Stimulating and toxicity effects of nickel on growth,yield, and fruit quality of cucumber supplied with different nitrogen sources

Limited information is available on biological effects of various levels of nickel (Ni) (deficiency to toxicity levels) on growth and yield of certain crops, particularly vegetables. In this sand‐culture study, we investigated the effects of four levels of Ni (0, 50, 100, and 200 μM) on growth, yield, and fruit‐quality attributes of two cucumber cultivars (Cucumis sativus L. cvs. Super Dominus and Negin) supplied with urea or NH₄NO₃ as nitrogen source. Addition of 50 μM Ni to the nutrient solution resulted in a significant increase of shoot and root dry‐matter yield of cv. Negin although this increase was greater in the urea‐fed plants than those fed with NH₄NO₃. In both cultivars, addition of 50 μM Ni increased urease activity and thereby decreased the urea concentration in the urea treatment. Addition of 100 and 200 μM Ni caused a significant decrease in root and shoot growth of cucumber although this decrease was insignificant for cv. Super Dominus in the 100 μM treatment. The highest fruit yield, total soluble solids (TSS), and fruit firmness were achieved at the 50 μM Ni treatment. Regardless of nitrogen source, Ni addition proportional to the concentration used increased leaf Ni concentration and fruit acid ascorbic concentration. The concentration of Ni required for optimum growth and yield of cucumber varied with cultivars. The level of 50 μM was sufficient for optimum growth of cv. Negin in nutrient‐solution culture while lower concentration of Ni was required for cv. Super Dominus. While the beneficial effects of sufficient levels of Ni on growth and yield of urea‐fed plants was greater than with NH₄NO₃‐fed plants, the toxic effects of Ni in these plants were also greater.     

Influence of nitrogen forms and levels on the growth and nutrition of cacao

Ammonium and nitrate are the major forms of nitrogen (N) present in tropical soils. An experiment was conducted to assess the influence of nitrate and ammonium forms (NO₃^?, NH₄⁺, and mix of NO₃^? + NH₄⁺), and levels (1.5–12.0 mM) of N on the growth and nutrition of cacao (Theobroma cacao L). Growth parameters were significantly influenced by N forms, and nitrogen supplied as NH₄⁺ proved better for the growth of cacao compared with NO₃^? form and mixtures of these two forms. Irrespective of the forms of N, levels of N had no significant effect on plant growth parameters. Nutrient efficiency ratios (NERs) (shoot dry matter produced per unit of nutrient uptake) for macronutrients were sulfur>phosphorus>calcium>magnesium>nitrogen>potassium (S>P>Ca>Mg>N>K) and for micronutrients NERs were in the order of copper>boron>zinc>iron>manganese (Cu>B>Zn>Fe>Mn).     

Accumulation and partitioning of biomass and soluble carbohydrates in maize seedlings as affected by source of nitrogen,nitrogen concentration,and cultivar 1

Abstract

Seedlings of four maize hybrids were grown hydroponically to investigate the impact of different N sources (Ca(NO₃)₂, (NH₄)₂SO₄ and a 1:1 mixture of both) on (i) production and partitioning of root and shoot dry matter, (ii) concentration of soluble carbohydrates in roots and shoots and their partitioning to these plant parts, (iii) concentration of starch in the shoot, and (iv) N uptake. During the main phase of the experiments (duration 14d), the plants were grown in a greenhouse at 25/22°C day/night temperatures and a photoperiod of 16h. Nitrogen was supplied at three concentrations (2.8, 28, and 280 ppm). The root‐zone pH was 6.5. Under the lowest N supply, the N sources produced similar root and shoot dry matters. At the highest N level (280 ppm), NO₃‐fed plants were superior. In contrast, the mixture of NH₄ and NO₃ ^? was optimum at 28 ppm. More or less pronounced N form by N concentration interactions were also found in the concentration and distribution of soluble carbohydrates and in all remaing traits. There were almost statistically significant cultivar by N form interactions in shoot dry matter (P = 0.07) and total dry matter (P = 0.06), indicating the existence of considerable genotypic variation in sensivity to NH₄‐N.     

Ammonium reduces growth,fruit yield and fruit quality of watermelon

Watermelon (Citrullus lunatus Thunb.) plants cv ‘Sugar Baby’ were grown hydroponically in a greenhouse under NO₃:NH₄ ratios of 3:1, 1:1, and 1:3. Plants receiving the high ammonium treatment expressed symptoms of NH4‐toxicity and declined rapidly after bloom. Reducing NO₃:NH₄ from 3:1 to 1:1 significantly reduced growth, water use, fruit yield, flesh soluble solids and uptake of NO₃, NH₄, K, Ca and Mg.     

Potassium and nitrogen effects on carbohydrate and protein metabolism in alfalfa roots

An investigation was conducted to determine the effect of potassium (K) nutrition on alfalfa (Medicago sativa L.) growth and metabolism of root total nonstructural carbohydrates (TNC) and proteins, and to study whether nitrogen (N) fertilization overcomes N deficiency and low root protein concentrations caused by K deficiency. In Experiment 1, nodulated alfalfa plants were grown in plastic pots containing washed quartz sand and provided minus‐N Hoagland's solution containing 0, 0.6, or 6.0 mM K. Shoot and root K concentrations increased with increasing solution K. Root N concentrations were higher in plants receiving 6.0 mM K than in plants receiving 0.6 or 0 mM K, but shoot N concentrations were similar for all treatments. Plant persistence, shoots per plant, and shoot mass increased as solution K levels increased. Root starch concentration and utilization were positively associated with K nutrition. Total amylase activity was higher, but endoamylase activity was lower in roots of plants receiving 6.0 mM K compared to plants receiving 0.6 or 0 mM K. Root soluble protein concentrations were significantly higher in plants receiving 6.0 mM K than in plants receiving 0 or 0.6 mM K. In Experiment 2, plants were supplied with Hoagland's solution containing 10 mM N as ammonium (NH₄ ⁺) or nitrate (NO₃) with 0,3, or 6.0 mM K. The addition of N increased root N concentrations only in plants receiving 0 mM K. Plant persistence was reduced by NH₄ ⁺ application, especially in plants receiving 0 or 3 mM K. Root starch concentrations were markedly reduced in plants receiving NH₄ ⁺ at all K levels. The addition of NO₃ ^‐ had little effect on alfalfa root carbohydrate and protein metabolism and subsequent shoot growth. Potassium deficiency reduced starch and protein concentrations in roots; factors that were associated with poor persistence and slow shoot regrowth of alfalfa.     

Root morphology of maize under homogeneous or spatially separated supply of ammonium and nitrate at three concentration ratios

Maize (Zea mays L. cv. Anjou 256) seedlings were grown hydroponically for 10 d in a split‐root system (3mM N; pH 5.5) under either a homogeneous supply (HS) or a simultaneous, but spatially separated supply (SS) of NH₄ ⁺ andNO₃ ^‐. Treatments comprised three NH₄ ⁺:NO₃ ^‐ ratios (1:4, 1:1, 4:1). Shoot dry matter and various root traits (dry matter, number of laterals, length of main axes, total root length and total root surface area) were determined. For all NH₄ ⁺:NO₃ ^‐ ratios, shoot dry matter, root dry matter, total root length, and root surface area, were greater under HS than under SS. Under both SS and HS, increasing NH₄ ⁺:NO₃ ^‐ ratios resulted in decreased shoot and root dry matter production, but did not alter the shoot:root dry matter ratio. Under SS, root dry matter, root length, and root surface area was greater on the NO₃ ^‐‐fertilized side than on the NH₄ ⁺ ‐fertilized side. The allocation of root dry matter, root length, and root surface area to the NH₄ ⁺ or NO₃ ^‐ compartments was unaffected by changes in the NH₄ ⁺:NO₃ ^‐ ratio. Enhanced NH₄ ⁺ nutrition has detrimental effects on top growth, but roots are apparently unable to avoid excessive NH₄ ⁺ uptake by proliferating in zones where NO₃ ^‐ is the only form of N.     

Effect of N‐form on growth and nutrient content of creeping bentgrass 1

Abstract

The primary nitrogen forms utilized by plants are ammonium and nitrate. Although the importance of nutrients other than nitrogen for proper turfgrass growth is well established, the amounts of these nutrients in the plant tissue in relation to the use of different N‐forms has not been clearly documented. This study was conducted under greenhouse conditions to determine the effect of N‐form and cutting regime on growth, macronutrient, and micronutrient content of creeping bentgrass (Agrostis palustris Huds. ‘Penncross'). Treatments consisted of 100% NO3^? (calcium nitrate), 100% NH₄ ⁺ (ammonium sulfate), and a 50:50 ratio of NH₄ ⁺:NO₃ ^?. Half the turfgrass plants were maintained at a height of 1 cm (cut), while the other half of the plants were not cut until the end of the study (uncut). The uncut 50:50 treatment yielded the highest shoot, verdure, and total plant dry matter, while the uncut NO₃ ^? treatment produced the highest root dry matter. The uncut NH₄ ⁺ treatment yielded the least shoot, root, and total plant dry matter. Plants of the uncut NO₃ ^? treatment had greater accumulation of macronutrients in the shoot and root tissue compared to plants of the NH₄ ⁺ treatment. The uncut NO₃ ^? and 50:50 treatments had higher total accumulation of micronutrients compared to the uncut NH₄ ⁺‐treated plants. The cut NO₃ ^? treatment resulted in the highest macronutrient and micronutrient contents in the root tissue in comparison to other cut treatments. The cut treatments had the highest percentage accumulation of nutrients in the verdure tissue, while the uncut treatments had the highest percentage accumulation of nutrients in the shoot tissue.     

Tomato growth and nutrient uptake patterns as influenced by nitrogen form and light intensity 1

Tomato plants were grown in sand culture with NH₄ or NO₃ forms of N and at two levels of light. Plants were harvested at 0, 5, 9, or 12 days after starting treatments. NH₄‐N nutrition reduced growth, suppressed K, Ca, and Mg accumulation in shoot, increased P and N content and markedly reduced K, Ca, and Mg uptake per unit of root surface. Reduced light level decreased the toxic effects of NH₄ and markedly decreased NH₄ accumulation in shoots.     

Dry matter and nitrogen accumulation are not affected by superopt1mal concentration of ammonium in flowing solution culture with pH control

Abstract

While it is known that superoptimal concentrations of the nitrate (NO₃ ^?) ion in solution culture do not increase NO₃ ^? uptake or dry matter accumulation, the same is not known for the ammonium (NH₄ ⁺) ion. An experiment was conducted utilizing flowing solution culture with pH control to investigate the influence of superoptimal NH₄ ⁺ concentrations on dry matter, nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) accumulation by nonnodulated soybean plants. Increasing the NH₄ ⁺ concentration in solution from 1 to 10 mM did not affect dry matter or N accumulation. Accumulations of K, Ca, and Mg were slightly decreased with the increased NH₄ ⁺ concentration. The NH₄ ⁺ uptake system, which is saturated at less than 1 mM NH₄ ⁺, is able to regulate uptake of NH₄ ⁺ at concentrations as high as 10 mM.     

Tillering,nutrient accumulation,and yield of winter wheat as influenced by nitrogen form 1

When grown with mixtures of nitrate‐nitrogen (NO₃‐N) and ammonium‐nitrogen (NH₄‐N) (mixed N) spring wheat (Triticum aestivum L.) plants develop higher order tillers and produce more grain than when grown with only NO₃. Because similar work is lacking for winter wheat, the objective of this study was to examine the effect of N form on tillering, nutrient acquisition, partitioning, and yield of winter wheat. Plants of three cultivars were grown to maturity hydroponically with nutrient solutions containing N as either all NO₃, all NH₄, or an equal mixture of both forms. At maturity, plants were harvested; separated into shoots, roots, and grain; and each part analyzed for dry matter and chemical composition. While the three cultivars varied in all parameters, mixed N plants always produced more tillers (by a range of 16 to 35%), accumulated more N (28 to 61%), phosphorus (P) (22 to 80%), and potassium (K) (11 to 89%) and produced more grain (33 to 60%) than those grown with either form alone. Although mixed N‐induced yield increases were mainly the result of an increase in grain bearing tillers, there was cultivar specific variation in individual yield components (i.e., tiller number, kernels per tiller, and kernel weight) which responded to N form. The presence of NH₄ (either alone or in the mixed N treatment), increased the concentration of reduced N in the shoots, roots, and grain of all cultivars. The effect of NH₄ in either treatment on the concentrations of P and K was variable and depended on the cultivar and plant part. In most cases, partitioning of dry matter, P, and K to the root decreased when NH₄ was present, while partitioning of N was relatively unaffected. Changes in partitioning between the shoot and grain were affected by N treatment, but varied according to cultivar. Based on these data, the changes in partitioning induced by NH₄ and the additional macronutrient accumulation with mixed N are at least partially responsible for mixed‐N‐induced increases in tillering and yield of winter wheat.     

Effects of different nitrogen forms on potato growth and development

The objective of this study was to test if the effects of different nitrogen forms on potato growth depend on the plant growth stage. Plants from different potato cultivars were treated with different forms of nitrogen before tuber initiation and after tuber formation. A nitrification inhibitor was used to prevent the transformation of ammonium (NH₄⁺) to nitrate (NO₃^?). Plant growth, tuber formation, leaf area, leaf chlorophyll content, and tuber yield were assessed. The results obtained over 2 years indicate that plants treated with NO₃-nitrogen (N) before or at tuber initiation produced more tubers per plant than those treated with NH₄-N. However, plants treated with NH₄-N develop tubers earlier. Additionally, after tuber formation, plants treated with NH₄-N had better shoot growth than plants treated with NO₃-N. A larger leaf area with higher leaf chlorophyll content resulted in greater dry matter accumulation and higher tuber yield at harvest for plants treated with NH₄-N.     

Specific response of sugar beet cultivars to different nitrogen forms

Six cultivars of sugar beet characterized by different sugar contents were grown in water culture on Reid-York nutrient solution for 30 days. Nitrogen was included in the medium in the form of either NH₄NO₃, NH₄Cl or Ca(NO₃)₂ at the concentrations 105, 210 and 420 mg N/l. The results obtained reveal that both shoot dry weight and leaf area were dependent upon the type of cultivar and the form and concentration of nitrogen present in the nutrient solution. The least amount of shoot matter and the smallest leaf area were obtained in the presence of ammonium as the sole nitrogen source. The concentration of total nitrate and ammonium nitrogen measured in the shoot was found to be dependent on the cultivar type and on the concentration of nitrogen present in the nutrient solution. The highest oxalic acid concentrations were detected in plants grown on nitrate. No synthesis of oxalic acid was detected upon growth on ammonium as the sole nitrogen source.     

氮素不同形态配比对菠菜体内游离氨基酸含量和相关酶活性的影响

采用溶液培养试验,研究了氮素不同形态配比对菠菜茎叶中游离氨基酸含量及3种主要氮代谢酶活性的影响。结果表明:1)随着营养液中铵硝比(NH4+-N/NO3--N)的降低,菠菜茎叶中游离氨基酸的总量呈下降趋势。在全硝营养下(NH4+-N/NO3--N=0∶100)下,菠菜茎叶中游离氨基酸的总量只有全铵营养(NH4+-N/NO3--N=100∶0)的34.4%。2)在全铵营养下,菠菜茎叶中游离氨基酸的主要组分是谷氨酰胺、精氨酸和谷氨酸,三者占游离氨基酸总量的百分比依次为39.8%、20.2%和8.9%;在全硝营养下,菠菜茎叶中游离氨基酸以谷氨酸、天冬氨酸和丝氨酸为主,三者占游离氨基酸总量的百分比分别为30.3%1、8.6%和8.5%。3)提高营养液中硝态氮的比例,可以显着提高菠菜茎叶中硝酸还原酶(NR)的活性,同时降低了谷氨酸脱氢酶(GDH)的活性,谷氨酰胺合成酶(GS)活性则呈现先升后降的抛物线状变化规律。4)菠菜茎叶中NR活性与谷胺酰胺含量之间存在着显著负相关关系(r=-0.968)。     

Effect of nitrogen form during the flowering period on zucchini squash growth and nutrient element uptake

Zucchini squash (Cucurbita pepo L. cv. Green Magic) plants were grown hydroponically with nitrate (NO₃):ammonium (NH₄) ratio of 3:1 until the onset of flowering when the plants were assigned to four NO₃:NH₄ ratio (1:0, 1:1, 1:3, or 3:1) treatments. Changing the original nitrogen (N) form ratio significantly affected plant growth, fruit yield, nutrient element, and water uptake. Growth of plants was better when NO₃‐N (1:0) was the sole form of N than when NH₄‐N was part of the N treatment. Fruit yields for plants fertilized with 1:0 or 1:3 N‐form ratio were double those of plants grown continuously with 3:1 N ratio. The largest leaf area and plant water use were obtained with 1:0 N ratio treatment Total uptake of calcium (Ca), magnesium (Mg), and potassium (K) decreased with increasing NH₄‐N proportion in the nutrient solution which suggest NH₄‐N was competing with these cations for uptake. The results also demonstrated that growers may increase fruit yield by using a predominantly NO₃‐N source fertilizer through the vegetative growth stage and by shifting the NO₃:NH₄ ratio during the reproductive phase.     

氮肥对镉在土壤-芥菜系统中迁移转化的影响

以芥菜为研究对象, 采用盆栽试验, 探讨了不同用量的5种氮肥对污染农田土壤中镉(Cd)在土壤–根系–地上部迁移累积的影响。结果表明: 5种氮肥均促进了芥菜根系对Cd的吸收, 且根系Cd含量随施氮量的增加而增加; 但根系吸收转运Cd的能力随氮肥施用量的增加呈先降后增的变化趋势。在≤200 mg(N)·kg^-1(土)的施氮水平下, CO(NH₂)₂和Ca(NO₃)₂处理能显著降低芥菜地上部Cd含量, 降低幅度分别为13%~29%和24%~30%。在施氮量相同的条件下, NH₄Cl和(NH₄)₂SO₄显著降低了土壤pH, 增加了土壤DTPA-Cd含量, 促进了芥菜对Cd的吸收。本试验条件下, 200 mg(N)·kg^-1(土)的CO(NH₂)₂在增加芥菜产量和降低芥菜地上部Cd含量等方面优于其他氮肥处理。     

Plant Availability of Cadmium in Soils: II. Factors Related to the Extractability and Plant Uptake of Cadmium in Cultivated Soils

Abstract

Eighty four soil samples collected from southeastern Norway were analyzed for Cd by extraction with NH₄OAc, DTPA, NH₄OAc-EDTA, NH₄NO₃, HCl and CaCl₂. The total Cd, pH, exchangeable K and Ca, dithionite-extractable Mn, available P and fine sand (0.2–0.02 mm) contents were the principal factors related to the extractable Cd, with some inter-extractant variations. Cadmium extracted by NH₄NO₃, NH₄OAc, HCl and CaCl₂ decreased with increasing soil pH, but the Cd extracted by all the extractants increased with increasing total Cd, exchangeable K and Ca, available P, and Mn-oxide contents in the soils. The Cd concentrations in plants were significantly related to the extractable Cd, exchangeable Ca and Mg, pH, Mn-oxides and organic matter content.     

Fruit Quality and Nitrogen,Potassium, and Calcium Content of Apple as Influenced by Nitrate: Ammonium Ratios in Tree Nutrition

Evaluations of fruit quality and nitrogen, potassium, and calcium concentration of apple (Malus domestica Borkh. cvs. Gala and Golab) grown with five treatments of NO₃^?:NH₄⁺ ratios were made in pot culture. The concentrations of NO₃^?:NH₄⁺ ratios were 2.5:0.1, 6:1, 6:0.7, 6:0.5, 6:0.3 meq L^?1. Fruit size, percent dry matter, total dissolved solids, total acidity, or juice pH was not affected by increased ammonium in the ratio. Firmness decreased as the proportion of NH₄⁺ increased. Gala and Golab differed in some of these parameters. Concentrations of N and K increased as NH₄⁺ increased, whereas Ca had no trend or decreased. Generally, the treatment of 2.5:0.1 produced fruits with lower N but higher K and Ca concentrations than the other treatments. This research showed that some parameters such as fruit weight, length, and diameter, juice pH, and dry matter were not affected significantly by NH₄⁺ concentration whereas composition was affected.     

Characteristics of ammonium and nitrate fluxes along the roots of Picea asperata

Nitrogen (N), ammonium (NH₄⁺) and nitrate (NO₃^?), is one of the key determinants for plant growth. The interaction of both ions displays a significant effect on their uptake in some species. In the current study, net fluxes of NH₄⁺ and NO₃^? along the roots of Picea asperata were determined using a Non-invasive Micro-test Technology (NMT). Besides, we examined the interaction of NH₄⁺ and NO₃^? on the fluxes of both ions, and the plasma membrane (PM) H⁺-ATPases and nitrate reductase (NR) were taken into account as well. The results demonstrated that the maximal net NH₄⁺ and NO₃^? influxes were detected at 13–15?mm and 8–10.5?mm from the root apex, respectively. Net NH₄⁺ influx was significantly stimulated with the presence of NO₃^?, whereas NH₄⁺ exhibited a markedly negative effect on NO₃^? uptake in the roots of P. asperata. Also, our results indicated that PM H⁺-ATPases and NR play a key role in the control of N uptake.     

Alterations in the mineral nutrition of pea seedlings exposed to cadmium 1

A study was made of the effects of different levels of cadmium (Cd) in the nutrient solution (0.0, 1.5, and 6.0 mg/L Cd) on the assimilation of nitrate (NO₃ ^‐) and the uptake and distribution of cationic nutrients in pea (Pisum sativum cv. Argona) seedlings. Cadmium treatment resulted in an accumulation of NO₃ ^‐ in the root, indicating an alteration in NO₃ ^‐ translocation to the shoot. This was related to a decrease in the nitrate reductase (NR) activity in the shoot, severely inhibiting NO₃ ^‐ assimilation, and associated to a reduction in fresh tissue weight and in their relative water content. The concentration of potassium (K) decreased in both root and shoot, but its relative distribution between those tissues was not affected by the presence of Cd. Among other cationic nutrients, manganese (Mn) was the most affected, its concentration constantly decreased concomitantly with the increase in Cd supply. The distribution of Mn between shoot and root revealed that more was accumulated in the shoot than in the root, opposite to the distribution of NO₃ ^‐ The ‘shock’ addition of 6.0 mg/L Cd in a short‐term experiment confirmed that the transport of NO₃ ^‐ to the aerial part was reduced after 72 h of treatment and Cd displaced Mn from its physiological positions in root tissues.     

Nitrification and denitrification in an acidic soil of tea (Camellia sinensis L.) field estimated by δ15N values of leached nitrogen from the soil columns treated with ammonium nitrate in the presence or absence of a nitrification inhibitor and with slow-release fertilizers

Forty-two-day-old wheat (Triticum aestivum L. var. Asakazekomugi) plants were treated with complete, K-free (—K), Ca-limited (—Ca), and Mg-free (—Mg) nutrient solutions for 10 days using 2 mM NH₄NO₃ as the nitrogen source, which was replaced with 4 mM ¹⁵ NH₄C1 or Na¹⁵NO₃ for the subsequent 2 days to investigate the absorption, translocation, and assimilation of inorganic nitrogen in relation to the mineral supply. In another experiment plants were grown on NO₃ ^?, NH₄ ⁺, NH₄N0₃, and K-free and Ca-limited NH₄N0₃ nutrient solutions for 10 days, and then in the latter three treatments the nitrogen source was replaced with NO₃ ^? and half of the —K plants received K for 6 days to examine the changes in the nitrate reductase activity (NRA).

Wheat plants absorbed NH₄ ^?N and NO₃-N at a similar rate. Influence of K on the absorption of N0₃-N was stronger than that on the absorption of NH₄-N in wheat plants. The supply of K to the —K plants increased the absorption of NO₃-N, while the absorption of NH₄-N still remained at a lower rate in spite of the addition of K. A limited supply of Ca and lack of Mg in nutrient media slightly affected the absorption of NH₄-N. The influence of K was stronger on the translocation of nitrogen from roots to shoots, while Ca and Mg had little effect. When K was supplied again to the —K plants the translocation of NO₃,-N was more accelerated than that of NH₄-N. Incorporation of NH₄-N into protein was higher than that of NO₃-N in all the tissues; root, stem, and leaf. Assimilation of NH₄-N and NO₃-N decreased by the —K and —Mg treatments.

Leaf NRA of wheat plants decreased in the —K and —Ca plants. Higher leaf NRA was found when K was given again to the —K plants than when the plants were continuously grown in K-free media. Replacement of NO₃ ^? with NH₄ ⁺ as the nitrogen source caused a decline of leaf NRA, while the supply of both NH₄ ^?N and NO₃-N slightly affected the leaf NRA.