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The purpose of this study is to explore the physiological mechanisms underlying the attenuation of Cd toxicity using Se in two cherry tomato cultivars ‘Hanluzhe’ (HLZ) and ‘Lvfeicui’ (LFC), with low and high Cd accumulation rates, respectively. Hydroponic experiments were conducted and 2.5 μmol L−1 Se was applied to hydroponic solution with 50 μmol L−1 Cd. The photosynthetic parameter, antioxidant enzyme activities, non-enzymatic antioxidants, mineral elements, phytochelatins, and Cd contents of two cherry tomatoes were detected. Exogenous Se reduced Cd assimilation and altered its chemical form and subcellular distribution in both cultivars. Exogenous Se mitigated Cd-induced oxidative stress by enhancing the activity of superoxide dismutase (37.0% in HLZ and 48.9% in LFC), peroxidase (50.6% in HLZ and 30.4% in LFC), catalase (18.5% in HLZ and 28.6% in LFC), ascorbate peroxidase (26.6% in HLZ and 47.4% in LFC), and glutathione peroxidase (28.3% in HLZ and 30.4% in LFC). Although Se significantly increased the photosynthetic rate (Pn) of HLZ, it exhibited no significant effect on the Pn of LFC under Cd stress. Se improved the phytochelatin (15.1% in HLZ and 42.4% in LFC) content, which accelerated Cd chelation in both cultivars. Further, Se alleviated nutrient (Ca, Mg, Fe, Zn, and Cu) assimilation or transportation in both cultivars to varying degrees. The efficiency of Cd toxicity alleviation using Se was higher in the high Cd-accumulating cultivar LFC than in the low Cd-accumulating cultivar HLZ. Screening low Cd-accumulating cultivars with exogenous Se is a promising method to manage Cd accumulation in cherry tomatoes.

In recent times, the excessive accumulation of nitrate has been one of the main reasons for the secondary salinization of greenhouse soils. Light plays a key role in a plant’s growth, development, and response to stress. A low-red to far-red (R:FR) light ratio could enhance plant salinity tolerance, but the mechanism at a molecular level is unclear. Thus, we analyzed the transcriptome responses of tomato seedlings to calcium nitrate stress under either a low R:FR ratio (0.7) or normal light conditions. Under calcium nitrate stress, a low R:FR ratio enhanced both the antioxidant defense system and the rapid physiological accumulation of proline in tomato leaves, which promoted plant adaptability. Using weighted gene co-expression network analysis (WGCNA), three modules including 368 differentially expressed genes (DEGs) were determined to be significantly associated with these plant traits. Functional annotations showed that the responses of these DEGs to a low R:FR ratio under excessive nitrate stress were enriched in the areas of hormone signal transduction, amino acid biosynthesis, sulfide metabolism, and oxidoreductase activity. Furthermore, we identified important novel hub genes encoding certain proteins, including FBNs, SULTRs, and GATA-like transcription factor, which may play a vital role in low R:FR light-induced salt responses. These findings offer a new perspective on the mechanisms and environmental implications behind low R:FR ratio light-modulated tomato saline tolerance.

The purpose of this study is to determine the effects of selenium (Se) on cherry tomato fruits under cadmium (Cd) stress. Methods: Se (2.5 μM) was applied to hydroponic solution with different concentrations of Cd (10 μM and 50 μM). The yield, quality, mineral elements, and Cd contents of cherry tomato was determined. Ten micromolars of Cd had no effect on the appearance and quality of cherry tomato, while 50 μM Cd significantly reduced the content of vitamin C, lycopene, soluble solids, and soluble sugars in the fruits. Cd stress significantly reduced cherry tomato fruit yield and also inhibited the accumulation of mineral elements such as calcium, magnesium, and iron in the fruits, and these inhibitory effects increased with the increase of Cd concentration. Besides, Se application significantly increased fruit yield by 8.38% and 8.56% under 10 μM and 50 μM Cd stress, respectively, when compared with plants grown without Se. Exogenous application of Se also significantly increased vitamin C, lycopene, and soluble sugar contents of fruit under 50 μM Cd stress and effectively promoted the accumulation of calcium, iron, copper, and zinc in the fruits. In addition, Se significantly reduced the Cd contents in roots, stems, and leaves of cherry tomato plants under 10 μM and 50 μM Cd stress, thereby leading to 12.85% and 12.48% respective decrease in the Cd content in fruits when compared with plants grown without Se. Therefore, applying Se can effectively improve the yield and quality of cherry tomato fruits under Cd stress and also reduce the Cd content in fruits.

Chayote

The MADS-box gene plays an important role in plant growth and development. As an important vegetable of Cucurbitaceae, chayote has great edible and medicinal value. So far, there is little molecular research on chayote, and there are no reports on the MADS-box transcription factor of chayote. In this study, the MADS-box gene family of chayote was analyzed for the first time, and a total of 70 MADS-box genes were identified, including 14 type I and 56 type II MICK MADS genes. They were randomly distributed on 13 chromosomes except for chromosome 11. The light response element, hormone response element and abiotic stress response element were found in the promoter region of 70 MADS genes, indicating that the MADS gene can regulate the growth and development of chayote, resist abiotic stress, and participate in hormone response; GO and KEGG enrichment analysis also found that SeMADS genes were mainly enriched in biological regulation and signal regulation, which further proved the important role of MADS-box gene in plant growth and development. The results of collinearity showed that segmental duplication was the main driving force of MADS gene expansion in chayote. RNA-seq showed that the expression levels of SeMADS06, SeMADS13, SeMADS26, SeMADS28, SeMADS36 and SeMADS37 gradually increased with the growth of chayote, indicating that these genes may be related to the development of root tubers of ‘Tuershao’. The gene expression patterns showed that 12 SeMADS genes were specifically expressed in the male flower in ‘Tuershao’ and chayote. In addition, SeMADS03 and SeMADS52 may be involved in regulating the maturation of male flowers of ‘Tuershao’ and chayote. SeMADS21 may be the crucial gene in the development stage of the female flower of ‘Tuershao’. This study laid a theoretical foundation for the further study of the function of the MADS gene in chayote in the future.

Two pot experiments were conducted to study the effects of intercropping with cadmium (Cd) accumulator plant Eclipta prostrata and hyperaccumulator plant Crassocephalum crepidioides on the growth a...

Straw of Solanum photeinocarpum accessions originating from two climatic-ecological zones (Chengdu, in the Mountain-Central Subtropical-Cold Zone; and Ya’an, in the Central Subtropical-Long Spring ...

A pot experiment was conducted to investigate the growth, physiological changes and mechanism of drought resistance of Phedimus aizoon L. under different levels of water content .CK: 75% ~ 80% of the MWHC (maximum water holding capacity), Mild drought: 55% ~ 60%, Moderate drought: 40% ~ 45%, Severe drought: 20% ~ 25%.We observed that the plants grew normally in the first two treatments, even the mild drought promoted the growth of the roots. In the last two treatments, drought stress had a significant negative effect on plant growth, at the same time, Phedimus aizoon L. also made positive physiological response to cope with the drought: The aboveground part of the plant (leaf, plant height, stem diameter) was smaller, the waxy layer of the leaves was thickened, the stomata of the leaves were closed during the day, and only a few stomata were opened at night, which proved that the dark reaction cycle metabolism mode of the plant was transformed from C3 cycle to CAM pathway. The activity of antioxidant enzymes (SOD, POD and CAT) was continuously increased to alleviate the damage caused by drought. To ensure the relative stability of osmotic potential, the contents of osmoregulation substances such as proline, soluble sugar, soluble protein and trehalose increased correspondingly. But plants have limited regulatory power, with aggravation of drought stress degree and extension of stress time, the MDA content and electrolyte leakage of leaves increased continuously. Observed under electron microscope,the morphology of chloroplast and mitochondria changed and the membrane structure was destroyed. The plant's photosynthetic and respiratory mechanisms are destroyed and the plant gradually die.

Soil cadmium (Cd) contamination severely threatens human health. Therefore, screening and breeding low-Cd absorption cultivars of cherry tomato (Solanum lycopersicum L.) is essential to restrict human Cd intake. In this study, a hydroponic experiment was conducted to perform a comparative transcriptome analysis of the leaves of two cherry tomato cultivars with different Cd contents under different Cd stress (0, 10, and 50 μM), for the purpose of exploring the differences in the transcriptional responses to Cd stress between the two cultivars. Our results revealed that the Cd content in the leaves of HLZ (Hanluzhe; a low-Cd accumulation cultivar) was significantly lower than that in the leaves of LFC (Lvfeicui; a high-Cd accumulation cultivar). Transcriptome analysis showed that the different expression genes (DEGs) were mainly involved in plant hormone signal transduction, antioxidant enzymes, cell wall biosynthesis, and metal transportation. In the LFC leaves, DEGs in the IAA signal transduction and antioxidant enzymes exhibited higher transcription levels. However, the DEGs in the ETH signal transduction demonstrated a lower transcription level compared to that of HLZ. Over-expressed genes in the pectin biosynthesis and pectin methylesterase (PME) of the LFC leaves might result in the trapping of Cd by increased levels of low-methylated pectin around the cell wall. Furthermore, Cd transporter genes, such as HMA5, NRAMP6, CAX3, ABCC3, and PDR1, were up-regulated in the HLZ leaves, indicating that the HLZ cultivar comprised an active Cd transport capacity from apoplast to vacuolar. This may contribute to the low Cd concentration observed in the HLZ leaves. Overall, our study provides a molecular basis for tomato screening and breeding.

Phytoremediation technology has become one of the main techniques for remediating soils polluted by heavy metals because it does not damage the environment, but heavy metal-tolerant plants have the disadvantages of low biomass and slow growth. A pot experiment was conducted to study the effects of melatonin (Mel) on growth and cadmium (Cd) accumulation in the Cd accumulator Malachium aquaticum and hyperaccumulator Galinsoga parviflora by spraying different concentrations of Mel on them. The results showed that shoot biomass, photosynthetic pigment content and antioxidant enzyme activity were increased in both species after Mel was sprayed on their leaves. Mel reduced the Cd content in shoots of M. aquaticum and increased it in those of G. parviflora. In general, Cd accumulation was greatest in M. aquaticum when Mel was 200 μmol L-1 (120.71 μg plant-1, increased by 15.97% than control) and in G. parviflora when Mel was 100 μmol L-1 (132.40 μg plant-1, increased by 68.30% than control). Our results suggest it is feasible to improve the remediation efficiency of lightly Cd-contaminated soil by spraying G. parviflora with100 μmol L-1 Mel.

To mitigate greenhouse gas (GHG) emissions, different strategies have been proposed, including application of dolomite, crop straw and biochar, thus contributing to cope with the increasing global warming affecting the planet. In the current study, pristine wheat straw biochar (WBC) and magnesium (MgCl2.6H2O) modified wheat straw biochar (MWBC) were used. Treatments included control (CK), two WBC dosages (1% and 2.5%), and two MWBC doses (1% and 2.5%). After 90 days of incubation, WBC and MWBC improved the soil physiochemical properties, being more pronounced with increasing rates of biochar. MWBC2.5 significantly decreased microbial biomass carbon (MBC), while microbial biomass nitrogen (MBN) increased when both biochar materials (WBC1 and MWBC1) were applied at low rate. Compared to control soil, Urease and Alkaline phosphatase activities increased with the increasing rate of WBC and MWBC. The activities of dehydrogenase and β-glucosidase decreased with the WBC and MWBC application, compared to CK. The fluxes of all the three GHGs evaluated (CO2, CH4 and N2O) decreased with time for both biochar amendments, while cumulative emission of CO2 increased by 58% and 45% for WBC, and by 54% and 41% for MWBC, as compared to CK. The N2O cumulative emissions decreased by 18 and 34% for WBC, and by 25 and 41% for MWBC, compared to CK, whereas cumulative methane emission showed non-significant differences among all treatments. These findings indicate that Mg-modified wheat straw biochar would be an appropriate management strategy aiding to reduce GHG emissions and improving the physiochemical properties of affected soils, and specifically of the red dry land soil investigated in the current work.

In order to investigate the effect of different arbuscular mycorrhizal (AM) fungi on Cadmium (Cd) uptake of Sedum aizoon L.. Under Cd stress, five AM fungi (GMA, GM, GV, BEG167, BEG168) were inoculated to Sedum aizoon L. at 10 mg⋅kg−1 Cd concentration, and the growth, physiological indexes and Cd accumulation of Sedum aizoon L. under different treatments were measured. The results showed that: GMA fungi significantly increased the growth and biomass of Sedum aizoon L.; GMA and GM fungi significantly increased the proline content of Sedum aizoon L.; GMA and BEG168 fungi significantly reduced the Cd content of roots, stems and leaves. Therefore, under the Cd stress, inoculating GMA fungi can not only significantly improve the growth, biomass, but also significantly reduce the content of Cd in various parts of Sedum aizoon L., which has a certain value in practical production.

In this study, we added different Selenium (Se) concentrations (0 mg⋅kg−1, 2.5 mg⋅kg−1, 5.0 mg⋅kg−1, 10.0 mg⋅kg−1, 20.0 mg⋅kg−1) into soil to study the effect of Se on the growth, quality and Se content of Talinum paniculatum (Jacq.) Gaertn. The results show that different Se concentration has significant different influence on the growth of T. paniculatum. Low Se concentration can promote the growth of T. paniculatum, but high Se concentration would inhibit the growth of T. paniculatum. The chlorophyll content of T. paniculatum increased with the increase of Se concentration, which was beneficial to the photosynthesis of T. paniculatum. The Se content of T. paniculatum increased gradually with the increase of Se concentration, and the rule of Se content of T. paniculatum was root > leaf > stem. Taken together, the optimum concentration of Se in the soil of T. paniculatum cultivation was about 5.0∼10.0 mg⋅kg−1.

In this study, we used two tomato cultivars ‘Medium Vegetable 4’ and ‘Middle Mix 9’ as materials, applying Na2SeO3 to the soil to study the effect of external Selenium (Se) on the growth and Cadmium (Cd) accumulation under low temperature (18/12 °C, day/night) and low light (100 μmol⋅m−2⋅s−1). Results show that Se can significantly reduce the Cd accumulation in root, leaf and stem and promote the development of tomato under Cd stress. Under low temperature, Se can enhance cold tolerance through increasing the chlorophyll content, POD activity, soluble sugar and soluble protein content and decreasing the MAD content of two cultivars. Our study provides direction for tomato cultivation under low temperature and low light.

The dormant Sedum aizoon L.seedlings were treated with different days(1d, 3d, 5d and 7d) of low temperature (5°C), and restored to grow for 40d (25°C).The growth indexes, photosynthetic characteristics and carbohydrate metabolism indexes were measured to compare the dormancy relieving effects of the seedlings. The results showed that Sedum aizoon L. was physiologic dormancy, and the effect was the best when it was treated at 5°C for 5 days, and the dormancy was completely relieved.

In this study, light-emitting diode (LED) was used as light source to cultivate pakchoi in hydroponics. The effects of red light and far red light ratio (R: FR) of 0.7, 1.0 and 4.2(CK) on the growth and photosynthetic characteristics of pakchoi under different nitrate stress concentrations were studied. The results showed that the growth indexes, gas exchange parameters (except intercellular CO2 concentration) of pakchoi decreased significantly under excess nitrate stress. And the growth of pakchoi was more inhibited under high nitrate stress concentration. Under low R: FR ratio, the growth indexes and net photosynthetic rate of pakchoi increased significantly, while the intercellular CO2 concentration decreased significantly, and the effect was achieved when R:FR=0.7. Therefore, reducing R: FR ratio can alleviate the inhibition of excess nitrate stress on the growth and improve the yield of pakchoi.

The effects of exogenous melatonin on the growth, chlorophyll fluorescence parameters and related components of distribution of heat dissipation in tomato seedlings under Ca (NO3) 2 stress were studied in this experiment. The results showed that calcium nitrate stress inhibited the growth of tomato seedlings, reduced Y (II), Fv’/Fm’, qP and ETR, and produced photoinhibition on tomato seedlings. Spraying exogenous melatonin could increase the growth of tomato seedlings under calcium nitrate stress. Melatonin regulated qP and ETR under calcium nitrate stress, reduced the ratio of Y(NPQ), Y(NO), and increased the ratio of Y(II). Further analysis of NPQ and its three components, which including qE, qT and qI, showed that NPQ and its three components were significantly increased in the stress treatment group, while melatonin could inhibit the increase. Thus, it indicated that exogenous melatonin could effectively alleviate the growth of tomato seedlings under calcium nitrate stress, maintain the reasonable distribution of light energy, and protect the photosystem II from light damage caused by excess light energy.

A computational fluid dynamics (CFD) model for the closed plant factory has been developed in this study, the experimental validation of CFD model with the air velocity value was compared with the measured air temperature value. The results showed that the mean relative error of validation with the air velocity was 15%, and comparable with experimentally observed air temperature profile inside the plant factory with RMSE of 3% which shows the utility of CFD to study plant factory microclimatic parameters.

At present, the problem of antibiotic pollution in soil is becoming more and more serious, and antibiotics entering the soil can be absorbed by plants, causing normal physiological metabolism inhibition. In this experiment, the effects of tetracycline(TC) and oxytetracycline(OTC) on the growth of lettuce were studied. Matrix culture experiments were used to investigate the effects of different levels (0, 2, 10, 50, and 250 mg / kg) of TC and OTC on the growth of lettuce, chlorophyll fluorescence parameters, and antioxidant enzyme activities. The results showed that TC and OTC caused different degrees of inhibition on the growth of lettuce due to the different concentrations. Under antibiotic’s treatment, Fv / Fm, Fv ‘/ Fm’ and Y (II) of lettuce also showed a downward trend under tetracycline(TCs) treatment, however, the non-photochemical quenching (NPQ) of absorbed light energy showed an increasing trend. TCs also inhibited the antioxidant enzyme activity of lettuce, SOD activity was reduced by 3.27 (light concentration) and 52.68% (high concentration), and POD activity was decreased by 6.27 (light concentration) to 55.86% (high concentration) compared to control. The results showed that TCs could cause oxidative stress on plant growth, which should be concerned.

Mucilage cells were generally distributed in the vegetative organs of dicotyledons. We tried to analyse the relationship which was unknown between mucilage cells and the frost resistance by plant tissue staining technique, semi-lethal temperature and freezing injury index in Sedum aizoon L.The results showed that the number of mucilage cells was significantly larger than control group in the leaves and stems with experimental group. The semi-lethal temperatures were -3.34°C and

The effects of application of straw derived from cadmium (Cd) accumulator plants (Siegesbeckia orientalis, Conyza canadensis, Eclipta prostrata, and Solanum photeinocarpum) on growth and Cd accumulation of lettuce plants grown under Cd exposure were studied. Treatment with straw of the four Cd-accumulator species promoted growth, photosynthesis, and soluble protein contents and enhanced the activities of peroxidase in leaves of lettuce seedlings. The biomass of shoot of lettuce from high to low in turn is the treatment of C. canadensis straw > S. photeinocarpum straw > S. orientalis > E. prostrata > Control. The Cd content in edible parts (shoots) of the lettuce plants was significantly decreased in the presence of straw from the Cd-accumulator species, except the presence of the straw of E. prostrata. And, the greatest reduction in Cd content in shoots was 27.09% in the S. photeinocarpum straw treatment compared with that of the control. Therefore, application of straw of S. orientalis, C. canadensis, and S. photeinocarpum can promote the growth of lettuce seedlings, and decrease their Cd accumulation, when grown in Cd-contaminated soil, which is beneficial for production of lettuce safe for human consumption.

To test the feasibility of multi-rootstock grafting, bottle gourd and pumpkin were used as rootstocks in a comparative analysis of the effects of single, dual, and threefold rootstock grafting on the plant growth, fruit yield, and quality of watermelon. Results showed that different grafts have significant effects on the abovementioned properties. The appropriate dual/threefold rootstock grafting allowed for higher survival rates. The combined rootstock of bottle gourd and pumpkin can enhance the plant growth potential and lower the incidence of wilt. The single fruit weight of the grafted plants with a combined rootstock from bottle gourd and pumpkin was the median of the weights obtained with the pumpkin rootstock and the bottle gourd rootstock. The plot yield of grafted plants with a pumpkin rootstock was higher than that of the plants with a bottle gourd rootstock. The low soluble solids content of the fruit grafted with a pumpkin rootstock had relatively high acidity, which could be improved by adding bottle gourd to the rootstock. The vitamin C content of the grafted fruit from the combined bottle gourd and pumpkin rootstock was higher than that of plants grafted with either bottle gourd or pumpkin alone. The subsequent analysis showed that the combined rootstock of bottle gourd and pumpkin has significant or extremely significant interaction effects on the stem diameter, number of leaves, single fruit weight, plot yield, and fruit vitamin C content of the grafted watermelon plants, which probably led to the higher related index values of some of grafting combinations.

The difference of cold resistance between aboveground and underground parts was compared by measuring the growth and cold-resistance physiology of dormancy-released Sedum aizoon L. seedling with sprout at -5, 0 and 5 degrees Celsius respectively. The results showed that with the decreasing temperature, the plant height and root length all showed a downward trend, and the plant height decreased more than root length. The aboveground fresh weight showed an upward trend, while the underground fresh weight showed a downward first and then upward trend. The relative electrical conductivity (REC), tissue water content, total soluble sugar and free proline content all showed an upward trend, while malondialdehyde (MDA) content showed a downward trend in leaves. The content of soluble protein showed a downward first and then upward trend in leaves. The changing trend of roots was the same as leaves in REC, total soluble sugar and soluble protein content, but the REC of roots increased less than leaves. There was no significant change in tissue water content, free proline and MDA content in roots. At the same low temperature, roots were all higher than leaves in the content of total soluble sugar and soluble protein, while the tissue water content and MDA content were the contrary. In conclusion, the cold resistance of the underground part was stronger than aboveground part in Sedum aizoon L. seedling with sprout.

Excess nitrate stress has become a threat of environmental issues to crop cultivation in China. While measures of remediation and knowledge of the mechanisms underlying excess nitrate stress are limited. Previous studies reported that melatonin could improve the plant resistance to abiotic stress. Thus, we investigated the role of melatonin on the photosynthetic characteristic involved in nitrate assimilation under the excess nitrate stress in lettuce (Lactuca sativa ). Lettuce plants were subjected to moderate excess nitrate stress (160 mM NO3 −) with/without supply of 1.0 μM melatonin. Results showed that adding of melatonin decreased the nitrate content both in leaves and roots. Melatonin also dramatically increased the fresh and dry weights in lettuce seedlings. According to the chlorophyll fluorescence parameters, exogenous melatonin inhibited the reduction inPSII, Fv'/Fm', qP and rETR caused by excess nitrate stress, while reduced NPQ. In conclusion, exogenous melatonin could decrease the nitrate content in lettuce tissues and enhance the activity of PSII as well as the light energy conversion efficiency for carbon assimilation.

The plant growth, stem sap flow, Na(+) and Cl(-) content, and the expression of vacuolar Na(+)/H(+) antiporter gene (LeNHX1) in the leaves and roots of tomato under different NaCl stresses (0.5% and 1%) were studied to analyze the effect of arbuscular mycorrhizal fungi (AMF) on Na(+) and Cl(-) accumulation and ion exchange. The results showed that arbuscular mycorrhizal (AM) plant growth and stem sap flow increased and salt tolerance improved, whereas Na(+) and Cl(-) accumulated. Na(+) significantly decreased, and no significant decline was detected in Cl(-) content after AMF inoculation compared with the non-AM plants. The LeNHX1 gene expression was induced in the AM and non-AM plants by NaCl stress. However, AMF did not improve the LeNHX1 level, and low expression was observed in the AM tomato. Hence, the mechanism that reduced the Na(+) damage to tomato induced by AMF has little relation to LeNHX1, which can export Na(+) from the cytosol to the vacuole across the tonoplast.

Melon (Cucumis melo L.)—an important horticultural crop that is often cultivated in simply equipped solar greenhouses in northwestern regions of China—usually suffers under poor water management. Arbuscular mycorrhizal (AM) symbiosis can play a major role in enhancing drought tolerance. Plant growth, physiological, and photosynthetic responses of melon plants inoculated with three Glomus species under two water conditions were investigated. Results show that inoculation with Glomus improves the physiological and photosynthetic parameters of inoculated seedlings compared with non-AM seedlings. Regardless of water conditions, plant height, root length, biomass production, antioxidant enzyme activity, soluble sugar content, net photosynthetic rate, and photosynthetic water use efficiency were elevated in AM seedlings compared to non-AM seedlings. Each Glomus species manifests unique effects under the two watering conditions. We posit that AM symbiosis can protect melon plants against water deficiencies by improving their antioxidant activity, bi-directional transport of carbohydrates, and photosynthetic capacity. In addition, regardless of water conditions, the most efficient fungus for melon (Cucumis melo L.) was Glomus mosseae.

Salinity toxicity is a worldwide agricultural and eco-environmental problem. Many literatures show that arbuscular mycorrhizal fungi (AMF) can enhance salt tolerance of many plants and some physiological changes occurred in AM symbiosis under salt stress. However, the role of ROS-scavenging enzymes in AM tomato is still unknown in continuous salt stress. This study investigated the effect of Glomus mosseae on tomato growth, cell membrane osmosis and examined the antioxidants (superoxide-dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; peroxidase, POD) responses in roots of mycorrhizal tomato and control under different NaCl stress for 40 days in potted culture. NaCl solution (0, 0.5 and 1%) was added to organic soil in the irrigation water after 45 days inoculated by AMF (Glomus mosseae). (1) AMF inoculation improved tomato growth under salt or saltless condition and reduced cell membrane osmosis, MDA (malonaldehyde) content in salinity. So the salt tolerance of tomato was enhanced by AMF; (2) SOD, APX and POD activity in roots of AM symbiosis were significantly higher than corresponding non-AM plants in salinity or saltless condition. However, CAT activity was transiently induced by AMF and then suppressed to a level similar with non-AM seedlings; (3) higher salinity (1% level) and long stress time suppressed the effect of AMF on SOD, APX, POD and CAT activity; (4) this research suggested that the enhanced salt tolerance in AM symbiosis was mainly related with the elevated SOD, POD and APX activity by AMF which degraded more reactive oxygen species and so alleviated the cell membrane damages under salt stress. Whereas, the elevated SOD, POD and APX activity due to AMF depended on salinity environment.