Melatonin Alleviates Abscisic Acid Deficiency Inhibition on Photosynthesis and Antioxidant Systems in Rice under Salt Stress

Melatonin and abscisic acid,as major plant hormones,play important roles in the physiological and biochemical activities of crops,but the interaction between the two under salt stress is not yet clear.This study investigated the endogenous levels of melatonin and abscisic acid in rice by using exogenous melatonin,abscisic acid,and their synthetic inhibitors,and examined their interactions under salt stress.The research results indicate that melatonin and abscisic acid can improve rice salt tolerance.Melatonin alleviated the salt sensitivity caused by abscisic acid deficiency,increased antioxidant enzyme activity and antioxidant content in rice treated with abscisic acid synth-esis inhibitors,and reduced total reactive oxygen species content and thiobarbituric acid reactive substance accu-mulation.Melatonin also increased the activity of key photosynthetic enzymes and the content of photosynthetic pigments,maintaining the parameters of photosynthetic gas exchange and chlorophyllfluorescence.In summary,melatonin alleviated the effects of abscisic acid deficiency on photosynthesis and antioxidant systems in rice and improved salt tolerance.This study is beneficial for expanding the understanding of melatonin regulation of crop salt tolerance.

Three Salts of Labdanic Acids from Andrographis paniculata (Acanthaceae)

Three salts of labdanic acids, named as magnesium andrographate, disodium andrographate and dipotassium andrographate 19-O-beta -D-glucoside were isolated from the hydrophilic extract of Andrographis paniculata Nees. (Acanthaceae), together with guanosine, uridine, 6-epihardpagide, procumbide, violanthin and apigenin 7-O-beta -D-glucoside. Their structures were determined by spectroscopic analysis and chemical transformation.

Effect of bile salts and bile acids on human gastric mucosal epithelial cells

Objective：To explore the effect of bile salt and bile acid on cultured eternalized human gastric mucosa epithelium GES-1 cells. Methods：Cultured eternalized human gastric mucosa epithelium GES-1 cells were treated with media containing 6 different kinds of bile salts and 3 different kinds of bile acids and their mixture with different concentrations： GCDC（glycochenodeoxychoμte）, GDC （glycodeoxychoμte）, GC（glycochoμte）, TCDC（taurochenodeoxychoμte）, TDC（taurodeoxychoμte）, TC （taurochoμte）, LCA （lithocholicacid）, CA（cholic acid）, DCA（deoxycholic acid）（50 μ mol/L,250 μ mol/L,500 μ mol/L,1000 μ mol/L）, DY（mixture of bile salts） and DS（mixture of bile acids）（250 μ mol/L,500 μ mol/L,1000 μ mol/L,1500 μ mol/L, 2000 μ mol/L）, in comparison with the control group（in normal media without bile salts and bile acids）. Cell proliferation was assessed by MTT（3-[4,5-Dimethylthiaolyl]-2,5- diphenyl-tetrazolium bromide） assay for 72 hours with different concentrations and the apoptotic cells were assayed by flow cytometry （FCM） with Annex V-FITC conjugated with propidium iodide（PI） staining for 24 hours with different concentrations（1500,2000 μt mol/L）. Results：There was no significant difference in morphology and cell proliferation in GC group after 24-72 h. Low concentration（50 μ mol/L） of GCDC, GDC, TCDC, TDC and TC accelerated gastric epithelial cell growth in a dosage-time dependent manner. At middle concentration （250-500 μ mol/L）, it showed positive effect after 24-48 h, while negative effect after 72 h. At high concentration（1000 μ mol/L）, it accelerated gastric epithelial cell growth after 24h and show consistent inhibition even leading to necrosis after 48-72 h. LCA and CA showed a positive effect on the concentration of 50 μ mol/L after 24-72 h, while 250-1000 μ mol/L showed a trend towards apoptosis after 24-72 h. At 50-500 μmol/L, DCA showed proliferation after 24 h and apoptosis after 48-72 h, but showed necrosis after 24-72 h at 1000 μmol/L. DY and DS could facilitate normal gastric mucosa epithelial cell growth at low concentration （250-500 μ mol/L）, however at 1000-2000 μ mol/L the trend shifted from apoptosis to necrosis. FCM with Annexin-V conjugated with PI staining revealed that GCDC, GDC, GC, TCDC, TDC, TC, LCA, CA, DCA, DY and DS induced apoptosis of human gastric mucosal epithelial cells. They were all significantly higher than that of the control（P 〈 0.05）, but there was no significant difference in GC group （P 〉 0.05）. The bile salts induced apoptosis in a time-dose-dependent manner. Conclusion：Our results suggested that bile acid and bile salt is the trigger of injury in human gastric mucosal epithelial cells.

Microwave-assisted base-free synthesis of trans-cinnamic acids using hypervalent iodonium salts

A fast and convenient base-free Heck reaction of acrylic acid with hypervalent iodonium salts was achieved under microwave irradiation in water, providing a simple method for the synthesis of trans-cinnanfic acids in good yields in short time.

HYDROXYLATION OF BENZENE BY HETEROPOLY ACIDS(SALTS)CONTAINING VANADIUM

Direct hydroxylation of benzene catalyzed by vanadium-con- taining heteropoly compounds with Keggin or Dawson structure has been investigated.The effects of several factors upon the hydroxylation reaction have also been examined.It is indicated that the highest yield of phenol reached 76%(based on H_2O_(?))with 99.4～100% selectivity.

Analysis of Organic Acids Accumulated in Kochia Scoparia Shoots and Roots by Reverse-phase High Performance Liquid Chromatography Under Salt and Alkali Stress

Several organic acids accumulated in Kochia Scoparia shoots and roots were studied by means of reverse-phase high performance liquid chromatography with a C18 column. Five types of binary organic acids were separated. The organic acid concentrations were determined in K. Scoparia seedlings stressed by saline （NaCI） and alkaline （NaHCO3） at the same Na^＋ concentration. Concentrations of organic acids are stimulated by alkaline because the cells will adjust their pH values through the accumulation of organic acids, when the environment is basic. The concentrations of oxalic acid and succinic acid are higher than those of other organic acids, including tartaric acid and malic acid, and the concentration of citric acid is the lowest. The concentrations of the organic acids in the roots are higher than those in the shoots under salt（NaCI） stress, but the results are opposite while the roots are under alkali （ NaHCO3 ） stress. This indicates that there are different adaptive strategies for K. Scopar/a seedlings in organic acid metabolism under salt and alkali stress.

Increasing Fatty Acids in Rice Root Improves Silence of Rice Seedling to Salt Stress

Salt stress is one of the major abiotic stresses around the world, and salt salinity is one of the major constrains affecting rice production (Tu et al, 2014;Reddy et al, 2017). According to the statistics, more than one billion hectares of the land in the major continents are affected by salinity (Fageria et al, 2012;Zhou et al, 2018). Rice is a salt sensitive crop, considered more sensitive to salt stress during early stage (Hasanuzzaman et al, 2009). Understanding the method to improve plant salt tolerance is a potential way to enhance agriculture productivity in the future (Jing and Zhang, 2017). Polyunsaturated fatty acid (PUFA) on plasma membrane plays important roles in salt tolerance through enhancing the activity of Na^+/H^+ transporters (López-Pérez et al, 2009).

Influence of Neutral Salts and pH on Exchangeable Acidity of Red Soil and Latosol Colloids

In the present work, the exchangeable acidity of a red soilcolloid and a latosol colloid at different pH during reacting withfour neutral salts was measured. The results show that theexchangeable acidity increased with increasing amounts of the neutralsalts added, and the relation between them was almost linear. Whenthe amount of the neutral salt added was lower than a certain value,the slop of the line was high, and the slop turned low when theamount exceeded that value, so there was a turning point in eachline. The addition amounts of the neutral salts for the turningpoints were affected by the cation species of the neutral salts, butpH had less effect on them. After the turning points occurred, theexchangeable acidity of the red soil colloid still graduallyincreased with the addition amounts of the neutral salts, but that ofthe latosol colloid did not increase any more.

Viscometric Studies of Some Amino Acids/Peptides in Aqueous K2SO4/KNO3 Solutions at Different Temperatures (298.15 - 323.15 K)

Viscosities of L-leucine/L-glutamine/L-alanine/glycylglycine + 0.512 mol·kg-1 aqueous K2SO4/0.512mol·kg-1 aqueous KNO3 solutions have been measured as a function of molal concentration of amino acids/peptides at different temperatures (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. Using the viscosity values of the studied systems the viscosity B-coefficients and activation parameters: , , and have been computed. The B-coefficient is a quantity of active solvodynamic measurements of solvated ion and also is overseen through magnitude and form properties of solute, and the basic effects made by means of the solute-solvent functioning. The experimental and computed parameters have been discussed in terms of ion-ion, hydrophilicion and hydrophobicion interactions operative in the systems.

Preparation of iminodiacetic acid salts from iminodiacetonitrile with additives assisted in subcritical water

Here, the employment of subcritical water as an environmentally benign media has shown a certain potential for the hydrolysis ofiminodiaeetonitrile （IDAN）. Additives （such as NH3.H2O, （NH4）2CO3, K2CO3） were selected to investigate the reactivity ofiminodiacetonitrile in the solutions of these species in the subcritical region for the possibility of preparing iminodiacetic acid （IDA） salts. A series of reactions were performed in a high temperature and pressure batch reactor with temperature ranging from 200 to 260 ℃, time ranging from 4 to 10 min, pressure ranging from 5 to 25 MPa and varying concentration of additives to consider the influence of these parameters on the yield of IDA salts. Reactivity of IDAN was not illustrated with the conversion but with respect to the yield of resultant IDA salts. The results demonstrate that hydrolysis reactivity of IDAN under the examined conditions has shown a remarkable sensitivity to the pH of the system at initial point of the reaction stage, and temperature effect is also obvious. Based on the results, possible reaction pathway and mechanism were proposed.

Novel Perchlorate and Sulphate Salts of 2-Aminonicotinic Acid:Synthesis,Characterization,Thermal Studies and Hirshfeld Surface Analysis

Since 2-aminonicotinic acid is a zwitterionic molecule,the salt or co-crystal strategy was used for the precipitation under identical conditions and obtained two novel salts： salt 1 with 2：1：2 stoichiometry of 2-aminonicotinic acid：perchloric acid：H2O and salt 2 with 2：1：3 stoichiometry of 2-aminonicotinic acid：sulfuric acid：H2O. Their crystal structures were characterized by single-crystal X-ray diffraction,differential scanning calorimetry（DSC） and thermogravimetric analyses（TGA）. The structure determination shows that two salts are both primarily stabilized by the strong N–H…O hydrogen bonding interaction between 2-aminonicotinic acid and its corresponding acids. Constituents of the salt-crystalline phase were also investigated in terms of Hirshfeld surfaces. In the crystal lattice,a three-dimensional hydrogen-bonded network is observed,including the formation of a two-dimensional molecular scaffolding motif. Hirshfeld surfaces and fingerprint plots of two salts show that the structures are stabilized by H…H,O–H…O and C–O…π intermolecular interactions.

Effects of salt and rice flour concentration on microbial diversity and the quality of sour meat,a Chinese traditional meat

This study investigated the effects of salt(3%and 6%,m/m)and rice flour(10%and 20%,m/m)addition in sour meat,a traditional Chinese fermented meat.It was found that salt has greater effect than rice flour addition in spontaneous fermentation.Low-salt groups had lower pH and higher titratable total acid.In the low-salt groups,the dominant genera were Lactobacillus and Lactococcus,whereas Staphylococcus,Weissella,and Tetragenococcus were dominant in the high-salt groups.Higher total free amino acids and essential amino acids,organic acids,hexanoic acid ethyl ester and octanoic acid ethyl ester were found in the low-salt groups.The RDA analysis revealed that Lactococcus was closely related to product quality,with the S3F10(3%salt and 10%rice f lour)group outperforming the others in the sensory evaluation.Therefore,3%salt and 10%rice flour were considered more appropriate for the production of healthy and tasty fermented sour meats.

Photodynamic Therapy of Cancer Cells with Methanesulfonate Salts of 5-Aminolevulinic Acid and Its Derivatives

A series of 5-aminolevulinic acid and its alkylester methanesulfonates was exploited to photodynamic therapy（PDT） of human lymphocytic cells, U-937 in vitro. The PDT efficiency is influenced by the concentration and incubation time. Generally, for ALA and its alkylester methanesulfonates, the cell survival rate decreases and the accumulation ability of PplX increases with the concentration and incubation time. We found that the longer carbon chain methanesulfonates（C5-S, C6-S, C8-S） exhibit better PDT effect than ALA methanesulfonate. This possibly provides a promising route to the clinical application ofPplX-mediated PDT to cancer cell.

STUDIES ON ISOMERIZATION OF δ－NITRILES TO PYRIDONES CATALYZED BY INORGANIC ACID SALTS

Butanons, 2-pentanone,2-hexanone and cyclohexanone were cyanoethylated,using KOH/HOCH2CH2OCH2 as a catalyst,giving yields of more than 30%.There inorganic acid salts,NaHSO4,KHSO4 and KH2PO4,were employed for the first time to catalyze the isomerization of δ-keto nitriles obtained above to correspounding pyrklones.The three catalysts were found to bave significantly high activities and their activities have close relation to their physical properties,especially are in direct proportion to their acidities.

Feeding Calcium Salts of Linseed Oil on Productive Performance and Milk Fatty Acid Profile in Grazing Dairy Cows

The objective of this study was to determine the effect of supplying calcium salts of linseed oil (Ca-FA) rich in omega-3 (α-linolenic acid) on the production and chemical composition of milk and its nutraceutical value in dairy cows in early lactation. The trial lasted 12 weeks (2 weeks for adaptation to lipids and 10 weeks of data collection). A total of 36 Holstein dairy cows with 58.0 ± 17.0 days in milk (DIM), 594.1 ± 92.4 kg BW, 2.6 ± 1.5 parity and 38.9 ± 9.3 kg milk day-1 were used in a randomized complete block design. The treatments were: 1) Omega-3 (O3): 5.2 kg DM day-1 of concentrate including 0.7 kg DM of Ca-FA + 13.5 kg DM day-1 of partial mixed ration (PMR) + 12 kg DM day-1 of alfalfa pasture (Medicago sativa) and 2) Control (C): diet similar to O3 but lipid supplementation was replaced by cracked corn grain so that the diets were isoenergetic. No treatment effect was detected (P > 0.05) for any milk production and composition variables, except for urea in milk that was slightly higher in O3 (P = 0.02). The treatment × week interaction was significant (P < 0.05) for fat yield and content, with differences (P < 0.01) only in the 3rd week of the data collection period in favor of group C (1.39 vs. 1.13 kg·day-1 and 3.86% vs. 3.23% for fat yield and content, respectively). Total DMI and PMR were similar (P > 0.05) between treatments. Concentrate intake was higher (P < 0.01) in C compared with O3. Pasture DMI tended (P = 0.06) to be greater for cows that received the O3 treatment compared with C. Total metabolizable energy (ME) intake was similar (P = 0.44) between treatments. No treatment effect was detected (P > 0.05) in rumen environment parameters. Supplementation with Ca-FA reduced (P < 0.05) the hypercholesterolemic fraction of milk (C12:0, C14:0 and C16:0, -13.6%, -7.4% and -9.0%, respectively). The concentration of α-linolenic acid (C18:3n-3) increased (108%, P < 0.01) in O3 group compared with group C. The absence of negative effects of lipids on the fat content of milk and ruminal fermentation suggests that protection by saponification was effective. The supplementation with Ca-FA (0.85 kg·day-1) improved the healthy value of the milk.

Pentacoordinated Spirophosphoranes from Amino Acid Sodium Salts

The reactions of 2-chloro-1,3,2-dioxaphospholane with various sodium salts of amino acids to afford the pentacoordinated spirophosphoranes containing amino acid were studied by NMR spectra techniques. The results showed that natural alpha-amino acids had greater ability than beta-amino acids to form the pentacoordinated species, which is important in the biosynthesis and prebiotic synthesis of of oligopeptides and proteins.

Effects of Salt Stress on Fatty Acid Composition of Thylakoid Membrane of Two Rice Cultivars Differing in Salt Tolerance

[Objective] The aim of the study is to understand the changes of fatty acid composition of rice thylakoid membrane under salt stress.[Method] Under salt stress of different concentrations of NaCl,rice seedlings of Pokkali and Peta with six leaves and one central leaf were used as experimental materials to extract the fatty acid from their thylakoid membranes,and gas chromatograph(1890)was used to analyze fatty acid composition.[Result] Fatty acid component 14∶0,18∶0,16∶1(3t),18∶1 in both the two experimental materials showed little variations in the first four days of salt stress,whereafter they increased slightly;while the fatty acid component 16∶0 and level of saturation of fatty acid(LSFA)showed the similar variation trend in the first four days of treatment compared to those of the fatty acid components mentioned above,whereafter they rose in Pokkali and presented an opposite variation trend in Peta;fatty acid component 18∶3 and level of unsaturation of fatty acid(LUFA)reduced all the time under stress condition,and the reducing amplitude in 100 mmol/L NaCl treatment group was smaller than that of 100 mmol/L NaCl treatment group,and in Pokkali was smaller than that in Peta under specific conditions.Meanwhile,level of saturation of fatty acid in both experimental materials increased,and the rising amplitude in Peta was smaller than that of Pokkali.[Conclusion] With regard to LUFA,Pokkali is endowed with more salt tolerance than Peta.

Physiological Mechanism of Salicylic Acid for Alleviation of Salt Stress in Rice

Soil salinity is one of the most important problems of crop production in estuarine and coastal zones. Improvement in salt tolerance of major food crops is an important way for the economic utilization of coastal zones. This study proved that the application of salicylic acid(SA) improved the growth and yield under salt stress conditions and investigated its physiological mechanisms for salt tolerance. The investigation on the effect of SA for salt tolerance during germination showed that the decreased rates of germination and growth(in terms of shoot and root lengths) by the salt stress were significantly increased by the SA application(SA + NaCl). The treatment of SA to the high and low saline soils enhanced the growth, yield and nutrient values of rice. The effects of SA on Na^+, K^+ and Cl~– ionic accumulation were traced under salt stress condition by inductively coupled plasma optical emission spectrometry and ion chromatography. It was revealed that the increased accumulation of Na^+ and Clˉ ions by the salt stress were reduced by SA application. An increased concentration of endogenous SA level was detected from the SA-treated rice varieties(ASD16 and BR26) by liquid chromatography electrospray Ionization-tandem mass spectrometry. The activities of antioxidant enzymes such as superoxide dismutase, catalase and peroxidase were increased by salt stress whereas decreased by the SA application. The study proved that the application of SA could alleviate the adverse effects of salt stress by the regulation of physiological mechanism in rice plants. In spite of salt stress, it can be applied to the coastal and estuarine regions to increase the rice production.

Effect of Ascorbic Acid and Silicium on Photosynthesis, Antioxidant Enzyme Activity, and Fatty Acid Contents in Canola Exposure to Salt Stress

The effects of exogenous ascorbic acid and silicium on leaf fresh weigh, seed yield, photosynthesis, changes of the activities of major antioxidant enzymes, nitrate reductase activity, proline accumulation, chlorophyll content, and fatty acid composition were investigated in salt-stressed canola. A hydroponic pot experiment was conducted based on randomized complete block design, factorial arrangement was used with 16 combinations of salinity stress （0, 100, 200, and 300 mmol L-1 NaC1）, ascorbic acid （0 and 30 mmol L-1）, and silicium （2 and 4 mmol L-1 from potassium silicate） with three replicates. The results showed that salinity significantly decreased leaf area and leaf fresh weight, seed yield, photosynthesis, nitrate reductase activity, chlorophyll content, and seed protein percentage. Conversely, respiration, antioxidant enzymes activity, proline accumulation, and linolenic acid percentage increased due to salt stress. Ascorbic acid application improved photosynthesis and seed yield and mitigated antioxidant enzyme activity. In addition, nitrate reductase activity and chlorophyll a and b were positively affected by ascorbic acid. Regarding silicium application, that was found that leaf area, leaf fresh weight, seed yield and photosynthesis, ascorbate peroxidase activity, nitrate reductase activity, and chlorophyll content increased, while respiration decreased. Furthermore, silicium had not significant effect on antioxidant enzyme activity. In general, ascorbic acid and silicium were involved in the defensive mechanisms against salinity stress and it can be suggested that, ascorbic acid and silicium application had positive effect on canola growth under conditions of salt stress.

Effects of Cinnamic Acid on Bacterial Community Diversity in Rhizosphere Soil of Cucumber Seedlings Under Salt Stress

To investigate the effects of a plant autotoxin, cinnamic acid, on bacterial communities in the rhizosphere soil of cucumber seedlings under salt stress, we used cucumber as the experimental material, cinnamic acid as the autotoxin, and NaCl to apply salt stress. Bacterial communities in the rhizosphere soil were analyzed using polymerase chain reaction （PCR）, denaturing gradient gel electrophoresis （DGGE）, and clone sequencing. Salt stress decreased the diversity of bacterial species in rhizosphere soil of cucumber seedlings at several growth stages. Cinnamic acid exacerbated the effects of salt stress at high concentrations, but alleviated its effects at low concentrations. Cloning and sequencing results indicated that DGGE bands amplified from soil samples showed high homology to uncultured bacterial species. Cinnamic acid at 50 mg kg^-1 soil improved cucumber growth and was the most effective treatment to alleviate the effects of salt stress on bacterial communities.