Effects Of NaCl Stress Research Articles

Salt stress-induced seedling growth inhibition coincides with differential distribution of serotonin and melatonin in sunflower seedling roots and cotyledons.

Indoleamines regulate a variety of physiological functions during the growth, morphogenesis and stress-induced responses in plants. Present investigations report the effect of NaCl stress on endogenous serotonin and melatonin accumulation and their differential spatial distribution in sunflower (Helianthus annuus) seedling roots and cotyledons using HPLC and immunohistochemical techniques, respectively. Exogenous serotonin and melatonin treatments lead to variable effect on hypocotyl elongation and root growth under NaCl stress. NaCl stress for 48 h increases endogenous serotonin and melatonin content in roots and cotyledons, thus indicating their involvement in salt-induced long distance signaling from roots to cotyledons. Salt stress-induced accumulation of serotonin and melatonin exhibits differential distribution in the vascular bundles and cortex in the differentiating zones of the primary roots, suggesting their compartmentalization in the growing region of roots. Serotonin and melatonin accumulation in oil body rich cells of salt-treated seedling cotyledons correlates with longer retention of oil bodies in the cotyledons. Present investigations indicate the possible role of serotonin and melatonin in regulating root growth during salt stress in sunflower. Effect of exogenous serotonin and melatonin treatments (15 μM) on sunflower seedlings grown in the absence or presence of 120 mM NaCl substantiates their role on seedling growth. Auxin and serotonin biosynthesis are coupled to the common precursor tryptophan. Salt stress-induced root growth inhibition, thus pertains to partial impairment of auxin functions caused by increased serotonin biosynthesis. In seedling cotyledons, NaCl stress modulates the activity of N-acetylserotonin O-methyltransferase (HIOMT; EC 2.1.1.4), the enzyme responsible for melatonin biosynthesis from N-acetylserotonin.

Effects of NaCl stress on the growth and photosynthetic characteristics of Ulmus pumila L. seedlings in sand culture

The effects of NaCl stress on the growth and photosynthetic characters of Ulmus pumila L. seedlings were investigated under sand culture condition. With increasing NaCl concentration, main stem height, branch number, leaf number, and leaf area declined, while Na+ content and the Na+/K+ ratio in both expanded and expanding leaves increased. Na+ content was significantly higher in expanded leaves than in those just expanding. Chlorophyll (Chl) a and Chl b contents declined as NaCl concentration increased. The net photosynthetic rate, intercellular CO2 concentration, stomatal conductance, and transpiration rate also declined, but stomatal limitation value increased as NaCl concentration increased. Both the maximal quantum yield of PSII photochemistry and the effective quantum yield of PSII photochemistry declined as NaCl concentration rose. These results suggest that the accumulation of Na+ in already expanded leaves might reduce damage to the expanding leaves and help U. pumila endure high salinity. The reduced photosynthesis in response to salt stress was mainly caused by stomatal limitation.

Effect of NaCl stress on dihaploid tobacco lines tolerant to Potato virus Y

Salinity is an important abiotic factor that limits plant growth and development. The influence of salt stress induced by sodium chloride on plant growth, proline content, level of lipid peroxidation and activities of antioxidative enzymes was studied in F1 hybrid DH10 and four dihaploid lines (207B, 238C, 239K, 244B) of tobacco (Nicotiana tabacum L.). Dihaploids were obtained from anther-derived haploids of hybrid DH10 and were previously proved to be tolerant to Potato virus Y (PVY). In our study, plants were grown in vitro and exposed to NaCl (100 and 200 mM) for 33 days. All dihaploids and hybrid DH10 showed reduced growth after NaCl treatment. They accumulated significant amounts of sodium and proline in response to salt stress as have already been observed in tobacco and other plant species. In tobacco exposed to NaCl the lipid peroxidation level did not increase and activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase and catalase (CAT) mostly did not change significantly. The exception was line 239K where salt induced higher activities of SOD, CAT and POD. Two (238C and 244B) out of four dihaploids appeared more susceptible to salt stress as they showed weak growth in correlation with high proline and sodium content. Therefore, it seems that salt tolerance is not associated with tolerance to PVY. Variations in malondialdehyde and proline content as well as in enzymes activities observed among tobacco lines imply that dihaploids have different genetic properties which might result in different sensitivity to NaCl.

Calcium regulating growth and GABA metabolism pathways in germinating soybean (Glycine max L.) under NaCl stress

Effects of calcium on soybean growth and gamma-aminobutyric acid (GABA) accumulation pathways in germinating soybean were investigated. The harmful effect of NaCl stress was alleviated by CaCl2 while was aggravated by LaCl3. Glutamate decarboxylase (GAD) activity increased significantly under NaCl plus CaCl2 treatment, while its gene expression levels had no significant changes compared with NaCl treatment. GAD and diamine oxidase (DAO) activities and their gene expression levels significantly decreased after LaCl3 was applied. When treated with AG, the soybean growth was suppressed and DAO activity was inhibited completely while DAO expression had no significant changes. Meanwhile, the GABA content decreased by 17.04 and 11.76 % in cotyledon and embryo under NaCl plus CaCl2 treatment compared with NaCl treatment, respectively. It can be concluded that CaCl2 addition changed the contribution ratio of GABA shunt and polyamine degradation pathway for GABA formation, and the increment of GABA in germinating soybean was mainly synthesized via GABA shunt.

Presoaking application of propolis and maize grain extracts alleviates salinity stress in common bean (Phaseolus vulgaris L.)

Presoaking application of propolis extract (PE) or maize grain extract (MGE) for bean seeds to improve their germination and growth under 100mM NaCl stress was investigated. The potential effects of these extracts on seed germination, seedling growth, dehydration tolerance, antioxidant system and the concentrations of some osmoprotectant molecules and phytohormones were evaluated. PE or MGE alleviated the adverse effects of NaCl-stress to varying degrees. Despite the preference for MGE, soaking seeds in either extract, prior to germination and growth under NaCl-salinity, increased the seed germination percentage, seedling growth, the cell membrane stability index, the relative water content, the concentrations of free proline, total free amino acids, total soluble sugars, indole-3-acetic acid (IAA) and gibberellic acid (GA3), and the activity of the antioxidant system, while it reduced lipid peroxidation, electrolyte leakage and abscisic acid (ABA) compared to soaking seeds in distilled water. These results are important as the potential of MGE or PE to alleviate the harmful effects of NaCl stress offers an opportunity to increase the resistance of common bean plants to growth under saline conditions.

Effects of NaCl stress on accumulation of K+, Na+, Cl-, NO3 -,sugar and proline contents in the seedlings of Triticale-I

NaCl stress at 50 - 150 mM NaCl caused a 12 - 16-fold increase in Na+ accumulation in the root and 3 - 10-fold in the shoot of Triticale-I with a concomitant decrease in that of K+ and Cl- . NaCl stress increased the accumulation of reducing, total sugars and proline both in the root and shoot of the seedlings. The mechanism of salt tolerance of Triticale-I plants with respect to ionic relation and accumulation of sugars and proline were discussed. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18019 Bangladesh J. Bot. 42(2): 189-194, 2013 (December)

Putrescine Plays a Positive Role in Salt-Tolerance Mechanisms by Reducing Oxidative Damage in Roots of Vegetable Soybean

Polyamines play important roles in plant tolerance to environmental stress. With the aim of investigating the possible involvement of putrescine (Put) in salt-tolerance mechanisms in vegetable soybean roots, exogenous Put (10 mmol L−1) and its biosynthetic inhibitor D-arginine (D-Arg) (0.5 mmol L−1) were added to nutrient solution when vegetable soybean (Glycine max L. cv. Huning 95-1) seedlings were exposed to 100 mmol L−1 sodium chloride (NaCl). The results showed that Put ameliorated but D-Arg aggravated the detrimental effects of NaCl on plant growth and biomass production. Under NaCl stress, levels of free, soluble conjugated and insoluble bound types of Put in roots of vegetable soybean were reduced, whereas those of free, soluble conjugated, and insoluble bound types of spermidine (Spd) and spermine (Spm) were increased. Exogenous Put eliminated the decrease in Put but promoted the increase of Spd and Spm. However, these changes could be reversed by D-Arg. Under NaCl stress, activities of arginine decarboxylase (ADC), S-adenosylmethionine decarboxylase (SAMDC), diamine oxidase (DAO), and polyamine oxidase (PAO) were induced, with exogenous Put promoting and D-Arg reversing these changes. Furthermore, NaCl stress decreased activities of antioxidant enzymes. Exogenous Put alleviated but D-Arg exaggerated these effects of NaCl stress, resulting in the same changes in membrane damage and reactive oxygen species (ROS) production. These results indicated that Put plays a positive role in vegetable soybean roots by activating antioxidant enzymes and thereby attenuating oxidative damage.

NaCl stress and supplemental CaCl2 regulating GABA metabolism pathways in germinating soybean

Effects of NaCl stress and supplemental CaCl2 on soybean growth and gamma-aminobutyric acid (GABA) accumulation pathways in germinating soybean were investigated. Germinating under NaCl stress, GABA accumulation was caused not only by the activation of glutamate decarboxylase (GAD), diamine oxidase (DAO) and aminoaldehyde dehydrogenase (AMADH) existing in seed but also by their gene expression up-regulation during germination. However, after CaCl2 (6 mM) application, the harmful effect of NaCl stress (50 mM) was removed. GAD activity significantly increased, while its gene expression levels had no significant changes with the control, indicating that the increment in GAD activity was caused by the stimulation of exogenous Ca2+. Meanwhile, GABA was still accumulated although DAO and AMADH activities and their gene expression levels had no significant difference compared with the control. It can be concluded that CaCl2 addition decreased the contribution of polyamine degradation pathway to GABA accumulation compared with NaCl stress, and the increased GABA was mainly synthesized via GABA shunt.

Alleviation of abiotic salt stress in Ochradenus baccatus (Del.) by Trichoderma hamatum (Bonord.) Bainier

The current study was taken up to examine the role of bioagent (Trichoderma hamatum) in mitigating the deleterious effects of NaCl stress in Ochradenus baccatus. Varying concentrations of salt (0, 75, and 150 mM) were used to observe the effect on growth, pigments, some key metabolic attributes, antioxidant enzymes, and elemental accumulation in O. baccatus. The results indicated significant decrease in seed germination, plant growth, pigment content, membrane stability index, tissue water content, and total lipid content with salt stress. Lipid peroxidation increases with the increasing concentration of NaCl. Moreover, salinity stimulated the biosynthesis of phenols, diacylglycerol, sterol esters, nonesterified fatty acids, and enzymatic antioxidants like superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase. The Na+ content in shoot increases with elevated levels of NaCl concentration, accompanied with significant decreases in K+, Mg2+, and Ca2+. Application of bioagent (T. hamatum) has been observed to alleviate the antagonistic effect of salt stress on plant growth and metabolic processes. In absence and presence of salt stress, the bioagent stimulated the plant growth and alter the plant metabolism through the modification of the above parameters.

Pre-soaking in 24-epibrassinolide or salicylic acid improves seed germination, seedling growth, and anti-oxidant capacity in Phaseolus vulgaris L. grown under NaCl stress

SummaryThe effects of soaking common bean (Phaseolus vulgaris L.) seeds in 5.0 µM 24-epibrassinolide (EBL) or in 1.0 mM salicylic acid (SA) on seed germination and seedling growth, drought tolerance, osmoprotectant molecule concentrations, and anti-oxidant systems when grown under 100 mM NaCl stress were investigated. EBL or SA alleviated the adverse effects of NaCl-stress to varying degrees. Despite the preference for EBL, soaking seeds in either compound increased the seed germination percentage, seedling growth, the cell membrane stability index, the relative water content, osmoprotectant concentrations, and the activity of the anti-oxidant system, while it reduced lipid peroxidation and electrolyte leakage compared to control seeds soaked in distilled water. These findings are important as the potential of EBL or SA to alleviate the harmful effects of NaCl stress offers an opportunity to increase the resistance of common bean plants to growth under saline conditions.

外源SA和NO对NaCl胁迫下番茄幼苗生长、光合及离子分布的影响

以番茄（<em>Lycopersicon esculentum</em> Mill.）品种‘秦丰保冠’为试材，采用营养液培养法，研究单独和复配施用外源水杨酸（SA）、一氧化氮（NO）供体硝普钠（SNP）对100mmol/L NaCl胁迫下番茄幼苗生长、光合及离子分布的影响。结果表明：（1）单独和复配外施SA、SNP均能有效抑制NaCl胁迫下番茄幼苗叶片光合色素（Chla、Chlb、Chla+b和Car）含量、Chla/b值、净光合速率（<em>P</em>_n）、蒸腾速率（<em>T</em>_r）、气孔导度（<em>G</em>_s）、瞬时水分利用效率（WUE_t）、表观光能利用效率（LUE_app）和表观CO₂利用效率（CUE_app）的下降及Car/Chla+b值和胞间CO₂浓度（<em>C</em>_i）的升高，并以SA 和SNP复配处理效果最明显。（2）NaCl胁迫下，外源SA、SNP单独和复配处理的番茄幼苗各器官（叶、茎和根）中Cl^-、Na⁺含量和Na⁺/K⁺、Na⁺/Ca²⁺、Na⁺/Mg²⁺值显著降低，而K⁺、Ca²⁺和Mg²⁺的含量却不同程度提高，其中以SA 和SNP复配处理效果最好。（3）单独和复配外施SA、SNP均能有效减轻NaCl胁迫对番茄幼苗生长的抑制作用，并促进各器官生物量的积累和壮苗的形成，且以SA 和SNP复配处理效果更佳。研究表明，复配外施SA和SNP在诱导番茄幼苗提高抗（耐）盐能力方面具有协同增效作用。

Effect of NaCl stress on health-promoting compounds and antioxidant activity in the sprouts of three broccoli cultivars

Health-promoting compounds, antioxidant and myrosinase activity in the sprouts of three broccoli cultivars under 40 mM, 80 mM and 160 mM NaCl were investigated. LangYan (LY) sprouts had the richest health-promoting compounds among the evaluated cultivars. Treatment of 40 mM and 80 mM NaCl significantly decreased the content of ascorbic acid and total phenolic as well as antioxidant activity, but did not affect glucoraphanin, sulforaphane and myrosinase activity compared to the control. However, 160 mM NaCl treatment significantly enhanced the level of total phenolic, glucoraphanin, sulforaphane, antioxidant and myrosinase activity, while significantly decreased ascorbic acid content. The results suggest that 160 mM NaCl treatment would enhance antioxidant activity and sulforaphane yield in broccoli sprouts. The health-promoting value of broccoli sprouts depends on plant genotype and could be affected by NaCl stress.

Effects of salinity on growth, membrane permeability and root hydraulic conductivity in three saltbush species

The species of the genus Atriplex have been introduced in West Asia and North Africa to determine their adaptability for use as fodder species. These halophytes are well adapted to extreme environmental conditions and may possess interesting properties for soil rehabilitation. The effect of NaCl stress on growth, water relation and mineral nutrition were investigated in three xero-halophyte species of Atriplex used for rehabilitation of arid steppe in Algeria. Atriplex halimus, Atriplex canescens and Atriplex nummularia, were cultivated in hydroponic conditions and treated with increasing doses of NaCl (0–300 mM). All species showed positive plant growth for low and moderate levels of salinity. A. halimus had higher dry weight production than A. nummularia and A. canescens in high salinity concentration. Increasing concentration of salinity induced decrease in chlorophyll content (Chl a and b) and root hydraulic conductivity (L0) in all species, especially in A. canescens. All three species showed marked increase in electrolyte leakage across the salinity gradient. In addition all species were able to accumulate a large quantity of sodium (Na), chloride (Cl) and proline and to maintain higher relative water content, which was probably associated with a greater capacity for osmotic adjustment, whereas potassium (K) and calcium (Ca) decreased with increase salinity. The data suggest that salt tolerance strategies in all Atriplex species could involve a delicate balance among ion accumulation, osmotic adjustment, production of osmotica and maintenance of relative water content and growth.

Effects of foliar applications of nitric oxide and salicylic acid on salt-induced changes in photosynthesis and antioxidative metabolism of cotton seedlings

Nitric oxide (NO) is a plant signaling compound known to mitigate key physiological processes and salicylic acid (SA) is considered to be a signaling molecule that plays a key role in growth, development, and defense responses in plants under stress conditions. This work investigated the effects of sodium nitroprusside (SNP, a donor of NO) and SA on salt-tolerance of cotton (Gossypium hirsutum L.) seedlings by examining growth, photosynthetic performance, total osmoregulation substance content, antioxidative enzymes and H+-ATPase enzyme subjected to 100 mM NaCl. Addition of 100 mM NaCl inhibited the growth and photosynthetic parameters of cotton seedlings, and dramatically increased the electrolyte leakage, the plant contents of proline, lipid peroxidation (malondialdehyde), hydrogen peroxide (H2O2) and Na. Furthermore, antioxidant enzyme activities were restrained. Foliar applications of 0.1 mM SNP or/and 0.1 mM SA led to increase in the growth rate and photosynthesis, including photosystem II, net photosynthetic rate and transpiration rate, improvement of reactive oxygen species-scavenging enzymes activities and reduction of H2O2 accumulation in cotton seedlings induced by NaCl. In addition, membrane transport and function were facilitated by decreasing leaf electrolyte leakage, improving ion absorption and activating the osmotic-regulated substances metabolic. Further investigation also showed that SNP and SA alleviated the inhibition of H+-ATPase in plasma membrane induced by NaCl. The present study showed that foliar application of SNP and SA alone mitigated the adverse effect of salinity, while the combined application proved to be even more effective in alleviating the adverse effects of NaCl stress.

Common bean (Phaseolus vulgaris L.) seedlings overcome NaCl stress as a result of presoaking in Moringa oleifera leaf extract

Bean seed soaking in Moringa oleifera leaf extract to overcome NaCl stress and its effect on growth, yield, osmoprotectants and antioxidant system of bean plants were investigated. Plants exposed to NaCl exhibited a significant decline in growth, yield, leaf photosynthetic pigments and K+ contents and K+/Na+ ratio, while showed a significant increase in the contents of osmoprotectants and Na+, and the activity of enzymatic and non-enzymatic antioxidants. However, the presoaking treatment improved growth, yield and antioxidant system, and detoxified the stress generated by 100mM NaCl. The combined treatment of NaCl+presoaking in Moringa oleifera leaf extract overcame the adverse effects of NaCl stress by the increase in the content of osmoprotectants, the activity of enzymatic and non-enzymatic antioxidants and the ratio of K+/Na+. Therefore, we recommend using Moringa oleifera leaf extract as a soaking solution for bean seeds before sowing in a saline soil.

Alleviating the adverse effects of NaCl stress in maize seedlings by pretreating seeds with salicylic acid and 24-epibrassinolide

The effects of bio-regulators salicylic acid (SA) and 24-epibrassinolide (EBL) as seed soaking treatment on the growth traits, content of photosynthetic pigments, proline, relative water content (RWC), electrolyte leakage percent (EC%), antioxidative enzymes and leaf anatomy of Zea mays L. seedlings grown under 60 or 120mM NaCl saline stress were studied. A greenhouse experiment was performed in a completely randomized design with nine treatments [control (treated with tap water); 60mM NaCl; 120mM NaCl; 10−4M SA; 60mM NaCl+10−4M SA; 120mM NaCl+10−4M SA; 10μM EBL; 60mM NaCl+10μMEBL or 120mM NaCl+10μM EBL] each with four replicates. The results indicated that NaCl stress significantly reduced plant growth traits, leaf photosynthetic pigment, soluble sugars, RWC%, and activities of catalase (CAT), peroxidase (POX) as well as leaf anatomy. However, the application of SA or EBL mitigated the toxic effects of NaCl stress on maize seedlings and considerably improved growth traits, photosynthetic pigments, proline, RWC%, CAT and POX enzyme activities as well as leaf anatomy. This study highlights the potential ameliorative effects of SA or EBL in mitigating the phytotoxicity of NaCl stress in seeds and growing seedlings.

Molecular cloning and the expression of the Na+/H+antiporter in the monocot halophyte Leptochloa fusca (L.) Kunth

The plant vacuolar Na+/H+ antiporter plays an important role in salt tolerance. A vacuolar Na+/H+ cDNA (LfNHX1) gene was cloned from Leptochloa fusca(L.) Kunth, a halophyte forage grass, by cDNA and RACE methods using degenerate primers. The results show that the LfNHX sequence contains 2452 nucleotides and an open-reading frame of1620 nucleotides that encode a protein of 540 amino acids with a deduced molecular mass of 59.8kDa. The deduced amino acid contains the consensus amiloride-binding domain. The effects of NaCl stress on the Na+/ H+ gene expression were analysed using Real Time PCR. The analysis showed that the expression level of LfNHX1 increases in response to different levels of NaCl, indicating that V-Na+/H+ plays an important role in salt tolerance in this plant.

Differential responses of CO2 assimilation, carbohydrate allocation and gene expression to NaCl stress in perennial ryegrass with different salt tolerance.

Little is known about the effects of NaCl stress on perennial ryegrass (Lolium perenne L.) photosynthesis and carbohydrate flux. The objective of this study was to understand the carbohydrate metabolism and identify the gene expression affected by salinity stress. Seventy-four days old seedlings of two perennial ryegrass accessions (salt-sensitive ‘PI 538976’ and salt-tolerant ‘Overdrive’) were subjected to three levels of salinity stress for 5 days. Turf quality in all tissues (leaves, stems and roots) of both grass accessions negatively and significantly correlated with GFS (Glu+Fru+Suc) content, except for ‘Overdrive’ stems. Relative growth rate (RGR) in leaves negatively and significantly correlated with GFS content in ‘Overdrive’ (P<0.01) and ‘PI 538976’ (P<0.05) under salt stress. ‘Overdrive’ had higher CO2 assimilation and Fv/Fm than ‘PI 538976’. Intercellular CO2 concentration, however, was higher in ‘PI 538976’ treated with 400 mM NaCl relative to that with 200 mM NaCl. GFS content negatively and significantly correlated with RGR in ‘Overdrive’ and ‘PI 538976’ leaves and in ‘PI 538976’ stems and roots under salt stress. In leaves, carbohydrate allocation negatively and significantly correlated with RGR (r2 = 0.83, P<0.01) and turf quality (r2 = 0.88, P<0.01) in salt-tolerant ‘Overdrive’, however, the opposite trend for salt-sensitive ‘PI 538976’ (r2 = 0.71, P<0.05 for RGR; r2 = 0.62, P>0.05 for turf quality). A greater up-regulation in the expression of SPS, SS, SI, 6-SFT gene was observed in ‘Overdrive’ than ‘PI 538976’. A higher level of SPS and SS expression in leaves was found in ‘PI 538976’ relative to ‘Overdrive’. Accumulation of hexoses in roots, stems and leaves can induce a feedback repression to photosynthesis in salt-stressed perennial ryegrass and the salt tolerance may be changed with the carbohydrate allocation in leaves and stems.

Lupine embryo axes under salinity stress. II. Mitochondrial proteome response.

Germination is the first step of plant growth in plant life cycle. An embryonic radicle protruding the seed coat is the first part of plant which has direct contact with external environment including salt-affected soil. In embryo axes, mitochondria are the main energy producer. To understand better salinity impact on mitochondria functioning, this study was focused on the effect of NaCl stress onto mitochondria proteome. Mitochondria were isolated from yellow lupine (Lupine luteus L. ‘Mister’) embryo axes cultured in vitro for 12 h with 250 and 500 mM NaCl. Two-dimensional gel electrophoresis of mitochondrial proteins isolated from NaCl-treated axes demonstrated significant changes in proteins abundances as a response to salinity treatment. Twenty-one spots showing significant changes in protein expression profiles both under 250 and 500 mM NaCl treatment were selected for tandem mass spectrometry identification. This approach revealed proteins associated with different metabolic processes that represent enzymes of tricarboxylic acid cycle, mitochondrial electron transport chain, enzymes and proteins involved in mitochondria biogenesis and stresses response. Among proteins involved in mitochondria biogenesis, mitochondrial import inner membrane translocase, subunit Tim17/22, mitochondrial-processing peptidase subunit alpha-1, mitochondrial elongation factor Tu and chaperonins CPN60 were revealed. Finally, formate dehydrogenase 1 was found to accumulate in lupine embryo axes mitochondria under salinity. The functions of identified proteins are discussed in relation to salinity stress response, including salinity-induced PCD.Electronic supplementary materialThe online version of this article (doi:10.1007/s11738-013-1273-2) contains supplementary material, which is available to authorized users.

The effects of NaCl stress on Jatropha cotyledon growth and nitrogen metabolism

The effects of treatment with 50 and 100 mM NaCl on cotyledon growth, nitrogen assimilation, and the activities of key nitrogen metabolism enzymes were investigated in developing Jatropha curcas cotyledons. Growth inhibition was observed, and relative water content in the developing cotyledons significantly decreased in the 100 mM NaCl treatment. Lower levels of NO3-, NO2-, and NH4+ in the cotyledons were recorded when they were supplied with 50 and 100 mM NaCl. Nitrate reductase activities decline by 9.5% to 31.8% with respect to the control groups. Salt treatment also led to a marked decrease in nitrite reductase activity compared with the controls. Glutamine synthase, glutamate synthetase and dehydrogenase, alanine aminotransferase (AlaAT) and aspartate aminotransferase (AspAT) were markedly induced by the addition of NaCl. These findings will be useful for elucidating the roles key enzymes involved in nitrogen assimilation pathway of J. curcas plant.