Effects of salicylic acid on growth, biochemical constituents in pepper (Capsicum annuum L.) seedlings

In the present study, the effect of different concentrations of salicylic acid which is an endogenous organic acid in plants and which is commonly cited as a hormone, on the growth and some other parameters of pepper (Capsicum annuum L. cv.) seedlings was investigated. The solutions were applied to the roots of seedlings using hydroponic method. In general, 1.5 mM concentration of salicylic acid had a stimulating effect while 5 and 10 mM concentrations had varying degrees of inhibitive effects on the seedlings. Although 0.3 mM SA application produced prominent results in the case of all parameters, the difference was not found statistically significant. The inhibitive effect produced by high SA was found much more dominant than the stimulating effect of low SA concentrations. Thus, it was established that SA had a bidirectional physiological effect on the seedlings in a concentration-dependent manner.     

Characterization of pre-gelatinized maize starch-zein blend films produced at alkaline pH

Biodegradable materials are considered as alternative to synthetic materials to alleviate the environmental burdens caused by petroleum based synthetic materials. Biopolymer blends have been extensively researched to improve the material properties of biopolymer-based materials for potential replacement of non-biodegradable materials. Compatible blends of pre-gelatinized maize starch (uncomplexed or complexed with stearic acid) and commercial zein in 0.1 M NaOH were used to produce the films. The effect of the ratio of uncomplexed starch, zein and starch complexed with stearic acid on the tensile, water vapour and oxygen barrier and thermal properties of the composite films were investigated. Blending zein with starch increased the tensile strength and reduced the tensile strain compared to starch films. Addition of starch complexed with stearic acid to the blend further increased the tensile strength and decreased the elongation at break. Both blending zein with starch and addition of starch complexed with stearic acid to the blend decreased the water vapour permeability, however, the oxygen permeability was increased compared to starch films. The starch-zein blend films had an endothermic temperature and thermal transition in between the uncomplexed maize starch and zein films suggesting possible compatibility at molecular level. The microstructure of the blend films also showed good miscibility of pre-gelatinized starch and commercial zein. In conclusion alkaline solvent (0.1 M NaOH) could produce compatible starch-zein blends that can produce films with improved tensile strength and water vapour permeability compared to starch films.     

Thermal and mechanical properties of environment-friendly ‘green’ plastics from stearic acid modified-soy protein isolate

Most plastics, at present, are petroleum-based and do not degrade over many decades under normal environmental conditions. As a result, efforts towards developing environment-friendly and biodegradable ‘green’ plastics for various commercial applications have gained significant momentum in recent years. Soy protein isolate (SPI)-based ‘green’ plastics have been shown to suffer from high moisture sensitivity and low strength. These properties have limited their use in most commercial applications. They are also difficult to process into sheets without any plasticizer. The commonly used plasticizer, glycerol, tends to leach out over time producing time-dependent properties, which is highly undesirable for commercial applications. The objectives of the current research are to reduce the moisture sensitivity and simultaneously improve the tensile properties of SPI by incorporation of stearic acid without affecting its biodegradability. The effect of stearic acid and glycerol on the tensile and thermal properties of SPI has been characterized using various techniques to determine the interaction mechanisms between stearic acid and soy protein. Mechanical properties were characterized using Instron tensile tester. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD) techniques have been used to determine the effects of stearic acid and glycerol on the surface chemistry, thermal transitions and thermal degradation of the stearic acid modified SPI plastic (resin). The tensile test results show that Young’s modulus increased on increasing the stearic acid content, reaching the maximum value at about 25% (by weight of SPI powder) stearic acid. Further increase in stearic acid content from 25 to 30% led to a reduction in Young’s modulus. The moisture content, fracture stress, strain, and energy at break decreased steadily on increasing the stearic acid from 0 to 30% for SPI containing 30% glycerol. At 25% stearic acid content, the modulus and the fracture stress increased significantly, whereas the fracture strain, energy at break and the moisture content decreased on reducing glycerol content. Scanning electron microscopy photomicrographs of fractured surfaces showed a layered structure for stearic acid modified-SPI resin. TGA measurements showed that the thermal degradation of stearic acid modified-SPI resin initiated at higher temperature than the SPI resin. DSC scans indicated that stearic acid modified-SPI resin had a small degree of crystallinity, which was confirmed by X-ray diffraction patterns. Modifying SPI resin with stearic acid has been successful in obtaining better tensile and thermal properties as well as reduced moisture sensitivity without any processing problems.     

Physiological response of henna (Lawsonia inermise L.) to salicylic acid and salinity

Henna (Lawsonia inermis L.) is naturally cultivated from north-east Africa to India as a medicinal-industrial plant. The objective of this study was to evaluate the possible role of salicylic acid (SA) for mitigating the salinity stress. For this purpose, we evaluated the effect of three concentrations of SA (0, 40 and 80 μM) and salinity (0, ?3 and ?6 bar) on photosynthetic pigments, protein content, catalase (CAT, EC 1.11.1.6) activity, electrolyte leakage and leaf relative water content (RWC). The experiment was carried out with a factorial arrangement based on complete randomized design in triplicates at University of Kerman, Iran. The results revealed that salinity caused a significant decrease in photosynthetic pigments, protein content, RWC and quantum yield of henna. By increase in salinity levels from 0 to ?6 bar, the mean values of mentioned traits were reduced. CAT activity, electrolyte leakage, F₀ and F_m were elevated significantly with increasing the salinity concentration. Application of SA under salinity stress increased the photosynthetic pigments, protein content, CAT activity, leaf RWCs and quantum yield, while it decreased electrolyte leakage, F₀ and F_m. It can be concluded that SA alleviated the stress generated by NaCl possibly through the ameliorated antioxidant defense system.     

甘蓝型油菜MYB28转录因子对根肿菌和水杨酸的响应特征

MYB转录因子参与植物的生长发育和逆境胁迫过程，在植物防御相关信号反应中起着重要的调控作用。 为了明确MYB28在油菜与根肿菌互作中的作用，对感病甘蓝型油菜中双11中MYB28家族基因在根肿菌接种以及 水杨酸处理后的表达模式进行了分析。不同组织表达模式分析显示，相比于根和叶，BnaMYB28 在茎和种子中的表 达水平更高；BnaMYB28 基因在根肿菌和外源水杨酸处理下均有不同程度的表达响应，外源水杨酸处理下Bna⁃ MYB28-1 和BnaMYB28-3 上调表达，BnaMYB28-2 表达则受抑制。根肿菌侵染后，BnaMYB28-1 在整个侵染期表达 量均显著上调，但在加入水杨酸后表达被显著抑制；BnaMYB28-3 表达量在接菌后7 d和28 d显著上调，在关键皮层 侵染期（接菌后14 d）表达量与对照组相比没有变化，但在施加水杨酸处理后表达量显著上调。综上，外源水杨酸能 正向调控BnaMYB28-1 和BnaMYB28-3 表达，BnaMYB28-3 可能通过水杨酸信号路径参与油菜与根肿菌的互作。     

Oxidation of commercial (α-type) zein with hydrogen peroxide improves its hydration and dramatically increases dough extensibility even below its glass transition temperature

To improve the rheological properties of zein doughs, α-type zein and zein-starch doughs were prepared with the oxidising agents, hydrogen peroxide and peroxidase, which strengthen gluten-based doughs by cross-linking. Hydrogen peroxide and peroxidase increased zein dough extensibility compared to preparation with water. Hydrogen peroxide prepared zein doughs were extensible and cohesive below zein’s glass transition temperature. The doughs did not exude water and maintained flexibility when stored. Confocal laser scanning microscopy revealed that in zein-starch doughs prepared with hydrogen peroxide a thin continuous zein matrix was formed around the starch granules, whereas doughs prepared with water exhibited clumps of granules. SDS-PAGE of zein doughs and films treated with the oxidising agents showed no evidence of zein polymerisation, nor did Fourier transform infrared spectrometry reveal any significant changes in secondary structure. Further, hydrogen peroxide treatment did not increase zein film glass transition temperature, but it did increase transition enthalpy, and film water uptake increased with hydrogen peroxide concentration. The greatly increased extensibility of hydrogen peroxide prepared zein doughs and their improved water-holding are not due to oxidative cross-linking. It is proposed that the effects are primarily due to hydroxylation of amino acid aliphatic side chains, improving hydration through hydrogen bonding.     

Effect of different fractions of zein on the mechanical and phase properties of zein films at nano-scale

The phase behavior of zein films has been investigated at nano-scale using atomic force microscopy (AFM) and compared to the phase behavior of the bulk using a thermal characterization technique. The local surface properties of the films were evaluated as a function of water activity using AFM. The glass transition temperature (T_g) of zein films decreased with increasing water activity. Adhesion forces measured by the AFM force curves increased with increasing water activity. Topography of zein and zein fractions were evaluated both qualitatively and quantitatively by the use of AFM and dedicated software to calculate the surface roughness. It has been found that processing technologies (solvent casting, drop deposition and spin casting) has influence on the surface structures of films. The films which were formed by the alpha zein rich fraction were found to have highest roughness values. Sectional surface profiles revealed that α-zein films have mean roughness (R_a) of 1.808 nm and root mean square roughness (RMS) of 2.239 nm while β-zein films have mean roughness (R_a) of 1.745 nm and root mean square roughness (RMS) of 3.623 nm. The discussions conducted on the differences/similarities in the observations were based on the hydrophobic/hydrophilic properties and interactions of these zein fractions.     

水杨酸(SA)诱导植物对病虫害产生抗性及作用机制研究

水杨酸(SA)作为一种新型的抗病性诱导剂,其对植物病虫害的抗性诱导作用已成为研究的热点。本研究从水杨酸的基本性质及其在植物病虫害中的诱导抗性特点、水杨酸与水杨酸结合蛋白的相互作用、水杨酸介导的信号传导途径等方面初步探讨水杨酸诱导植物抗病性和抗虫性的作用机制及应用前景。     

Slow digestion property of microencapsulated normal corn starch

Starch is the main glycemic dietary carbohydrate, and its nutritional quality is associated with the amount of slowly digestible starch (SDS) that is beneficial to glycemic control. In the current study, a microencapsulation of normal corn starch by zein protein and its slow digestion property were investigated. A significant increase of SDS and RS was shown for starch capsules (weight ratio of zein to starch: 1:6) containing plasticizers of glycerol and oleic acid after high temperature (≥70 °C) treatment. Further studies showed a substantially decreased viscosity and the formation of an amylose–lipid complex after starch gelatinization. Thus, the hydrophobic physical barrier of the zein matrix and the amylose–lipid complex might together limit the water accessibility and starch swelling leading to a dense packing of starch materials with a high amount of SDS. The acceptable sensory property makes it an ideal ingredient for specialty food preparation and glycemic control.     

Effect of residual distillation water of 15 plants and three plant hormones on Scotch spearmint (Mentha × gracilis Sole)

Distillation waste water is a byproduct from steam distillation of aromatic crops, and is currently discharged into streams and rivers. We evaluated distillation waste water (extract) from 15 essential oil crops plus three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) as foliar spray for Scotch spearmint (Mentha × gracilis Sole). GA3 and Achillea millefolium extract decreased essential oil content. Hypericum perforatum extract increased α-pinene, whereas SA decreased it. H. perforatum extract increased β-pinene and sabinene concentrations relative to hormones but was not different from the control. H. perforatum also increased l-limonene, while SA and GA3 decreased myrcene and MJ and SA decreased l-limonene. Application of MJ and SA increased l-carvone concentration relative to the control and most other treatments. The sulfur concentration in plant extracts was positively correlated to β-caryophyllene. None of the residual distillation waters showed significant antimicrobial or antimalarial activity. The distillation waste water from essential oil crops may serve as a modifier for Scotch spearmint essential oil.     

Characterization of zein modified with a mild cross-linking agent

Zein, a predominant corn protein, is an alcohol-soluble protein extracted from corn and is an excellent film former. The characteristic brittleness of zein diminishes its usefulness as a film. It is well known that zein has a propensity for forming aggregates in solution. When zein molecules were cross-linked with 1-[3-dimethylaminopropyl]-3-ethyl-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), it was found that the film-forming property was improved and the aggregation phenomenon in solution was suppressed. At the air/water interface, native zein forms brittle film with rough surface, whereas cross-linked zein forms rigid film with very smooth and even surface. Tensile strengths of the films were shown to be greatly increased by cross-linking. Objectives of this study are to determine the cross-linking mechanism of zein, the optimum reaction conditions, characteristics of the reaction product, and mechanical properties of cross-linked zein film. Through viscosity and dynamic light scattering, the cross-linking reaction was monitored. Optimum amount of EDC and NHS was determined to be 30 mg each per gram of zein. The cross-linking of zein with EDC and NHS seemed to be self-terminating because the cross-linking reaction did not proceed to precipitation.     

外源水杨酸对盐胁迫下巴西蕉生理的影响

香蕉是世界进出口贸易中具有重要经济价值的水果,也是非洲国家的粮食作物。盐害是影响香蕉产量和品质的重要因子之一。巴西蕉是我国华南地区的主栽品种。水杨酸在植物生理和代谢中扮演重要角色。盐胁迫下,外源水杨酸处理巴西蕉（Musa AAA Cavendish var. Brazil）幼苗的生理指标的变化未见报道。本研究通过叶面喷施0、0.5、1.0、2.0 mmol/L外源水杨酸,测定70 mmol/L NaCl胁迫下的巴西蕉幼苗叶片相对含水量、叶绿素含量、脯氨酸含量等生理指标的变化。结果表明,盐胁迫下巴西蕉幼苗的叶片相对含水量和叶绿素含量与对照相比显著下降,而脯氨酸含量、可溶性糖含量、可溶性蛋白含量以及丙二醛含量与对照相比均显著上升。施加0.5、1.0 mmol/L水杨酸处理与盐胁迫相比提高叶片相对含水量和叶绿素含量,提高叶片脯氨酸、可溶性糖和可溶性蛋白的含量,并且降低叶片丙二醛含量,而2.0 mmol/L 水杨酸处理的叶片相对含水量、脯氨酸含量、可溶性糖和可溶性蛋白含量与盐胁迫处理的差异不显著。因此,施加较低浓度的水杨酸（0.5、1.0 mmol/L）可在一定程度上缓解盐胁迫现象,但是高浓度水杨酸（2.0 mmol/L）缓解效果不明显,其中以1.0 mmol/L水杨酸处理效果最好。     

Preparation and characterization of gluten-free sheeted doughs and noodles with zein and rice flour containing different amylose contents

This study aimed to explore the feasibility of zein as a gluten alternative in preparing sheeted doughs with rice flours containing different amylose contents (12, 19, and 26%) that were successfully slit into noodle strands. Rice-zein mixtures with lower amylose contents exhibited lower pasting parameters and the high amylose paste samples possessed more elastic properties. Higher water absorption was observed in the low amylose rice-zein mixture whereas the use of zein were effective in increasing the stability of rice dough regardless of amylose content. In case of thermal conductivity, the noodle doughs prepared with high amylose rice-zein mixture had low thermal conductivity, probably implying a long cooking time. The structure of the rice-zein noodles had a tendency to become firmer with increasing levels of amylose by showing greater breaking stress and resistance to extension that could be correlated to reduced cooking loss.     

Improvement of zein dough characteristics using dilute organic acids

The replacement of gluten in dough products poses a major challenge. Preparing zein doughs in dilute acetic acid and lactic acid, such as produced during sourdough fermentation, was investigated. Increasing acid concentrations (0.7, 1.3 and 5.4% [v/v]) increased zein extensibility and reduced the stress and related parameters. Preparation of zein-maize starch/-rice doughs in dilute organic acids improved dough properties to the extent that the doughs could hold air and be inflated into a bubble by Alveography. Further, they exhibited similar Stability (P), Distensibility and deformation energy (W) to wheat flour dough. Confocal laser scanning microscopy revealed an ordered linear fibril network in zein and zein-rice flour doughs prepared in the dilute acids, which became uniform with increasing acid concentration. SDS-PAGE showed that the acids did not hydrolyse or polymerise the zein. FTIR indicated that the acidic conditions slightly increased the proportion of α-helical conformation in the zein doughs, possibly as a result of deamination. This conformational change may be responsible for the considerably improved zein dough properties. Zein doughs prepared in dilute organic acids show potential as a gluten replacement in gluten-free formulations.     

Study of the physical properties of kafirin during the fabrication of tablets for pharmaceutical applications

Kafirin and protein bodies were extracted from a condensed tannin-free white Sudanese cultivar of sorghum (Dabar). The extracted materials were characterized by SDS-PAGE. The potential of kafirin as a tablet matrix for pharmaceutical applications was studied. Tablets composed of kafirin, calcium hydrogen orthophosphate, caffeine and magnesium stearate were prepared by direct compression. The tablets showed appropriate levels of hardness and friability. Drug release studies showed that caffeine dissolution was greater in 0.1 M HCl than in either phosphate buffer (pH = 6.8) or distilled water. Deamidation of the protein in acid conditions might explain this observation.FTIR analysis showed that the secondary structure of kafirin was found to be mainly governed by α helices with some β sheets. Upon tabletting, there was a change in protein conformation, which was recovered upon dissolution irrespective of the dissolution media. This might be explained by the loss of protein coil to coil interaction during tabletting (possibly due to the diluting effect of calcium hydrogen orthophosphate). This was later recovered when tablets were dissolved due to the hydrophobic interactions between the kafirin proteins.In summary, this work has shown that kafirin has a potential for use as a tablet for drug delivery.     

Oleoresin yield of Pinus elliottii in a subtropical climate: Seasonal variation and effect of auxin and salicylic acid-based stimulant paste

The extraction of induced oleoresin from Pinus elliottii through bark streaking supplies products to the food, pharmaceutical and chemical industries. Resin flow is a typical defense response in conifers and is controled by various environmental factors. Although many studies have focused on oleoresin production in temperate forests, particularly in response to bark beetle attacks, relatively little is known about the physiological regulation of sustainable resin exudation in subtropical planted forests, in which commercial exploitation of this product is favored by the absence of significant pest insect populations. Therefore, the annual oleoresin yield of approximately 2660, 28-year-old trees from different sites was monitored for two consecutive years in southern Brazil. Plain wounding and wounding followed by application of a commercial resin stimulant paste containing the ethylene precursor 2-chloroethylphosphonic acid (CEPA) were used as reference treatments. Different concentrations of auxin, paraquat, yeast extract, and salicylic acid (isolated or in combination with CEPA) were also tested. Higher resin yields were associated with spring and summer, whereas winter had lower but significant yields. Auxin and salicylic acid stimulated the production of oleoresin relative to commercial paste in at least one concentration. Replacement of CEPA with auxin or salicylic acid yielded equivalent oleoresin production, indicating a comparable or complementary effect of these molecules in the process, as well as having implications for new stimulant paste formulations.     

甘薯抗薯瘟病的水杨酸与活性氧的代谢变化

研究不同抗性甘薯品种受薯瘟病菌侵染后水杨酸(SA)和活性氧(ROS)的代谢变化.结果表明,感染薯瘟病菌12 h后甘薯叶片中SA含量增加,增加量与品种抗性呈正相关;接菌后过氧化氢(H2O2)含量增加,过氧化氢酶(CAT)活性下降,抗病品种变化幅度大于感病品种;接菌后抗病品种提高了与产生H2O2相关的酶过氧化物酶(POD)、超氧化物歧化酶(SOD)的活性,而感病品种与此相反,积累H2O2的能力下降,影响系统获得抗性(SAR)的建立.     

水杨酸对雕刻水仙的抗氧化系统的影响研究

为探求水杨酸对雕刻后水仙的抗氧化系统的影响,试验以不同浓度的水杨酸溶液对雕刻水仙叶片进行喷雾处理,结果发现不同浓度的水杨酸处理后均能提高叶片中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活力和类黄酮含量,降低过氧化物酶(POD)的活性和丙二醛(MDA)含量,使膜质透性(PMP)降低.     

外源水杨酸对Hg~(2+)胁迫下小麦幼苗生长及生理的影响

为了解水杨酸(SA)对Hg2+胁迫小麦幼苗生长的缓解作用,以小麦品种豫麦58号为材料,采用室内水培法分析了在Hg2+胁迫下小麦幼苗经不同浓度SA处理后的生长及生理变化。结果表明,外施SA能显著提高Hg2+胁迫下小麦幼苗的根长、株高、单株鲜重,叶片叶绿素、脯氨酸和可溶性蛋白含量,以及抗氧化酶活性和根系活力(P0.05),极显著降低丙二醛含量与超氧阴离子产生速率(P0.01)。说明外施SA可通过提高小麦幼苗可溶性蛋白和脯氨酸含量及抗氧化酶活性来维持细胞膜的稳定性,降低膜脂过氧化伤害程度,从而缓解了Hg2+胁迫对幼苗生长的抑制作用,其中以40mg·L-1 SA缓解效果最好。     

寡糖诱导向日葵抗锈病的信号转导途径

为了解寡糖诱导向日葵抗锈病过程中的信号转导途径,利用寡糖、水杨酸（SA）、茉莉酸（JA）预先喷雾处理向日葵叶片,1d后接种锈菌,通过对植株体内脂氧合酶（LOX）活性及SA含量的测定,并通过RT-PCR对SA、JA信号途径的标记基因PR5和PDF1.2等表达水平进行测定,初步确定诱导抗性表达的信号转导途径。结果表明：经寡糖诱导后,向日葵叶片内LOX活性降低,SA含量上升,且诱导水杨酸途径标记基因PR5表达量增加。结果说明寡糖诱导向日葵抵抗锈病主要与SA介导的信号途径有关。