Effects of nitrogen availability and supplementary light on the nitrate content of soil-grown lettuce

Summary

The effect of nitrogen availability and low level supplementary light on the growth and nitrate content of butterhead lettuce (Lactuca sativa var. capitata L.) grown in soil under greenhouse conditions in winter was studied. No significant interactions between nitrogen availability and supplementary light on yield, nitrate content, osmotic potential of expressed leaf sap and component osmotica were found. Supplementary light greatly increased plant growth and resulted in earlier harvest. When harvested with similar fresh weights, plant nitrate content was significantly reduced by supplementary light although the effect was slight. The reduced contribution of nitrate to sap osmotic potential at the higher light level was accompanied by a significant increase in the contribution of sucrose. While plant fresh weight was unaffected by the rate of nitrogen application, a positive correlation between nitrate content and nitrogen application rate was found. Reduced nitrate content at low nitrogen application rates was accompanied by increased contributions of chloride, glucose and sucrose to sap osmotic potential.     

应用BaPS技术研究双氰胺及硫对苹果园土壤尿素的硝化抑制效应

 在大田条件下应用气压过程分离法（BaPS）研究了双氰胺（DCD）和双氰胺与硫配合施用（DCD + S）对苹果园土壤氮素的硝化抑制效应。结果表明：施肥后40 d内,N + DCD和N + DCD + S处理的土壤NH₄⁺-N含量均高于N处理（对照）。N + DCD处理在6 ~ 20 d显著高于N处理;N + DCD + S处理直到30 d时仍显著高于N处理,比只施DCD的处理硝化抑制作用延长了10 d。两个添加硝化抑制剂处理土壤NO₃^--N含量显著低于N处理,降幅达18.72% ~ 58.91%。与N处理（对照）相比,N + DCD和N + DCD + S处理明显降低了土壤总硝化速率和反硝化速率,试验前期差异最大,进一步证实了硝化抑制剂可以有效地抑制NH4+-N向NO₃^--N的转化。     

Japanese holly growth and release pattern of ammonium and nitrate from controlled-release fertilizers

Applications of 0.85, 1.70 or 2.55 kg N m^?3 were made to Ilex crenata Thunb. Hetzi. Nitrogen sources included weekly applications of liquid fertilizer (NH₄NO₃) and single application of TVA's Sulfur coated urea (SCUT), Gold N (SCUG), Nitroform (NITR), isobutylidene diurea (IBDU), and an experimental N-containing Osmocote (OSCN). Shoot dry matter and leaf N from recently matured leaves were determined. Analyses of NH₄-N and NO₃-N were also conducted on the monthly leachates collected from the containers. Most controlled-release fertilizers (CRFs) produced greater dry weights at 1.70 kg N, while NH₄NO₃ produced more dry weight than CRF's at 0.85 or 2.55 kg N. Initially, for CRF's ammonium was more abundant than nitrate in the leachate; subsequently, nitrate became the dominant N form for most of the growing-season. All urea-based fertilizers had higher NH₄ levels in the leachate when compared with NH₄NO₃-based fertilizers.     

Effects of ammonium sulphate and urea on NO3− and NO2− accumulation,nutrient contents and yield criteria in spinach

In this study, effects of ammonium sulphate (AS) and urea fertilizers on NO₃⁻ and NO₂⁻ accumulation, N, P, K, Ca, Mg, Fe, Cu, Zn, Mn contents and some yield criteria in spinach were investigated. Increments in nitrogen doses of AS and urea from 0 (control) to 150 kg N level ha⁻¹ increased NO₃⁻, NO₂⁻, total N contents and yield of spinach significantly, but usually decreased P, Zn and Mn contents. NO₃⁻ contents of spinach in 120 and 150 kg N ha⁻¹ of urea applications were higher than that of AS applications, while the NO₃⁻ contents of spinach in the lower application doses of AS were higher than that of urea applications. Increasing phosphorus availability in the higher doses of AS applications due to possibility of decreasing soil pH might be decrease NO₃⁻ accumulation in spinach by assimilating NO₃⁻ in protein form. NO₃⁻ and NO₂⁻ contents also gave the significant negative relationships with yield and P content in spinach. Decreasing micronutrient contents in spinach at the higher nitrogen doses might be due to dilution effect by increasing the plant biomass.     

尿素配施氯化铵对菜薹硝酸盐积累的影响

利用盆栽试验研究尿素配施不同比例的氯化铵对菜薹(菜心)硝酸盐积累的影响,结果表明:氯化铵能显著减少栽培基质中亚硝酸细菌的数量,抑制硝化作用的进行。尿素与氯化铵配合施用能显著降低菜心硝酸盐含量,降低效应随着配施氯化铵比例的增加而增加。     

双氰胺对无土栽培菜薹硝酸盐积累的影响

 研究了双氰胺对甘蔗渣基质培菜薹硝酸盐积累的影响。结果显示, 采收前20 d施用双氰胺的处理, 其基质中的NO ₃^-_-N含量比不施双氰胺处理的低, 而NH₄⁺-N含量较高; 双氰胺显著降低菜心硝酸盐含量, 而对产量无明显影响。     

Effects of source,rate, and frequency of N application on yield,marketable grades and rot incidence of sweet onion (Allium cepa L. cv. Granex-33)

In a field experiment in the 1988-89 season, fertilizer formulations of NH₄NO₃, Ca(NO₃)₂, NaNO₃, NaKNO₃, and KNO₃ as N sources were applied at 84 and 168 kg N ha^?1 to onion plots direct seeded in the fall. A second experiment in the 1990-91 season tested the same N sources, except KNO₃, at rates of 168 and 224 kg ha^?1. Application strategy involved both splitting the total amount of fertilizer over two periods of the growing season (October–December and January—April) and the application frequency. With medium and high application rates (168 and 224 kg ha^?1), NH₄NO₃, NaNO₃, and NaKNO₃, increased high-value jumbo and large onions (premium marketable grade). Increased premium grades was due to increased bulb size and weight. Only NH₄NO₃ and Ca (NO₃)₂ increased total onion weight when N rate was increased from 84 to 168 kg ha^?1. Less frequent applications of split amounts of 84 kg N ha^?1 reduced marketable weight in the 1988–89 season, but doubling the rate to 168 kg ha^?1 restored the higher yields. At 224 kg N ha^?1 in the 1990–91 season, differences in onion grades were more pronounced among the different N sources, and NH4 NO₃ was superior in producing jumbo and large size onions. High N rates (224 kg ha^?1) and more frequent applications of split portions also increased the weight of jumbo onions. Split applications, providing 33% of the total N in the first 12 weeks of the growth period plus three applications of 22% each in the second 12 week period, increased bulb size and maximized yield of premium marketable grades. Effect of N rate on onion rot was dependent on split methods of applying the N during early and late growth periods. However, reduction in onion rot by the split application strategy was dependent on N source. Bulb decay was highest with NH4NO₃ and least with Ca(NO₃)₂ and NaNO₃.     

Nickel supplementation effect on the growth,urease activity and urea and nitrate concentrations in lettuce supplied with different nitrogen sources

Effect of nickel (Ni) in the nutrient solution on yield, N metabolism, and nitrate content of leafy vegetables is poorly understood. The aim of this nutrient solution culture experiment was to investigate the effects of Ni supplementation on the nitrogen (N) metabolism and growth of lettuce (Lactuca sativa L. cv. Baker) with either urea or nitrate as the N source. Nickel supplement at 0.04 μM reduced urea toxicity to the urea-fed plants. Addition of Ni to the nutrient solution significantly increased the leaves and root growth of the urea-fed lettuce plants while it increased the growth of lettuce plants fed with nitrate only at N level of 20 mM. At N level of 20 mM, the leaves fresh weight of the urea-fed plants promoted by Ni supplement was comparable with the nitrate-fed plants untreated with Ni. Nickel supplementation increased the leaf total N concentrations in the urea-fed plants, although the nitrate-fed plants accumulated greater N in their leaves compared with urea treated plants at without Ni treatment. Nickel addition decreased the concentrations of leaf urea-N in the urea-fed plants and NO₃-N in the nitrate-fed plants. Nickel addition enhanced urease activity in the leaves of urea-fed plants. The results indicated Ni supplementation enhances the growth of the urea-fed lettuce plants while it has role in decreasing leaf nitrate concentration and thus, improving the health quality of the nitrate-fed plants.     

The effect of nitrogen fertilization on plant growth and the nitrate content of leaves and roots of parsley in the Mediterranean region

Curly-leafed and turnip-rooted parsley have recently been introduced to Greece as alternative herbs within the programme for crop diversification. Because the response of these subspecies to nitrogen (N) application under the warm climatic conditions of the Mediterranean region is unknown, both were cultivated over three consecutive years in order to evaluate their yield potential and quality (in terms of nitrate content) in relation to nitrogen application in comparison with the traditionally cultivated plain-leafed subspecies. Nitrogen was applied as ammonium nitrate in the form of liquid feeds at rates of 30–450 mg kg⁻¹. Foliage and root yield increased with N application up to a level of 150 mg kg⁻¹ and the nitrate content of the tissues was low. Increasing N application rates to 300 or 450 mg kg⁻¹ did not cause a further increase in yield, but the nitrate content of the tissues increased. In view of health concerns with respect to human nitrate intake and environmental threats posed by excessive N application, it is concluded that the optimum level of ammonium nitrate application under local conditions should be 150 mg kg⁻¹. Overall, all three subspecies responded to N in a similar way in terms of yield and nitrate content.     

不同形态氮素营养对大白菜芝麻状斑点病发生的影响

 选择高感“大白菜芝麻状斑点病”品系03B9大白菜为试材,调查不同形态氮素营养对其发病的影响;并选择高抗品系C24、P8-1和高感品系03B9、P8-2为试材,在总氮素浓度为25 mmol · L-1,NO3- -N︰NH4+ -N分别为3︰7、5︰5和7︰3的水培条件下,研究氮代谢和抗氧化系统生理指标的变化。结果表明：铵态氮促进芝麻状斑点病发生的作用高于硝态氮和酰胺态氮。随铵态氮比例的增大,感病品系03B9和P8-2较抗病品系病斑数显著增多,叶柄中PPO活性和铵态氮、MDA含量及电导率升高,NR活性和多酚含量降低;抗病品系C24和P8-1叶柄中GDH活性和多酚含量升高,PPO活性、MDA含量及电导率变化不明显。推测营养液中铵态氮的比例增加,影响感病品系氮素代谢中有关酶类的活性,使体内铵态氮过量积累,导致细胞膜系统受到伤害,使液泡内的酚类物质与细胞质中的多酚氧化酶接触,引起褐变,在叶柄表面表现出芝麻斑点症状。     

不同铵硝配比对芥蓝伤流液组分及植株氮磷钾积累的影响

采用伤流液组分分析和植物营养分析的方法,探讨了不同铵硝配比（CK,0∶100;T1,10∶90;T2,25∶75;T3,50∶50）影响芥蓝生长的生理机制。结果表明：与全硝态氮营养液对照相比,3 个营养液增铵处理均提高了芥蓝植株的生物量和伤流强度,其中营养液增铵25%（T2）处理的效果最好。T1 处理芥蓝植株伤流液中蛋白态氮和P 的流量与CK 相比显著增加;T2 处理芥蓝植株伤流液中NO₃^--N、P、K 流量均为最高;T3 处理芥蓝植株伤流液中NH₄⁺-N、氨基酸态氮和蛋
白态氮流量最高,而NO₃^--N 和K 流量则显著低于CK。T1 处理和T2 处理显著提高了芥蓝植株N、P、K 的含量和积累量;T3 处理亦显著提高了芥蓝植株N、P 的含量和积累量,但显著降低了K 的含量和积累量。综合来看,营养液适量增铵（25%）处理的效果最好,可以提高芥蓝根系吸收能力,促进氮代谢,增加植株对N、P、K 的吸收和积累,从而促进植株生长。     

番茄根系分泌物、木质部和韧皮部汁液组分对矿质氮、有机氮营养的响应

 采用营养液培探讨了番茄幼苗根系参数、根系分泌物、木质部和韧皮部汁液组分对矿质氮（NH₄⁺-N、NO₃^--N）和有机氮（Glycine）的不同响应。结果表明,不同氮素处理8 d后,'申粉918'、'沪樱932'番茄根系干质量、根系体积表现为NO₃^--N > Gly-N > 对照 > NH₄⁺-N处理;而根系活力则表现为以供Gly-N 或NO₃^--N为最高,其次为供NH₄⁺-N的处理,以对照处理为最低。不同氮素形态显著影响不同番茄品种根系分泌物、木质部和韧皮部各组分含量。 NO₃^--N处理的番茄根系分泌物、木质部和韧皮部汁液中的NO₃^--N和P含量最高,供Gly-N、NH₄⁺-N其次,对照最低;而供Gly-N、NH₄⁺-N时铵态氮、游离氨基酸、可溶性糖含量一般均高于处理NO₃^--N和对照。番茄根际吸收不同氮素对根际pH亦产生不同的影响,吸收NO₃^--N和Gly-N后,根际pH显著升高,而吸收NH₄⁺-N后则降低。根系分泌物可溶性蛋白含量的变化表现为NO₃^--N > Gly-N > NH₄⁺-N> 对照,而木质部、韧皮部可溶性蛋白含量的变化则表现为Gly-N > NO₃^--N> NH₄⁺-N > 对照。番茄幼苗不同品种间的差异性表现,与氮素形态有关,以根系活力为指标的基因型差异在供应NO₃^--N、NH₄⁺-N和Gly-N及对照时,'沪樱932' 的根系活力均显著（P<0.05）大于 '申粉918'。     

Determination of the uptake and translocation of nitrogen applied at different growth stages of a melon crop (Cucumis melo L.) using N isotope

In order to establish a rational nitrogen (N) fertilisation and reduce groundwater contamination, a clearer understanding of the N distribution through the growing season and its dynamics inside the plant is crucial. In two successive years, a melon crop (Cucumis melo L. cv. Sancho) was grown under field conditions to determine the uptake of N fertiliser, applied by means of fertigation at different stages of plant growth, and to follow the translocation of N in the plant using ¹⁵N-labelled N. In 2006, two experiments were carried out. In the first experiment, labelled ¹⁵N fertiliser was supplied at the female-bloom stage and in the second, at the end of fruit ripening. Labelled ¹⁵N fertiliser was made from ¹⁵NH₄¹⁵NO₃ (10 at.% ¹⁵N) and 9.6 kg N ha⁻¹ were applied in each experiment over 6 days (1.6 kg N ha⁻¹ d⁻¹). In 2007, the ¹⁵N treatment consisted of applying 20.4 kg N ha⁻¹ as ¹⁵NH₄¹⁵NO₃ (10 at.% ¹⁵N) in the middle of fruit growth, over 6 days (3.4 kg N ha⁻¹ d⁻¹). In addition, 93 and 95 kg N ha⁻¹ were supplied daily by fertigation as ammonium nitrate in 2006 and 2007, respectively. The results obtained in 2006 suggest that the uptake of N derived from labelled fertiliser by the above-ground parts of the plants was not affected by the time of fertiliser application. At the female-flowering and fruit-ripening stages, the N content derived from ¹⁵N-labelled fertiliser was close to 0.435 g m⁻² (about 45% of the N applied), while in the middle of fruit growth it was 1.45 g m⁻² (71% of the N applied). The N application time affected the amount of N derived from labelled fertiliser that was translocated to the fruits. When the N was supplied later, the N translocation was lower, ranging between 54% at female flowering and 32% at the end of fruit ripening. Approximately 85% of the N translocated came from the leaf when the N was applied at female flowering or in the middle of fruit growth. This value decreased to 72% when the ¹⁵N application was at the end of fruit ripening. The ammonium nitrate became available to the plant between 2 and 2.5 weeks after its application. Although the leaf N uptake varied during the crop cycle, the N absorption rate in the whole plant was linear, suggesting that the melon crop could be fertilised with constant daily N amounts until 2–3 weeks before the last harvest.     

滇池北岸韭黄生产基地韭黄和韭菜产品硝酸盐含量及其积累规律

通过对滇池北岸韭黄生产基地52份韭黄和109份韭菜样品硝酸盐含量分析并结合田间试验,研究了韭黄硝酸盐累积规律以及光照、氮肥、硝化抑制剂（双氰胺和硫磺）对韭黄硝酸盐累积的影响。结果表明,韭黄硝酸盐含量为379.2～1 354.6 mg·kg^-1（均值774.1 mg·kg^-1）,而韭菜为258.2～3 878.0 mg·kg^-1（均值1 615.7 mg·kg^-1）。韭黄不同部位硝酸盐含量为：黄绿叶＞叶鞘＞叶片。早上6:00韭黄揭棚见光后,硝酸盐含量逐渐下降,12:00后又逐渐升高,下午2:00达最大,随后又下降。田间试验证实,减施20％的氮肥用量,韭黄硝酸盐含量下降13.6％,产量没有影响;双氰胺的施用使韭黄硝酸盐含量下降12.9％,并提高其产量11.1％;硫磺的施用可以增加韭黄产量13.5％,减少硝酸盐的含量8.6％。早上韭黄揭棚见光也能显著减少其硝酸盐含量。可见,上述措施能有效减少韭黄硝酸盐含量,具有推广价值。     

A rapid nitrate sap test for outdoor tomatoes

Trials were conducted with tomatoes over 2 years to evaluate nitrate sap testing and determine desirable sap nitrate values. In addition, desirable values for acetic acid extractable nitrate-N (HOAc-NO₃-N) and total N were determined. There were strong linear correlations between applied N and sap nitrate-N, HOAc-NO₃-N, and to a lesser extent with total N. The desirable sap nitrate value at 6 weeks from transplanting was 880–1180 mg 1^?1 in the first year and 980–1120 mg l^?1 in the second year. The sap nitrate desirable values were generally lower later in the crop growth. The desirable values found in this study for HOAc-NO₃-N and total N were in good agreement with other published data.     

硝态氮和铵态氮对观赏百合生长发育的影响

本文以西伯利亚百合为研究对象,从硝酸还原酶的活性,可溶性糖的含量,还原性糖的含量,可溶性蛋白质的含量,淀粉酶的活性等多个方面探究了不同氮水平的硝态氮和铵态氮对西伯利亚百合生长发育的影响.从结果看出,在观赏百合栽培过程中硝态氮和铵态氮合理的配比施用,既可使氮素被植物成分吸收利用,也避免了氮素积累所引起的负面效应.     

Fennel swollen base yield and quality as affected by variety and source of nitrogen fertilizer

Two fennel (Foeniculum vulgare Mill.) varieties, Dolce and Azoricum, were field grown for swollen base (SB) production to select the most productive variety and the most suitable source of N fertilizers in fields supplemented with cattle manure, calcium superphosphate and potassium sulfate. Plants were then grown either with or without one of the synthetic N fertilizers, ammonium sulfate (AS), ammonium nitrate (AN) or urea applied at a rate of 170 kg N ha⁻¹.Plants of var. Dolce were heavier in fresh weight and produced swollen bases (SBs) of 25% higher marketability percentage, 143% yield increase and 50% more oil content as compared to Azoricum. The increased SB yield and quality in var. Dolce were due to its lower bolting tendency as compared to var. Azoricum. Among all measured parameters, bolting tendency and SB oil content proved to be variety-dependent since both parameters showed no responses to N fertilizer source.When N was applied as a synthetic source, SB yield and quality were markedly reduced with about a 36% increase in SB nitrate content as compared to the control. The lowest SB yield and quality were obtained when AN or urea was used. Although AS produced a comparable yield to that of the control, the physical quality of the harvested SBs was adversely affected. The major compound in SB essential oil, trans-anethole, increased only with AN source in var. Dolce but fluctuated in var. Azoricum. The second most common compound, para-anis-aldehyde in var. Dolce or limonene in var. Azoricum, however, was markedly reduced with the application of any synthetic N source.It is suggested, therefore, that var. Dolce is more recommended for SB production than var. Azoricum. Fertilizing with synthetic N sources during plant growth and development is not advised when the soil has already been supplemented with organic nitrogen as not only are SB yield, quality and flavor reduced but also its safety for human consumption.     

Vine growth and nitrogen metabolism of ‘Fujiminori’ grapevines in response to root restriction

Two-year-old ‘Fujiminori’ grapevines (Vitis Venifera × V. Labrasca) planted in plastic pots (10 L) were used to evaluate vine growth and nitrogen metabolism in response to root restriction. Results show that root restriction reduced shoot growth and photosynthetic rate, but promoted root growth in vines. NO₃⁻-N concentration in all plant parts, and total N concentrations in brown roots and new leaves were decreased by root restriction, and chlorophyll and carotenoid concentrations in mature leaves were also reduced. Nitrate and nitrite reductase activities in brown roots and mature leaves were significantly reduced in root-restricted vines. The results suggest that the reduction of nitrate and nitrite reductase activities caused the inhibition of nitrogen assimilation, and this might be an important reason for root restriction inhibiting shoot growth.     

Effects of N fertilizers and rates on yield,safety and nutrients in processing spinach genotypes

Two field experiments were carried out at the Experimental Field, Department of Food Science (TE, Italy) in 2004 and 2005 to evaluate the effects of genotypes, different N forms and N rates on yield, safety and nutritional features of processing spinach. Experiment 1, as treatments, included spinach genotypes and N forms (CO(NH₂)₂; Agricote; NH₄NO₃); experiment 2 included three N forms (Ca(NO₃)₂; (NH₄)₂SO₄; NH₄NO₃) applied at rates of 0, 75, 150, 200 kg N ha⁻¹. This research work confirmed differences among spinach genotypes in terms of efficiency in N use and oxalate and nitrate accumulation. Spinach accumulated much more nitrate in petioles and much more oxalate in blades indicating that nitrate and oxalate might play a counterrole to each other. Fertilizers containing N under forms not readily available to the crop, i.e. Agricote, CO(NH₂)₂ and (NH₄)₂SO₄, increased nitrate and oxalate accumulations less than fast N-release fertilizers, but their effect on yield was limited. Highest yield with contents of nitrate and oxalate lower than the limits imposed to avoid health problems, were achieved with Ca(NO₃)₂, at rates of 130 and 150 kg N ha⁻¹ NH₄NO₃.     

Moderating water stress in tomato (Lycopersicon esculentum Mill.) plants by application of specific nitrogen doses

Summary

The effect of different doses of nitrogen on water stress in tomato (Lycopersicon esculentum Mill. ‘Royesta’) plants grown in a sandy soil and exposed, or not, to long-term water stress was studied. Nitrogen dose treatments consisted of Hoagland’s solution (N1 treatment), Hoagland’s solution + 40 mM NO₃^– (N2 treatment), or Hoagland’s solution + 80 mM NO₃^– (N3 treatment) applied every 3 d, for a total of seven applications following plant establishment. Subsequently, daily application of 80% (stressed) or 100% (unstressed) of the water evapotranspired by control plants the previous day was combined, factorially, with the three nitrogen treatments, for a period of 2 weeks. The leaf fresh weight (FW) at full turgor:leaf dry weight (DW) ratio was high in plants under the N1 and N3 stress treatments, with no significant difference between them soon after the start and at the end of the water stress treatment. However, the N2 treatment produced a significant increase in the ratio in well-watered plants, but not in water-stressed plants at the end of the stress period. The surface area per leaf was greater in stressed than in control plants, except for N2. Leaf water potential was greatly reduced in stressed N2 and N3 plants, but was unaltered in their well-watered counterparts. The significant increases in relative water content at the turgor loss point (around 3%) and in cell membrane rigidity (an increase of more than 125% in the bulk modulus of elasticity) clearly indicate an osmotic adjustment in stressed N2 plants, confirming that this N dose moderated the effects of the water stress imposed on N2 plants.