油菜籽来源抗氧化物质研究进展

油菜籽中含有多种具有抗氧化活性的物质，为抵御机体的氧化损伤起到了积极作用。本文综述了油菜籽来源的诸多抗氧化活性成分及抗氧化活性的评价方法。油菜籽主要的抗氧化成分有肽类、多酚类、多糖类、生育酚和其它抗氧化成分，其中的肽类主要有三种产生方式：非消化酶酶解、消化酶酶解和发酵。针对油菜籽来源的活性物质抗氧化活性的评价方法，包括体外测定方法（化学检测）和细胞内抗氧化实验和动物实验。综述还探讨了油菜籽抗氧化活性成分研究中存在的问题和解决方法，旨在为油菜籽活性成分的开发和利用提供参考。     

非热处理对蜂花粉杀菌效果及品质的影响

为探究更有利于保留蜂花粉原有营养和风味的杀菌方法,本研究分别用辐照、超高压和高压静电场3种非热杀菌技术处理蜂花粉,并测定营养及风味的指标。结果表明,7 kGy辐照、500 MPa超高压、30 kV高场强处理对蜂花粉中的微生物均有抑制作用,且辐照对细菌的抑制效果较好,超高压和高压静电场对真菌的抑制效果较好。经500 MPa超高压处理后,蜂花粉脂类含量增加了23.3%,酚酸等活性成分含量增加,且其抗氧化活性降低程度最小,颜色和风味最接近未处理蜂花粉;30 kV高场强处理后,蜂花粉抗氧化活性显著下降、颜色偏深偏暗;7 kGy辐照处理后产生了明显的辐照味。综上,蜂花粉经超高压灭菌能达到较好的杀菌效果,而且能最大限度保持蜂花粉原有品质。本研究为非热杀菌技术在蜂花粉加工产业中的应用提供了理论依据。     

硅钙钾镁肥配施黄腐酸钾对土壤酶活性及桃幼树生长的影响

为探究硅钙钾镁肥配施黄腐酸钾对桃树生长的效应,以盆栽一年生瑞蟠21号毛桃(Amygdalus persica Linn.)为试验材料,设置3种不同施肥方式(T1:硅钙钾镁;T2:硅钙钾镁+黄腐酸钾;CK:空白对照),在桃幼树生长季进行追肥处理,研究硅钙钾镁肥及硅钙钾镁肥配施黄腐酸钾对土壤酶活性、土壤养分状况及桃幼树根系构型和植株生长的影响。结果表明,与CK相比,T1、T2均显著提高了桃幼树生长季各时期土壤酸性磷酸酶、脲酶和过氧化氢酶活性,以及土壤中碱解氮、有效磷、速效钾和有效硅等含量,且配施黄腐酸钾后作用更明显。与CK相比,T1、T2细根比重分别提高了11.2%和26.2%,根系活力分别提高了12.2%和18.1%,根系总长度分别增加了28.1%和61.9%,且有效延缓了根系衰老;T1、T2植株总干重分别提高了1.2倍和2.0倍,根冠比分别提高了9.4%和17.0%,且差异显著。与CK相比,T1、T2各器官中全氮、全磷、全钾含量均显著增加,地上部硅含量分别提高了61.3%和91.9%,地下部硅含量分别提高了62.3%和102.5%,且差异显著。同时,T1、T2桃幼树叶片叶绿素含量和净光合速率均显著提高。综上所述,硅钙钾镁肥可有效提高土壤酶活,促进桃幼树细根的生长,延缓根系衰老进程,增加氮、磷、钾、硅等营养元素积累量,提高叶片光合速率,促进植株生长;硅钙钾镁肥配施黄腐酸钾后,提高了土壤有效硅及植株硅含量,比单施硅钙钾镁肥效果更加显著。本研究结果为桃树合理施用硅钙钾镁肥提供了理论依据。     

60Co-γ射线和电子束辐照灭菌对葛根提取物抗氧化活性及指纹图谱的影响

为评价⁶⁰Co-γ射线和电子束辐照灭菌对葛根提取物品质的影响效应及其差异性,采用不同剂量的⁶⁰Co-γ射线(0、2.8、5.7、8.3、10.6 kGy)和电子束(0、2.4、5.1、7.7、10.3 kGy)辐照处理葛根提取物,研究辐照对其微生物总数、抗氧化活性及指纹图谱的影响。结果表明,⁶⁰Co-γ射线和电子束辐照均能有效降低葛根提取物中需氧菌总数、霉菌和酵母菌总数,随着吸收剂量增大,抑制作用增强。⁶⁰Co-γ射线和电子束辐照吸收剂量分别为5.7 kGy和5.1 kGy时,葛根提取物均达到《中国药典》所规定的微生物限度标准(需氧菌总数为10³ CFU·g^-1、霉菌和酵母菌总数为10² CFU·g^-1);吸收剂量分别为5.7 kGy和7.7 kGy时,需氧菌总数、霉菌和酵母菌总数均降至10 CFU·g^-1以下。此外,大肠埃希氏菌(Escherichia coli)与沙门氏菌(Salmonella)均未检出。2种辐照方式均对葛根提取物的DPPH自由基(DPPH·)清除率、羟自由基(·OH)清除率以及总还原能力无显著影响(P>0.05)。不同剂量⁶⁰Co-γ射线和电子束辐照处理葛根提取物特征峰的相似度达到1.0,且相对保留时间的相对标准差(RSD)均小于0.5%,表明2种辐照方式对葛根提取物指纹图谱均无显著影响(P>0.05)。综上所述,⁶⁰Co-γ射线和电子束辐照对葛根提取物微生物具有较强的抑制作用,2种辐照方式均不会对葛根提取物的抗氧化活性及指纹图谱产生显著影响,不影响葛根提取物的有效性及质量稳定性。该研究为2种辐照技术,特别是电子束辐照在葛根药材、饮片及其中成药制剂灭菌中的合理应用提供了科学参考。     

2种紫花苜蓿耐盐生理特性的初步研究

为研究2种紫花苜蓿(Medicagosativa L.)“阿迪娜”(耐盐基因型)和“秘鲁”(敏盐基因型)在盐胁迫处理下的生理特性与耐盐机理,采用150mmol/LNaCl胁迫处理2种紫花苜蓿幼苗,分别测定盐处理前和处理后2,4,6,8,16h的过氧化氢酶(CAT)、过氧化物酶(POD)、丙二醛(MDA)、脯氨酸(PRO)、相对含水量(RWC)和叶绿素(Chl)含量。结果表明:2种紫花苜蓿的过氧化氢酶活性、过氧化物酶活性和丙二醛含量在盐胁迫下总体呈上升趋势,脯氨酸含量和相对含水量表现出相反的趋势。叶绿素含量在盐胁迫前期稳定不变,但在胁迫后期显著性下降;2种紫花苜蓿的相对含水量和叶绿素含量的变化趋势与植株表型变化相对应。主成分分析表明,过氧化氢酶和丙二醛的贡献率最大,能更好地为苜蓿耐盐机理及分子育种研究提供理论依据。     

Soil physical changes and maize growth in a structurally fragile tropical soil due to mulching and duration between irrigation intervals

Under tropical meteorological conditions, the volume of soil explored by plant roots is crucial for crop growth as it allows increased water and nutrient use efficiency. We hypothesized that, under different irrigation intervals, leguminous mulch can extend the duration between irrigation events but maintain crop performance, because decreased evaporative fluxes also reduce constraints to root exploration imposed by mechanical stress. We evaluated the combined effects of leguminous mulch and irrigation intervals on soil physical properties to determine whether the growth and productivity of maize were modified in a structurally fragile tropical soil. The experiment involved the following treatments: 4‐day irrigation intervals with soil mulched (4C) or bare (4S), 6‐day irrigation intervals with soil mulched (6C) or bare (6S), 8‐day irrigation intervals with soil mulched (8C) or bare (8S) and 10‐day irrigation intervals with soil mulched (10C) or bare (10S). Mulch decreased soil penetration resistance and increased to 4 days the favourable time for root development in drying soil. Relative to bare soil, mulch with a 6‐day irrigation interval almost doubled nitrogen uptake post‐tasselling, which decreased nitrogen remobilization and increased the crop growth rate during this stage. These conditions had a positive effect on the transpiration rate and stomatal conductance as well as on the growth and yield of maize. A 6‐day irrigation interval with mulch compared to 4 days with bare soil resulted in similar conditions for root development, but greater uptake of nitrogen (102.73–78.70 kg/ha) and better yield (6.2–5.3 t/ha), which means greater efficiency in nitrogen and water use.     

果蔬籽油生物活性研究进展

果蔬籽油是由果蔬籽经压榨或萃取工艺制得的植物油脂。果蔬籽油含有丰富的维生素、多不饱和脂肪酸、有机酸等活性成分,这些成分赋予了果蔬籽油抗氧化、抗癌、调节血脂和调节免疫系统等生物活性。本文综述了果蔬籽油生物活性的研究进展,旨在为果蔬籽油的综合开发和利用提供理论依据和指导。     

Resistance monitoring and enzyme activity in three field populations of cowpea aphid (Aphis craccivora) from Egypt

The cowpea aphid (Aphis craccivora) is one of the most important sucking insect pests attacking certain legumes in Egypt particularly faba bean, cowpea and pea. In this study we monitored the resistance level of three field populations of A. craccivora to seven insecticides belonging to three different chemical classes (organophosphates, carbamates and neonicotinoids). The three populations were collected from three governorates in Egypt namely Dakahlia, Qalyobia and Beni Suef. Diagnostic concentrations (LC₉₀ values for susceptible strain) for each insecticide were established using a leaf dipping technique. Resistance monitoring showed that the field population from Dakahlia was highly resistant to all the tested insecticides. In a similar manner, the population from Qalyobia was also resistant to all insecticides except for fenitrothion to which only moderate resistance was observed. The field population from Beni Suef exhibited a lower level of resistance to all the seven tested insecticides.Biochemical assay showed that esterase activity in these three field populations was generally higher as the enzyme activity ratio ranged from 4.3 to 7.8 fold more than that for the susceptible strain. The activity of the other measured detoxifying enzymes (glutathione -S- transferase and mixed function oxidases) was moderate in the populations from Qalyobia and Dakahlia. Nevertheless, the enzyme activity in A. craccivora collected from Beni Suef was variable and differed slightly from the activity measured in the susceptible strain. Monitoring insecticide resistance among the three aphid populations was a proactive approach to detect any shift in insecticide efficiency. The possible occurrence of resistance in the cowpea aphid to the tested insecticides may be due to the higher activity of carboxylesterases. Further studies on the resistance mechanism to these insecticides are needed to provide insights in how to manage and delay the onset of the resistance and thus prolong the performance of insecticides against A. craccivora.     

一株大豆内生拮抗细菌XZ-2的分离和分子鉴定

从大豆植株中分离到一株具有广谱抗菌活性的拮抗细菌,命名为XZ-2。抑菌活性测定显示XZ-2对甘薯黑斑病菌、大蒜叶枯病菌等8种植物病原真菌均具有较强的抑菌活性,抑菌直径均在20 mm以上。采用分光光度法绘制了XZ-2的生长曲线,结果显示该菌株在LB液体摇培12 h时基本达到对数生长期,该生长曲线的绘制为后期XZ-2的活性物质发酵条件优化奠定了基础。通过PCR扩增16Sr DNA片段并采用MEGA 6.0构建系统发育进化树,初步将该菌株鉴定为多粘类芽孢杆菌。     

土壤温度对作物根区环境及玉米根冠生长的调控研究进展

土壤温度对作物的生长发育具有很强的调控作用。在全球气候变化背景下,根区土壤温度对玉米生长的影响及其调控机制已成为当前研究的一个热点。结合目前农业生产中土壤低温和高温对玉米造成危害的现状,从土壤温度对作物根区土壤环境以及玉米根系生长、冠层发育与产量形成的影响方面,综述土壤温度对玉米生长发育调控作用的研究进展,介绍改变土壤温度的措施以及对玉米土壤温度研究的发展方向进行展望,为今后的研究提供参考。