Photodegradation of fenitrothion and parathion in tomato epicuticular waxes

Photodegradation of (14)C-labeled fenitrothion ([O,O-dimethyl O-(3-methyl-4-nitrophenyl) phosphorothioate]) and parathion ([O,O-diethyl O-(4-nitrophenyl) phosphorothioate]) was conducted on a series of solid surfaces including isolated tomato fruit and leaf cuticle waxes. The wax-coated glass plate gave the comparative degradation of fenitrothion observed for the intact plant but both surfaces of octadecyl-capped silica gel and poly(tetrafluoroethylene) enhanced its volatilization. Photoinduced desulfuration and ester cleavage were common to both pesticides in waxes, but formation of the azo derivative was found to be a major degradation pathway characteristic of parathion. The modified electronic states of the nitro group by introduction of m-methyl group accounted for this different photoreactivity based on molecular orbital calculations.     

Formation and degradation of soil-bound [14C] fenitrothion residues in two agricultural soils

The formation of non-extractable residues of [¹⁴C]fenitrothion and their degradation in a black earth and a red yellow podzolic soil was studied. After a 65-day incubation, non-extractable radioactivity represented 73.7 and 59.35% of the applied radioactivity in the black earth and podzolic soil respectively, while evolved ¹⁴CO₂ accounted for only 9.4 and 12.7%. The effects of various amendments and treatments on the degradation of the non-extractable residues to ¹⁴CO₂ was studied. All of the amendments produced a priming effect and significantly increased the formation of ¹⁴CO₂ in both soils. The addition of unlabelled fenitrothion and 3-methyl-4-nitrophenol to the black earth and 3-methyl-4-nitrophenol to the podzolic soil produced the greatest increases in ¹⁴CO₂ evolution. The evidence presented suggests that a part of the unextractable residue is either fenitrothion or 3-methyl-4-nitrophenol.     

Field-incurred fenitrothion residues in kakis: comparison of individual fruits, composite samples, and peeled and cooked fruits

Field trials have been carried out to determine the variability of residue levels of fenitrothion and its main metabolites fenitrothion-oxon and 3-methyl-4-nitrophenol in individual kaki fruits versus composite samples, in peel versus flesh, and in whole uncooked versus whole cooked fruits. Residue levels have been determined by gas chromatography with thermionic specific detection after extraction with ethyl acetate and without further cleanup. At harvest, residue levels of fenitrothion were below maximum residue levels (MRLs) and the two metabolites 3-methyl-4-nitrophenol and fenitrothion-oxon could be quantified with average amounts of 0.080 and 0.012 mg/kg, respectively. Levels of fenitrothion decreased 88% after peeling, whereas temperature did not result in a high variation. The ratios of the highest residue level in the individual fruits to the corresponding mean of residue levels in the composite samples for fenitrothion were <3. This value is lower than that recommended by the World Health Organization as default value for consumer risk assessment.     

Functional characterization of enone oxidoreductases from strawberry and tomato fruit

Fragaria x ananassa enone oxidoreductase (FaEO), earlier putatively assigned as quinone oxidoreductase, is a ripening-induced, negatively auxin-regulated enzyme that catalyzes the formation of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), the key flavor compound in strawberry fruit by the reduction of the alpha,beta-unsaturated bond of the highly reactive precursor 4-hydroxy-5-methyl-2-methylene-3(2H)-furanone (HMMF). Here we show that recombinant FaEO does not reduce the double bond of straight-chain 2-alkenals or 2-alkenones but rather hydrogenates previously unknown HMMF derivatives substituted at the methylene functional group. The furanones were prepared from 4-hydroxy-5-methyl-3(2H)-furanone with a number of aldehydes and a ketone. The kinetic data for the newly synthesized aroma-active substrates and products are similar to the values obtained for an enone oxidoreductase from Arabidopsis thaliana catalyzing the alpha,beta-hydrogenation of 2-alkenals. HMMF, the substrate of FaEO that is formed during strawberry fruit ripening, was also detected in tomato and pineapple fruit by HPLC-ESI-MSn and became 13C-labeled when d-[6-13C]-glucose was applied to the fruits, which suggested that a similar HDMF biosynthetic pathway occurs in the different plant species. With a database search (http://ted.bti.cornell.edu/ and http://genet.imb.uq.edu.au/Pineapple/), we identified a tomato and pineapple expressed sequence tag that shows significant homology to FaEO. Solanum lycopersicon EO (SlEO) was cloned from cDNA, and the protein was expressed in Escherichia coli and purified. Biochemical studies confirmed the involvement of SlEO in the biosynthesis of HDMF in tomato fruit.     

Rapid and sensitive determination of 4-nitrophenol, 3-methyl-4-nitrophenol, 4,6-dinitro-o-cresol, parathion-methyl, fenitrothion, and parathion-ethyl by liquid chromatography with electrochemical detection

Liquid chromatography with electrochemical detection has been used to determine various nitropesticides, DNOC, fenitrothion, and parathion (methyl and ethyl), and some of their main metabolites, 4-nitrophenol for parathion (methyl and ethyl) and 3-methyl-4-nitrophenol for fenitrothion, by using indirect detection. Analysis of them in river water samples has been performed without a preconcentration step. The recovery efficiencies of the tested compounds yielded values between 96 and 112% at the fortification level of 0.5 ppb in a river water sample, and their relative standard deviations were between 1 and 15%. The detection limits of these compounds ranged between 0.05 and 0.14 ppb.     

Salinity tolerance in tomato: Implications of potassium,calcium, and phosphorus

Abstract

The effect of salinity on the growth and yield of tomato plants and mineral composition of tomato leaves was studied. Five tomato (Lycopersicon esculentum Mill) cultivars, Pearson, Strain B, Montecarlo, Tropic, and Marikit, were grown in sand nutrient culture. The nutrient solutions applied consisted of a modified half‐strength Hoagland solution with 50 mM sodium chloride (NaCl), 3 mM potassium sulphate (K₂SO₄), 1.5 mM orthophosphoric acid (H₃PO₄), and 10 mM calcium sulphate (CaSO₄). Stem height and number of leaves of tomato plants were not found to be significantly different but leaf and stem dry weight were reduced significantly in plants irrigated with saline nutrient solution in contrast with control plants. The total yield was reduced in plants that received saline treatments, but there was no significant difference in fruit number and fruit set percentage. The fruit electrical conductivity and total soluble solids were increased in plants irrigated with saline nutrient solution. Fruit pH was not found to be significantly different among salinity treatments. Mineral composition of tomato leaves were increased by addition of potassium (K), phosphorus (P), and calcium (Ca) to the saline nutrient solution. The addition of K to the solution resulted in an increase in sodium (Na) leaf content. The amounts of K and magnesium (Mg) were not significantly different among salinity treatments. Calcium content was increased when CaSO₄ was added. Application of H₃PO₄ resulted in the highest amount of P in tomato leaves under saline conditions. The present study revealed that application of K, P, and Ca under saline conditions improved fruit electrical conductivity and total soluble solids. Sufficiency levels of the mineral nutrients K and P were obtained in tomato leaves when the appropriate nutrient was used in the saline solution.     

Enzyme-linked immunosorbent assay based on a polyclonal antibody for the detection of the insecticide fenitrothion. Evaluation of antiserum and application to the analysis of water samples.

For development of an indirect competitive enzyme-linked immunosorbent assay (ELISA) for the organophosphorus insecticide fenitrothion, the specificity of the antiserum R-3 generated with the bifunctional hapten, LysMNPA (2-[[[(3-methyl-4-nitrophenyl)oxy]methylcarbonyl]amino]-6-(2,4-dinitrophenyl)aminohexanoic acid) and the application to the residual analysis of some water samples were evaluated. At optimized ELISA conditions, the quantitative working range was from 1 to 39 ng/mL with a limit of detection of 0.3 ng/mL and an IC(50) value of 6 ng/mL. Cross-reactivity to structurally similar organophosphorus compounds and related chemicals was determined. The antiserum R-3 showed significant cross-reactivity with fenitrooxon and 3-methyl-4-nitrophenol, which have a 3-methyl-4-nitrophenoxy group as common structures, but showed relatively low cross-reactivity with other compounds. Each water sample (river water, tap water, purified water, and bottled water) had a matrix effect and was investigated by adding Tween 20 in the assay buffer. These four kinds of water samples were fortified with fenitrothion at several concentration levels and were directly analyzed with only dilution with an equal volume of antiserum solution. The mean recovery was 105.9%, and the mean coefficient of variation was 10.9%. The results suggested that the developed ELISA would be very suitable for a preliminary screening for fenitrothion in water samples at such low levels.     

Absorption, disposition, metabolism, and excretion of [3-(14)C]caffeic acid in rats

Male Sprague-Dawley rats ingested 140 × 10(6) dpm of [3-(14)C]trans-caffeic acid, and over the ensuing 72 h period, body tissues, plasma, urine, and feces were collected and the overall levels of radioactivity determined. Where sufficient radioactivity had accumulated, samples were analyzed by HPLC with online radioactivity and tandem mass spectrometric detection. Nine labeled compounds were identified, the substrate and its cis isomer, 3'-O- and 4'-O-sulfates and glucuronides of caffeic acid, 4'-O-sulfates and glucuronides of ferulic acid, and isoferulic acid-4'-O-sulfate. Four unidentified metabolites were also detected. After passing down the gastrointestinal tract, the majority of the radiolabeled metabolites were excreted in urine with minimal accumulation in plasma. Only relatively small amounts of an unidentified (14)C-labeled metabolite were expelled in feces. There was little or no accumulation of radioactivity in body tissues, including the brain. The overall recovery of radioactivity 72 h after ingestion of [3-(14)C]caffeic acid was ～80% of intake.     

岩棉短程栽培模式中营养液对番茄生长及果实品质的影响

为实现设施番茄短程栽培过程中营养液的高效供给及标准化管理,寻求短程栽培模式中最优的营养液供给方式,在兼光型植物工厂条件下,研究了营养液电导率值(electric conductivity,EC值)、灌溉频率对番茄植株形态和果实品质的影响.试验以岩棉为栽培基质,3水平EC值为2、4和6 dS/m,3水平灌溉频率为1、3和5次/d,采用全因子试验设计方法,进行9组处理.采用综合评价方法获取最佳的营养液EC值和灌溉频率,并对植株形态和果实品质指标进行数理统计分析.结果表明:营养液EC值和灌溉频率影响植株的株高、茎粗、叶数、叶面积、叶形指数和根面比,同时也影响果实的平均质量、可溶性固形物(soluble solids content)和果形指数.其中EC值对平均果实质量影响显著(P＜0.05),灌溉频率对叶面积和平均果实质量影响极显著(P＜0.01);试验因素的交互作用对茎粗和果形指数影响极显著(P＜0.01),对SSC影响显著(P＜0.05).EC值为4 dS/m,灌溉频率为5次/d的营养液灌溉方式能兼顾植株发育和果实品质良好,该灌溉方式下SSC与平均果实质量呈极显著负相关(P＜0.01).该研究可为设施短程栽培番茄优质高产提供指导依据.     

Uptake and transformation of pesticide metabolites by duckweed (Lemna gibba)

Uptake and transformation of 14C-labeled metabolites from several pesticides, 3-methyl-4-nitrophenol (1), 3,5-dichloroaniline (2), 3-phenoxybenzoic acid (3), (R,S)-2-(4-chlorophenyl)-3-methylbutanoic acid (4), and (1RS)-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (5), were examined by using duckweed (Lemna gibba) in Hoagland's medium. More uptake into duckweed from the exposure water at pH 7.0 was observed for non-ionized 1 and 2 than for 3-5 in an ionized form, and their hydrophobicity accounted for these differences. While carboxylic acids 4 and 5 were scarcely transformed in duckweed, 1-3 mainly underwent phase II conjugation with glucose for 1 and 2, malic acid for 3, glutamic acid for 2, and malonylglucose for 3, the chemical identities of which were confirmed by various spectrometric analyses (LC-MS, LC-MS/MS, and NMR) and/or HPLC cochromatography with reference synthetic standards.     

Gas exchange,water relations,and Ion concentrations of salt‐stressed tomato and melon plants

Abstract

Tomato and melon plants were grown in a greenhouse and irrigated with nutrient solution having an EC of 2 dS m^?1 (control treatment) and 4, 6, and 8 dS m^?1, produced by adding NaCl to the control nutrient solution. After 84 days, leaf water relations, gas exchange parameters, and ion concentrations, as well as plant growth, were measured. Melon plants showed a greater reduction in shoot weight and leaf area than tomato at the two highest salinity levels used (6 and 8 dS m^?1). Net photosynthesis (Pn) in melon plants tended to be lower than in tomato, for all saline treatments tested. Pn was reduced by 32% in melon plants grown in nutrient solution having an EC of 4 dS m^?1, relative to control plants, and no further decline occurred at higher EC levels. In tomato plants, the Pn decline occurred at EC of 6 dS m^?1, and no further reduction was detected at EC of 8 dS m^?1. The significant reductions in Pn corresponded to similar leaf Cl^? concentrations (around 409 mmol kg^?1 dry weight) in both plant species. Net Pn and stomatal conductance were linearly correlated in both tomato and melon plants, Pn being more sensitive to changes in stomatal conductance (g_s) in melon than in tomato leaves. The decline in the growth parameters caused by salinity in melon and tomato plants was influenced by other factors in addition to reduction in Pn rates. Melon leaves accumulated larger amounts of Cl^? than tomato, which caused a greater reduction in growth and a reduction in Pn at lower salinity levels than in tomato plants. These facts indicate that tomato is more salt‐tolerant than melon.     

NH4+-N部分代替NO3--N对番茄生育中后期氮代谢相关酶活性的影响

采用砂培实验研究NH4 -N部分代替NO3--N对番茄的影响,结果表明:与全硝处理(100%NO3-)相比较,增铵处理(NH4 ∶NO3-=25%∶75%)下番茄鲜果重显著提高;同时叶片内NO3--N含量随增铵而显著降低,叶片与果实内NH4 -N含量及果实的可溶性蛋白含量随增铵而升高;增铵条件抑制了叶片和果实的硝酸还原酶(NR)活性,提高了叶片和果实的磷酸烯醇式丙酮酸羧化酶(PEPcase)活性及叶片谷氨酰胺合成酶(GS)活性,但对果实的谷氨酰胺合成酶(GS)活性影响不大。上述结果表明,NH4 -N部分代替NO3--N可增加番茄产量,提高集约化基地的生产量。     

Gas chromatographic method for determination of fenitrothion in technical and in emulsifiable concentrate and water-dispersible powder formulations: collaborative study

A variety of column packings and internal standards were evaluated to determine the most satisfactory system to use in a gas chromatographic (GC) method for analysis of fenitrothion, technical and formulations. Fenitrothion and the most closely related isomer, O,O-dimethyl O-(4-methyl-3-nitrophenyl) phosphorothioate, were resolved on columns packed with OV-210 and with polyphenyl ether, 6-ring (PPE-6R). A method based on the separation of fenitrothion on a PPE-6R column with fluoranthene as internal standard was selected for use in a limited collaborative trial and later for use in a full-scale collaborative trial with 21 collaborators participating. Each collaborator was furnished matched pairs of samples of technical fenitrothion, emulsifiable concentrate, and water-dispersible powder. The coefficients of variation (CV) for the paired samples were 1.02, 1.11, and 1.01, respectively, for technical fenitrothion, emulsifiable concentrates, and water-dispersible powders. Data are also presented for an alternative method in which compounds are separated on an OV-210 column with dibutyl sebacate as the internal standard. The method has been adopted official first action.     

MITIGATION EFFECTS OF SILICON ON TOMATO PLANTS BEARING FRUIT GROWN AT HIGH BORON LEVELS

Interactive effects of silicon (Si) and high boron (B) on growth and yield of tomato (Lycopercison esculentum cv. ‘191 F1’) plants were studied. Treatments were: 1) control (B1), normal nutrient solution including 0.5 mg L^?1 B (boron), 2) B1 +Si treatment: 0.5 mg L^?1 boron plus 2 mM Si, 3) B2 treatment: 3.5 mg L^?1 B, 4) B2 +Si treatment: 3.5 mg L^?1 B plus 2 mM Si, 5) B3 treatment: 6.5 mg L^?1 B, and 6) B3 +Si: 6.5 mg L^?1 B plus 2 mM Si. High B reduced dry matter, fruit yield and chlorophyll (Chl) in tomato plants compared to the control treatment, but increased the proline accumulation. Supplementary Si overcame the deleterious effects of high B on plant dry matter, fruit yield and chlorophyll concentrations. High B treatments increased the activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC. 1.11.1.7) and polyphenol oxidase (PPO; EC 1.10.3.1). However, supplementary Si in the nutrient solution containing high B reduced SOD and PPO activities in leaves, but POD activity remained unchanged. These data suggest that excess B-induced oxidative stress and alterations in the antioxidant enzymes. Boron (B) concentrations increased in leaves and roots in the elevated B treatment as compared to the control treatment. Concentrations of calcium (Ca) and potassium (K) were significantly lower in the leaves of plants grown at high B than those in the control plants. Supplementing the nutrient solution containing high B with 2 mM Si increased both nutrients in the leaves. These results indicate that supplementary Si can mitigate the adverse effects of high B on fruit yield and whole plant biomass in tomato plants.     

Effects of saline nutrient solutions on the growth and accumulation of mineral elements in some tomato cultivars

Abstract

Tomato cultivars were grown in a saline nutrient culture system to investigate growth and fruiting responses in relation to the application of 3 mM potassium (K), 1.5 mM phosphorus (P), and 10 mM calcium (Ca). The deleterious effects of salinity on tomato stem growth and fruit yield were ameliorated following the addition of K, P, and Ca to the nutrient solution. Potassium levels in tomato leaves were increased 4‐fold compared to control plants in the presence of applied K. The use of K resulted in an increase in Na content, however, a comparatively low level of sodium (Na) was obtained in treatments receiving K, Ca, and P. Calcium content was greater than sufficiency levels in all treatments, whereas magnesium (Mg) declined with the increase in salinity. The amount of P in tomato leaves was increased 4–5 fold when the nutrient solution was supplemented with 1.5 mM P. Correlation of vegetative parameters, such as stem height and leaf growth to salinity, revealed no significant responses, however commercial parameters such as total soluble solids and fruit weight correlated significantly with the saline nutrient treatments.     

Fertilization via carbonated water and mineral concentrations in a tomato crop

Abstract

In our experiments, application of carbonated water (CW) modified the nutritional status of a field‐grown tomato crop. Fruit concentrations of zinc (Zn), copper (Cu), iron (Fe), and manganese (Mn) were initially increased by CW, after which they were similar to the controls (Zn and Mn) or lower (Cu and Fe). Leaf concentrations of the same group of elements were also increased in the later growth stages. Calcium (Ca) and magnesium (Mg) in the earlier stages showed diminished concentrations in all plant parts in response to CW treatment; later on, a slightly higher Ca content was found in the fruit and lower in the leaves, while the fruit Mg content was decreased. Higher cation contents were found in the plant in response to the higher irrigation frequency and interaction with CW effect was detected in most of the cases. In the first period, leaf and fruit contents of all elements, except for Mg in the fruit were increased by daily irrigation. In the second one, leaf content of all nutrients was also increased; the fruit content of Mg, Ca and Zn was increased, while that of Cu, Fe, and Mn was decreased.     

Biotransformation of 3-methyl-4-nitrophenol, a main product of the insecticide fenitrothion, by Aspergillus niger

Biotransformation of the environmental pollutant 3-methyl-4-nitrophenol (MNP), a newly characterized estrogenic chemical, and the primary breakdown product of the heavily used insecticide fenitrothion was investigated using a common soil fungus. In 96 h, daily culture sacrifice, extraction, and analysis showed that the filamentous fungus, Aspergillus niger VKM F-1119, removed more than 85% of the MNP present in solution (original concentration = 25 mg/L), mostly through biodegradation. Additionally, in 16-day time-course studies, A. niger was capable of biotransformation of MNP at concentrations as high as 70 mg/L. Gas chromatography mass spectroscopy (MS) analyses of culture fluid extracts indicated the formation of four metabolites: 2-methyl-1,4-benzenediol, 4-amino-3-methylphenol, and two singly hydroxylated derivatives of MNP. Culture scale up and metabolite analysis by liquid chromatography MS resulted in the confirmation of the original metabolites plus the detection of an azo derivative metabolite that has not been previously reported before during MNP biodegradation by any micro-organisms.     

Effects of nitrogen form,nighttime nutrient solution strength,and cultivar on greenhouse tomato production

Higher greenhouse tomato (Lycopersicon esculentum Mill.) yield is obtained by using 25% of NH₄‐N in solution compared to using NO₃‐N as the sole nitrogen (N) source. However, blossom‐end rot (BER) may occur in tomato fruit when NH₄‐N was present in nutrient solutions. High nutrient solution strengths improve tomato fruit quality, but can also increase BER. Two NH₄‐N concentrations in solution (0 and 25%), and two nighttime solution strengths (NSS) (1X and 4X Steiner solution strength applied at 7 p.m.) were used to grow five indeterminate type greenhouse tomato cultivars: Caruso, Jumbo, Match, Max, and Trust. A significant interaction occurred between NH₄‐N concentration and NSS factors: 0% NH₄‐N and high NSS increased marketable yield and fruit:whole plant ratio, and reduced BER. In contrast, a concentration of 25% NH₄‐N and high NSS reduced marketable yield and the fruit:whole plant ratio, and increased BER incidence. Max, Match, and Trust tomato cultivars produced high marketable yield and high dry weight of stem and leaves, but were susceptible to BER. Use of NH₄‐N in solution reduced vegetative growth, and high NSS increased stem and leaf dry weight of the tomato plants. Fruit firmness was greater for the Max cultivar, and was unaffected by NH₄‐N and NSS at the mature green, breaker, and red ripe fruit development stages. However, at the fully ripe stage, fruit firmness was higher with high NSS and with 25% NH₄‐N.     

生殖生长期弱光对番茄表型特征和果实品质的影响

在人工光型植物工厂中以番茄品种“丰收74-560 RZ F1”为试材,分别在花期、果实膨大期、转色期、采收期进行160μmol·m⁻²·s⁻¹的弱光处理,非处理的生殖生长期光强度均保持在1000μmol·m⁻²·s⁻¹,通过番茄生长和果实品质指标评估不同生殖生长期弱光对番茄的影响。结果表明：（1）花期或膨大期弱光处理对番茄植株形态结构影响较大,其中花期弱光处理下的番茄植株徒长趋势最突出,且平均单株叶片数和节数最少,较对照分别减少了3.5个和1.6个;膨大期弱光处理后番茄叶片叶绿素a/b值及类胡萝卜素含量较其他处理显著降低;花期弱光处理后单株第一果穗坐果数较对照降低了53%,其他发育期弱光处理后坐果数均未受到显著影响;花期或膨大期弱光处理后平均单株第一、二、三果穗产量均显著低于其他发育期弱光处理;（2）与对照相比,各发育期弱光处理导致番茄第一穗果实可溶性固形物含量均出现不同程度的降低,其中花期降低25%,转色期弱光处理后番茄果实可溶性糖含量较对照降低15%,但总酸含量提高了26%,导致该处理下番茄果实糖酸比最低;与对照相比,所有发育期弱光处理后果实维生素C含量均有所降低,以采收期弱光处理后番茄果实维生素C含量最低。研究表明弱光导致番茄产量和品质降低,且不同生殖阶段番茄对弱光的敏感性有所差异。根据不同时期番茄生长特性及其对弱光的响应特点进行针对性补光对设施番茄稳质稳产具有一定的意义。     

Enhancement of salinity tolerance in tomato: Implications of potassium and calcium in flowering and yield

Abstract

Five tomato (Lycopersicon esculentum Mill) cultivars were grown in sand nutrient culture experiment in a greenhouse to investigate the effects of salinity on growth and yield. Nutrient solutions were made saline with 50 mM NaCl (EC = 5.5 mS/cm or supplemented with 2 mM KNO₃ (EC = 6.8), 20 mM Ca(NO₃)₂ (EC = 7.5), and combination of potassium (K) and calcium (Ca) (EC = 8.0). Seedlings were irrigated with saline treatments commencing two weeks after transplanting. Determination of sodium (Na) and K in tomato leaves and fruits were by flame photometry. Accumulation of Na in tomato fruits was higher than in leaves under control or saline conditions for all tomato cultivars. The amount of K in the tomato leaves was higher in control than in saline‐grown plants. Addition of K and Ca to the nutrient solution resulted in a 3 to 7 fold increase in K accumulation in all cultivars tested. Stem and leaf growth were significantly reduced with salinity but growth was enhanced following irrigation when K was added to the nutrient solution. Flowering and fruit set were adversely affected by NaCl stress. Reduction of flower number was 44% relative to the control plants. Fresh fruit yield decreased by 78% when plants received 50 mM NaCl. Growth and development of tomatoes under saline conditions was enhanced in this study following the application of K to the saline nutrient solution. Amelioration in growth was also achieved when Ca was used but to a lesser extent. Our results suggest that ion accumulation and regulation of K and Ca contribute to salt tolerance and growth enhancement.