rates of net nitrate uptake when first shifted to a medium containing nitrate. Gentle physical manipulation of these plants inhibited nitrate absorption for 2 hours and potassium absorption for more than 12 hours. These results indicate (a) that experimental protocols should avoid physical manipulation of the roots when-ever possible and (b) that ammonium or a product of ammonium assimilation can induce nitrate absorption.     

Nitrate Nutrition and Temperature Effects on Wheat: Photosynthesis and Photorespiration of Leaves

Lawlor, D. W., Boyle, F. A., Young, A. T., Keys, A. J. and Kendall,A. C. 1987. Nitrate nutrition and temperature effects on wheat:photosynthesis and photorespiration of leaves.—J. exp.Bot. 38: 393–408. Photosynthetic and photorespiratory carbon dioxide exchangeby the third leaf of spring wheat (Triticum aestivum cv. Kolibri),was analysed for plants grown at 13/10 °C (day/night temperature)and 23/18 °C with two rates of nitrate fertilization (abasal rate, — N, and a 4-fold larger rate, +N) and, insome experiments, with two photon fluxes. Net photosynthesiswas greatest at the time of maximum lamina expansion, and forleaves grown with additional nitrate. Maximum rate of photosynthesis,carboxylation efficiency and photochemical efficiency at maturitywere slightly decreased by nitrate deficiency but photosystemactivity was similar under all conditions. As leaves aged, photosynthesisand photochemical efficiency decreased; carboxylation efficiencydecreased more than photochemical efficiency particularly withbasal nitrate. Low oxygen increased the carboxylation and photochemicalefficiencies, and increased the maximum rate of assimilationby a constant proportion in all treatments. Photorespiration,measured by CO₂ efflux to CO₂-free air, by ¹⁴CO₂ uptake, andfrom compensation concentration, was proportional to assimilationin all treatments. It was greater, and formed a larger proportionof net photosynthesis, when measured in warm than in cold conditionsbut was independent of growth conditions. Assimilation was relatedto RuBPc-o activity in the tissue. Relationships between photosynthesis,photorespiration and enzyme complement are discussed. Key words: Wheat, leaves, nitrate nutrition, temperature effect, photosynthesis, photorespiration     

Nitrate Nutrition and Temperature Effects on Wheat: Enzyme Composition, Nitrate and Total Amino Acid Content of Leaves

Lawlor, D. W., Boyle, F. A., Kendall, A. C. and Keys, A. J.1987. Nitrate nutrition and temperature effects on wheat: Enzymecomposition, nitrate and total amino acid content of leaves.—J.exp. Bot. 38: 378–392. Wheat plants were grown in controlled environments in two temperatureregimes with two rates of nitrate fertilization. In some experimentstwo light intensities were combined with the nitrogen and temperaturetreatments. The composition of the third leaf was studied fromsoon after emergence until early senescence. The amounts ofchlorophyll, soluble protein, ribulose bisphosphate carboxylase-oxygenase(RuBPc-o) protein, nitrate, and total amino acids were measuredtogether with the activities of RuBPc-o, fructose- 1,6-bisphosphatase,glycolate oxidase, carbonic anhydrase, nitrate reductase, glutaminesynthetase and serine- and glutamate-glyoxylate aminotransferases.Additional nitrate supply increased the amounts, per unit leafarea, of chlorophyll, total soluble protein and RuBPc-o proteinand the activities of all the enzymes. The ratio of RuBP carboxylaseto RuBP oxygenase activity, when measured at constant CO²/O²ratio and temperature, was unaffected by growth conditions orleaf age. Leaves grown at the lower temperature, especiallywith more nitrate, contained much more soluble protein, nitratereductase, fructose bisphosphatase and free amino acids perunit area than the plants grown in the warmer conditions. However,young leaves grown in the warm contained more nitrate than thosegrown in the cool. Amounts of protein, amino acids and chlorophylland most enzyme activities reached maxima near full leaf expansionand decreased with age; additional nitrate slowed the decreaseand senescence was delayed. Nitrate content and nitrate reductaseactivities were highest in leaves before full expansion andthen fell rapidly after full expansion. Increased light intensityincreased the content of RuBPc-o protein at the higher rateof nitrate supply. Chloroplast components and, to a lesser extent,peroxisomal enzymes associated with photosynthetic nitrogenassimilation changed in proportion with different treatmentsbut nitrate reductase activity was not closely related to chloroplastenzymes. Control of tissue composition in relation to environmentalconditions is discussed. Key words: Nitrate nutrition, temperature, wheat, enzyme, amino acid, leaves, ribulose bisphosphate carboxylase oxygenase, nitrate reductase     

Mutagenicity of the Pyrolysis Products of Ammonium Salts

One molecular species of prothoracicotropic hormone with a molecular weight of about 22, 000 (22K-PTTH) of the silkworm, Bombyx mori, was isolated from 5 × 10⁵ adult heads. The purification procedure consisted of 16 steps including defatting, salt-extraction, fractional precipitations, conventional column chromatographies, and high performance liquid chromatographies. An approximately 5 × 10⁶-fold purification was attained to yield 5.4 μg (0.25 nmol) of the pure hormone with a recovery of 3.3%. Injection of 0.11 ng of the purified 22K-PTTH could elicit adult development in a brainless Bombyx pupa. 22K-PTTH is a basic protein (pI 7.7 ~ 8.7) containing disulfide bond(s). The amino-terminal amino acid sequence of 22K-PTTH was determined to be Gly-Asn-Ile-Gln-Val-Glu-Asn-Gln-Ile-Pro-Asp-Pro-.     

Preferential Assimilation of Ammonium Ions from Ammonium Nitrate Solutions by Apple Seedlings

Apple seedlings, Pyrus malus L., were grown in complete nutrient solutions containing nitrate, ammonium, or ammonium plus nitrate as the nitrogen source. Uptake of nitrogen was calculated from depletion measurements of the nutrient solutions and by using ¹⁵N labelled nitrate and ammonium salts. If the plants received nitrogen as ammonium only or as nitrate only, the amounts of nitrogen taken up were similar. However, if the seedlings were supplied with ammonium nitrate, the amount of nitrate-nitrogen assimilated was only half that of ammonium. Nevertheless, if ammonium and nitrate were supplied to a plant with a split-root system, with each root half receiving a different ion, the uptakes were similar. The possibility of independent inhibition by ammonium of both nitrate uptake and reduction in the roots is discussed.     

Trichlorfon-Induced Inhibition of Nitrate and Ammonium Uptake in Cyanobacteria

The possibility that the primary effect of the toxic insecticidetrichlorfon is an inhibition of nitrate uptake in cyanobactenahas been investigated. A drastic reduction in the rate of uptakeis detected 3 h after the addition of the insecticide to batchcultures of nabaena PCC 7119. The dose-response curves indicatea relationship between the degree of inhibition of nitrate uptakeand the reduction of chlorophyll content and growth. Nitratereductase (ferredoxin : nitrate reductase, EC 1.7.99.4 [EC] ) activityis also lowered as a result of insecticide action. When AnabaenaPCC 7119 cells are grown with ammonium as a source of combinednitrogen, trichlorfon reduces the rate of ammonium uptake. Therate of uptake of both nitrate and ammonium is restored uponwashing the cells. Ultrastructural analysis of Anabaena nitrate-growncells shows that trichlorfon does not damage thylakoid membranes,but brings about the accumulation of enlarged cyanophycin granulesand the increase of carboxysome number. Nitrate uptake rateand chlorophyll and phycobiliprotein contents are also reducedby insecticide treatment in the cyanobacteria SynechococcusUAM 211, GloeothecePCC 6501, Plectonema calothricoides, NostocUAM 205 and Chlorogloeopsis PCC 6912. These results are consistentwith the inhibition of nitrate uptake due to weak adsorptionof trichlorfon to the plasmalemma being the main effect of theinsecticide on cyanobacterial metabolism. Key words: Nitrate uptake, cyanobacteria, Anabaena, ammonium uptake, trichlorfon     

蔗糖和硝酸铵对黄连悬浮培养细胞生长和小檗碱含量的影响

在６、７－Ｖ液体培养基中较为适合黄连细胞生长的蔗糖浓度为．３％,当蔗糖浓度增加到７％时,细胞生长速率开始下降,但小檗碱含量提高到５．２０％．小檗碱产率为４５６．６０ｍｇ／Ｌ（２３天）。基本培养基中随着补加ＮＨ４ＮＯ３浓度的增加,抑制细胞生长愈严重;补加０．８ｇ／ＬＮＨ４ＮＯ３的小檗碱含量比未加的增加约１０％,随着浓度的增加又急剧下降。     

Water Stress Effects on Nitrogen Assimilation and Growth of Trifolium subterraneum L. Using Dinitrogen or Ammonium Nitrate

The relative effects of water stress on growth parameters of subterranean clover (Trifolium subterraneum L. cv. Woogenellup) dependent on either N₂ or 8 millimolar NH₄NO₃ for N were examined. Whole-plant carbon exchange rate (CER), acetylene reduction (AR), dry matter production, and Kjeldahl N accumulation were measured on uniform, intact swards of clover that were maintained under adequately watered conditions or were subjected to three cycles of water stress (leaf water potential ≤−30 bar) over an 18-day period. In the absence or presence of water stress, growth rate, net N accumulation rate, and total N concentration of plants dependent on N₂ were 25 to 26, 45 to 50, and 20 to 21% less, respectively, than plants supplied with 8 millimolar NH₄NO₃. The water stress treatment produced less than a 50% decrease in CER regardless of plant N source, a 90% inhibition of AR in plants dependent on N₂, and a 41% decline in dry matter production on both N sources. Water stress decreased reduced N accumulation 55% in N₂-dependent plants and 50% in NH₄NO₃-dependent plants. Changes in growth and N accumulation caused a 10 to 11% decrease in total plant N concentration of water-stressed plants compared to adequately irrigated controls, but water stress decreased the N concentration of tissue synthesized during the 18-day treatment period in N₂-grown plants more than in plants supplied 8 millimolar NH₄NO₃. Thus, the relative effect of water stress on growth under the two N regimes was similar, but N accumulation by N₂-dependent clover was inhibited to a slightly greater extent (P ≤ 0.001) than in NH₄NO₃-dependent plants.     

Feedback Regulation of Nitrate Influx in Barley Roots by Nitrate,Nitrite, and Ammonium

The short-lived radiotracer 13N was used to study feedback regulation of nitrate influx through the inducible high-affinity transport system of barley (Hordeum vulgare L. cv Steptoe) roots. Both wild-type plants and the mutant line Az12:Az70 (genotype nar1a;nar7w), which is deficient in the NADH-specific and NAD(P)H-bispecific nitrate reductases (R.L. Warner, R.C. Huffaker [1989] Plant Physiol 91: 947-953) showed strong feedback inhibition of nitrate influx within approximately 5 d of exposure to 100 fmu]M nitrate. The result with the mutant, in which the flux of nitrogen into reduced products is greatly reduced, indicated that nitrate itself was capable of exercising feedback regulation upon its own influx. This conclusion was supported by the observation that feedback in wild-type plants occurred in both the presence and absence of L-methionine sulfoximine, an inhibitor of ammonium assimilation. Nitrite and ammonium were also found to be capable of exerting feedback inhibition upon nitrate influx, although it was not determined whether these ions themselves or subsequent metabolites were responsible for the effect. It is suggested that feed-back regulation of nitrate influx is potentially mediated through several nitrogen pools, including that of nitrate itself.     

Comparison of the Effects of Root Temperature on Nitrate and Ammonium Nutrition of Oilseed Rape (Brassica napusL.) in Flowing Solution Culture: II. CATION-ANION BALANCE

Macduff, J. H., Hopper, M. J., Wild, A. and Trim, F. E. 1987.Comparison of the effects of root temperature on nitrate andammonium nutrition of oilseed rape (Brassica napusL.) in flowingsolution culture. II. Cation-anion balance.—J. exp. Bot.38: 1589-1602. The effects of root temperature and form of N nutrition (NH4or NOJ) on the mineral composition of the plant, the balanceof inorganic cation-anion uptake and on the apparent net effluxof H ⁺/OH^–ions from the roots were studied with 49-d-oldoilseed rape (Brassica napusL. cv. Bien venu) in flowing solutionculture. Plants were pre-treated for 14 d at a root temperatureof 5 °C prior to constant root temperatures of 3, 7, 11or 17°C for 14 d, with a common shoot temperature of 20/15°Cday/night. Nitrogen was supplied as NH⁺₄4 or NO^–₃ at 10mmol m³. Values of Q₁₀ (7-17°C) for mean unit absorptionrates of all the major nutrient ions (K⁺ , Mg⁺⁺ , NH⁺₄, SO₄,H₂PO₄, NO₃), except Ca⁺⁺, were > 2.0 over the first 5 d oftreatment but thereafter were < 1.5; the apparent effectof temperature on uptake rates diminished with time. Under NH⁺₄nutrition, inorganic cation uptake (Mg^{+ +} + K⁺+Ca^{+ +} +NH⁺₄)exceeded inorganic anion uptake (SO4 ^–₄+ H₂PO₄) over 14d at all temperatures, with the proportion of cation uptakeas NH4 remaining constant (0.67-0-68) irrespective of root temperature.The net efflux of H ⁺ from the roots approximately balancedNH⁺₄ uptake (1:1) over 14 d at each temperature and also balancedthe difference between the total uptake of inorganic cationsand inorganic anions. Under NO₃ nutrition, the sum of the netefflux of OH and the change in the carboxylate contents of plantsover 14 d approximately balanced the sum of NO₃ and SO ^–₄reduced in the plant. The majority of the negative charge associatedwith the reduction of NO₃ and SO ^–₄ was apparently effluxedas OH, but this fraction was lower at low root temperatures.The results are discussed in terms of mechanisms that have beenproposed to regulate the internal pH of plants. Key words: Brassica napus, oilseed rape, root temperature, cation-anion balance, H⁺/OH efflux.     

铵态氮和硝态氮营养与大豆幼苗的抗氰呼吸作用

在植物体内,NO云还原成NHI是一个耗能很多的生化过程,每还原一个NO。大约要消耗15个ATP分子（Salsac等1987）。植物直接吸收和利用NHi＋,可以减少能量消耗,所节约的能量可用于植物的生长。因此,从理论上讲,供NHI的植株要比供NOt的植株能够获得更高的生物产量。然而,对于大多数植物,供NOS的植株常具有更大的生长量和产量。对于这种现象,过去人们一直在矿物质和有机物积累的差异（Robin和Salsac1985）、根际的酸化程度（Ruftv等1983,Tolley－Henry和Rapen1986）、NHt有害浓度的积累（Haynes和Goh1978）、对光合作用的…