不同缺素培养对玉米叶片脂质过氧化及保护酶活性的影响

主要以玉米品种金玉1号为试材,用水培法在苗期进行缺素（N、P、K、Ca、Mg、Fe）处理培养,缺素症状出现后对其生理指标进行测量,结果袁明：在不同缺素培养下玉米叶片的丙二醛（ⅧA）含量显著增加,产生的活性氧物质诱导超氧化物歧化酶（SOD）和过氧化物酶（POD）活性以及过氧化氢酶（CAT）活性下降,植株的叶绿素含量、蛋白质含量降低。     

外源钙对NaCl胁迫下西瓜幼苗生长的缓解效应研究

[目的]阐明外源钙对NaCl胁迫下西瓜幼苗生长的缓解效应.[方法]在向培养西瓜幼苗的营养液中添加100 mmol/L NaCl模拟盐胁迫的同时,添加CaSO4使Ca2+浓度分别达到4、6、10和14 mmol/L.处理10天后对西瓜幼苗的生长和生理指标进行测定,包括株高、茎粗、单株叶片数、植株最大叶的叶长和叶宽、鲜重、干重、丙二醛(MDA)含量、质膜相对透性、抗坏血酸(AsA)含量、游离脯氨酸含量、可溶性糖含量和可溶性蛋白含量等.[结果]100 mmol/L NaCl胁迫显著抑制了西瓜幼苗的生长,使叶片质膜透性、MDA含量显著增加,脯氨酸、可溶性糖、可溶性蛋白和抗坏血酸含量也不同程度增加;外源CaSO4可影响NaCl胁迫下幼苗的生长和生理指标,并有明显的浓度效应,其中6 mmol/L Ca2+处理显著促进了NaCl胁迫下幼苗的生长,使叶片质膜透性、MDA含量显著降低,脯氨酸、可溶性糖、可溶性蛋白和抗坏血酸含量显著增加.[结论]外源CaSO4可通过增强抗氧化能力和渗透调节能力,减轻胁迫造成的膜脂过氧化伤害,缓解NaCl胁迫对西瓜幼苗生长的抑制,且以6 mmol/L Ca2+处理的缓解效果最好.     

不同土层灌水对苹果幼苗抗氧化还原系统的影响

基于盆栽试验,研究了不同深度滴灌对植株膜伤害和抗氧化酶的影响。结果表明,自然干旱和2/3土层灌水处理叶片丙二醛和抗氧化酶活性较高,植株受旱;2/3土层供水、1/3土层供水和表层供水叶片丙二醛和抗氧化酶活性较自然干旱低,植株生长较好;同一处理灌水根区域的根系抗氧化酶活性较低。适宜苹果幼苗生长的灌水处理为表层供水和1/3土层供水。     

Introgressive hexaploid oats from the Avena abyssinica (♀) × A. sativa hybrid: performance, grain lipids and proteins

A fertile hexaploid oat plant was obtained after several generations of selection for seed set and plant type from a colchicine-produced decaploid hybrid, Avena abyssinica(2n = 4x = 28, AABB) × A. sativa (2n = 6x = 42, AACCDD). The selected line proved to be stably fertile and in many characteristics equal or superior to the hexaploid parent. The grain protein fractions showed two qualitative differences from those of the pollen parent and several differences from the maternal parent. The fractionating extraction used was new for oats. The fatty acid composition of grains of the hybrid derivative was similar to that of the pollen parent, but different from that of the maternal parent. The maternal parent (A. abyssinica) had a relatively high 16:0 fatty acid content (ca. 20.5 mol%) compared with the level of the hexaploid parent and the hybrid derivation (ca. 17.5 mol% each) in field-grown grain. However, in grain produced in the greenhouse, the hexaploids had ca. 20.5 mol% of 16:0 fatty acid and a decrease in 18:1 fatty acid, whereas seed of the A. abyssinica parent showed only a slight increase (ca.21.5 mol%) in 16:0 fatty acid. These and other responses statistically significant may be due to adaptation to temperature conditions being wider in the hexaploids than in the East-African A. abyssinica. A new method of grain lipid extraction was introduced and showed good reproducibility. The derived hexaploid oat can be crossed with A. sativa for breeding purposes and due to its early maturity might also have direct use in northern or high-altitude cultivation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physiological and Biochemical Responses of Hexaploid and Tetraploid Wheat to Drought Stress

An experiment was conducted to investigate the physiological and biochemical responses of two hexaploids viz., C 306 (water stress tolerant) and Hira (water stress susceptible), and two tetraploids, HW 24 (Triticum dicoccum) and A 9‐30‐1 (Triticum durum) wheat genotypes to water stress under pot culture condition. Water stress was imposed for a uniform period of 10 days at 50, 60 and 70 days after sowing (DAS) and observations were recorded at 60, 70 and 80 DAS. Total dry matter and plant height were recorded at harvest. Water stress caused a decline in relative water content (RWC), chlorophyll and carotenoid content, membrane stability and nitrate reductase activity and increased accumulation of proline at all stages and abscisic acid (ABA) at 80 DAS in all the genotypes. Both the tetraploids showed a lower reduction in RWC and highest ABA accumulation under water stress. Among the hexaploids Hira showed the most decline in RWC and the lowest ABA accumulation. The tetraploids also showed comparatively higher carotenoid content and membrane stability, closely followed by C 306, while Hira showed the minimum response under water stress. Nitrate reductase activity and chlorophyll content under irrigated conditions were highest in Hira but under water stress the lowest per cent decline was observed in C 306, followed by HW 24, A 9‐30‐1, and Hira. Proline accumulation under water stress conditions was highest in hexaploids C 306 and Hira and lowest in tetraploids HW 24 and A 9‐30‐1. Tetraploids HW 24, followed by A 9‐30‐1 maintained higher plant height and total dry matter (TDM) under water stress and also showed a lower per cent decline under stress than hexaploids C 306 and Hira. From the results it is clear that proline accumulation did not contribute to better drought tolerance of tetraploids than hexaploids. It is also apparent that water stress tolerance is the result of the cumulative action of various physiological processes, and all the parameters/processes may not be positively associated with the drought tolerance of a particular tolerant genotype.     

低温弱光对茄子幼苗某些生理指标的影响

研究了茄子幼苗在低温弱光（10℃/5℃ 昼/夜,光强60和120μmol/）胁迫和恢复各7d后的部分生理指标的变化。结果表明,低温弱光胁迫后茄子幼苗的净光合速率（Pn）,气孔导度(Gs)和叶绿素(Chl.)含量显著降低;光补偿点(LCP)、光饱和点(LSP)、光饱和时的Pn、表观量子效率(AQY)降低;CO2补偿点（CCP）升高,CO2饱和点（CSP）、CO2饱和时的Pn、光合能力（A350）、CO2羧化效率（CE）降低;POD和CAT活性明显下降;Pro.和MDA含量有不同程度的升高;均以低温下较强光照时（120μmol/）的变化幅度较大;恢复7d后除MDA含量基本恢复到对照水平外,其它各项指标仍然不能恢复到对照水平。试验条件已使茄子幼苗发生了膜脂过氧化作用,并对茄子幼苗叶片光合机构的结构和活性造成了不可恢复性的伤害。     

豆制品加工中黄浆水无害化处理技术研究

对豆制品中黄浆水进行超滤处理的工艺参数进行研究。用外加压管式膜组件对黄浆水进行了超滤试验,分析了液体分别在不同的温度、压力、流速、pH值等因素下对渗透流量和截留率的影响。通过正交试验,得到了处理黄浆水废液的最佳工况。实验结果表明,超滤处理黄浆水的最佳工况是:在压力0.15MPa下,用泵的最大流量对刚排放的黄浆水(温度55℃左右)进行超滤处理,可回收全部脂肪、75%以上的蛋白质和70%以上的总糖。回收后的浓缩物(或干燥物)可以作为饲料或经纯化后食用。     

Physicochemical, Structural and Textural Properties of Tortillas from Extruded Instant Corn Flour Supplemented with Various Types of Corn Lipids

The chemical composition and the components of corn grain affect the quality of tortillas produced from extruded instant corn flour (EICF). We have studied the effects of various types of corn lipids added at several concentrations to the regular raw corn flour before processing. The structural properties of flour, the effective moisture diffusion coefficient and the weight loss during cooking of fresh masa, as well as the textural characteristics of tortillas were analysed as a function of concentration and type of corn lipid added. The concentration of added lipid ranged from 0·5 to 2% (w/w). Each type and concentration of lipid was observed to have a different effect in the quality of masas and tortillas. Commercially it is desired to have tortillas with good properties and a high yield, that is, optimum weight transformation from corn to tortilla. From our analysis, the lowest dehydration rate (lowest effective moisture diffusion coefficient) and the best physicochemical and textural characteristics of fresh masas and tortillas were obtained from flour supplemented with 0·5% (w/w) of the nonpolar lipid fraction III. The loss in starch crystallinity due to the cooking process of masa into tortilla was similar in all treatments.     

Effect of Fucoidan on the Mitochondrial Membrane Potential (ΔΨm) of Leukocytes from Patients with Active COVID-19 and Subjects That Recovered from SARS-CoV-2 Infection

Fucoidan is a polysaccharide obtained from marine brown algae, with anti-inflammatory, anti-viral, and immune-enhancing properties, thus, fucoidan may be used as an alternative treatment (complementary to prescribed medical therapy) for COVID-19 recovery. This work aimed to determine the ex-vivo effects of treatment with fucoidan (20 µg/mL) on mitochondrial membrane potential (ΔΨm, using a cationic cyanine dye, 3,3′-dihexyloxacarbocyanine iodide (DiOC₆(3)) on human peripheral blood mononuclear cells (HPBMC) isolated from healthy control (HC) subjects, COVID-19 patients (C-19), and subjects that recently recovered from COVID-19 (R1, 40 ± 13 days after infection). In addition, ex-vivo treatment with fucoidan (20 and 50 µg/mL) was evaluated on ΔΨm loss induced by carbonyl cyanide 3-chlorophenylhydrazone (CCCP, 150 µM) in HPBMC isolated from healthy subjects (H) and recovered subjects at 11 months post-COVID-19 (R2, 335 ± 20 days after infection). Data indicate that SARS-CoV-2 infection induces HPBMC loss of ΔΨm, even 11 months after infection, however, fucoidan promotes recovery of ΔΨm in PBMCs from COVID-19 recovered subjects. Therefore, fucoidan may be a potential treatment to diminish long-term sequelae from COVID-19, using mitochondria as a therapeutic target for the recovery of cellular homeostasis.     

Antioxidative Effect of Chlorella Pyrenoidosa Protein Hydrolysates and Their Application in Krill Oil-in-Water Emulsions

Chlorella pyrenoidosa is an excellent source of protein, and in this research, we assessed the antioxidant and emulsifying effects of Chlorella protein hydrolysate (CPH) using neutral proteases and alkaline proteases, as well as the properties of CPH-derived krill oil-in-water (O/W) emulsions. The CPHs exhibited the ability to scavenge several kinds of free radicals, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), O₂⁻, hydroxyl, and ABTS. Additionally, the CPHs (5 mg/mL) scavenged approximately 100% of the DPPH and ABTS. The CPHs showed similar emulsifying activities to Tween 20 and excellent foaming activities (max FS 74%), which helped to stabilize the krill oil-in-water emulsion. Less than 10 mg/mL CPHs was able to form fresh krill oil-in-water emulsions; moreover, the CPHs (5 mg/mL) in a krill O/W emulsion were homogenous, opaque, and stable for at least 30 days. Based on their inhibitory effects on the peroxide value (POV) and thiobarbituric acid reactive substances (TRABS), the CPHs were found to be able to inhibit lipid oxidation in both emulsifying systems and krill O/W emulsions. Thus, the CPHs could improve superoxide dismutase (SOD) activities by 5- or 10-fold and decrease the high reactive oxygen species (ROS) level caused by the addition of H₂O₂ in vitro. In conclusion, health-promoting CPHs could be applied in krill oil-in-water emulsions as both emulsifiers and antioxidants, which could help to improve the oxidative and physical stability of emulsions.