微波处理对赤拟谷盗各虫态的致死效果研究

分别采用微波功率160、320、480、640和800 W处理裸露的和混合于小麦粉中的各虫态赤拟谷盗Tribolium castaneum (Herbst)的卵、幼虫、蛹和成虫。结果表明：对于裸露的赤拟谷盗用上述功率各处理5、10、15、20、25和30 s时,800 W、25 s可完全致死卵,320 W、30 s可使幼虫和成虫完全致死;800 W、20 s可完全致死幼虫、蛹和成虫。对混合于小麦粉中的各虫态赤拟谷盗,当用上述功率各处理20 s时,均不能完全致死各虫态;单独使用800 W分别处理5、10、15、20和25 s时,仅800 W、25 s可完全致死各虫态。微波处理对赤拟谷盗杀虫效果显著。     

微波处理对赤拟谷盗各虫态的致死效果

分别采用微波功率160、320、480、640和800W处理裸露的和混合于小麦粉中的各虫态赤拟谷盗Tribolium castaneum(Herbst)的卵、幼虫、蛹和成虫。结果表明:对于裸露的赤拟谷盗用上述功率各处理5、10、15、20、25和30s时,800W、25s可完全致死卵,320W、30s可使幼虫和成虫完全致死;800W、20s可完全致死幼虫、蛹和成虫。对混合于小麦粉中的各虫态赤拟谷盗,当用上述功率各处理20s时,均不能完全致死各虫态;单独使用800W分别处理5、10、15、20和25s时,仅800W、25s可完全致死各虫态。微波处理对赤拟谷盗杀虫效果显著。     

稻米仓储害虫的微波致死作用研究

以米象和锯谷盗为对象,研究微波作用对稻米害虫的致死作用,探索适宜的微波杀虫条件.结果表明微波条件对米象和锯谷盗成虫和虫卵致死率有极显著影响,对虫卵致死率的影响较成虫显著.在微波参数中,对米象致死率的影响以能量密度最大,其次是时间和能耗.在相同微波处理条件下,虫卵致死率大于成虫致死率.在较高能量密度下,米象致死的能耗较高,100%致死的能耗为6.0×10-5kW·h/g以上.在较低能量密度下,米象100%致死的能耗为3.0×10-5kW·h/g以上.较低能量密度和稍长时间的微波处理有利于害虫的杀灭,且能耗较低.     

微波处理对醉马草内生真菌的杀灭效果及发芽活力的影响

为探索构建禾草内生真菌不感染试验种群的方法,选用醉马草为材料,以150W和300W微波功率分别处理醉马草种子30、40、50和60s,研究不同微波处理强度下内生真菌的致死情况,同时考察微波对醉马草发芽活力的影响。结果表明,150W和300W处理40s以上,醉马草带菌率分别显著降到19.38%、5.22%以下,300W处理60s,醉马草内生真菌可完全致死;150W处理30、40s和300W处理30s后,醉马草的发芽率、发芽势、发芽指数和活力指数与对照(未经微波处理,CK)相比均无显著差异,其他处理下上述指标随处理强度的增加出现不同幅度的下降;150W或300W处理30s和40s的醉马草芽长、根长和生物量与CK无显著差异,其他处理下各指标均受到不同程度的抑制。因此,150W处理40s为剔除醉马草种传内生真菌的最佳方法。本研究为探索无毒醉马草作为饲料及优良牧草的选育提供了技术支持。     

核桃青皮中多元酚类化合物的提取及含量分析

核桃在采摘及加工过程中产生的青皮遗弃物处理已经成为一个社会问题。以核桃青皮为原料,经酶解、微波超声波辅助处理后获得多元酚类化合物提取液,检测化合物中没食子酸、原花青素和儿茶素的含量。结果显示,固料比1∶4,1%复合提取酶、温度为50℃、p H6.0下恒温振荡12 h;微波超声波萃取仪处理15 min,分3阶段,每阶段5 min。(丙酮为萃取剂,液液比1∶6,设置温度分别为50℃、60℃、70℃;超声波功率分别为800 W、900 W、1 000 W;微波功率分别为100MHz、200 MHz、300 MHz;超声波频率恒定为25 k Hz,转速1 000 r/min);加4%明胶产生沉淀后分别氯仿、乙酸乙酯萃取获得鞣质提取液提;分别检测到没食子酸的含量为1.125 mg/g,原花青素的含量为1.71 mg/g,儿茶素的含量为0.035 mg/g。     

核桃青皮中多元酚类化合物的提取及含量分析

核桃在采摘及加工过程中产生的青皮遗弃物处理已经成为一个社会问题。以核桃青皮为原料,经酶解、微波超声波辅助处理后获得多元酚类化合物提取液,检测化合物中没食子酸、原花青素和儿茶素的含量。结果显示,固料比1∶4,1%复合提取酶、温度为50℃、p H6.0下恒温振荡12 h;微波超声波萃取仪处理15 min,分3阶段,每阶段5 min。(丙酮为萃取剂,液液比1∶6,设置温度分别为50℃、60℃、70℃;超声波功率分别为800 W、900 W、1 000 W;微波功率分别为100MHz、200 MHz、300 MHz;超声波频率恒定为25 k Hz,转速1 000 r/min);加4%明胶产生沉淀后分别氯仿、乙酸乙酯萃取获得鞣质提取液提;分别检测到没食子酸的含量为1.125 mg/g,原花青素的含量为1.71 mg/g,儿茶素的含量为0.035 mg/g。     

微波预处理原料对苹果汁褐变的影响

为了防止苹果汁在贮藏过程中褐变,采用不同的微波功率和时间预处理原料苹果,研究微波预处理对苹果汁褐变的影响。结果表明,微波处理可以提高苹果汁的色值,降低多酚氧化酶的活性,引起氨基态氮含量的下降,并使苹果汁的酸度略微提高。在微波功率为720～900 W,处理时间75～125 s时,果汁色值较高。室温贮存45 d后,微波功率900 W,时间为100 s处理的果块,果汁色值为67.8,比未经微波处理的高91.5%。微波预处理是防止苹果汁褐变的一种简便安全、合理经济的加工方法。     

糖姜间歇微波真空干燥特性及其动力学模型

为了探讨避免糖姜焦糊的微波真空干燥模式,该文以湿糖姜为原料,研究真空度、功率质量比及姜块的体积对糖姜间歇微波真空干燥速率及品质的影响,建立糖姜干燥动力学模型。结果表明：糖姜采用间歇式微波真空干燥技术,能避免焦糊和褐变的发生,适宜微波加热和间歇时间分别为30和90?s,功率质量比为10～?15?W/g,真空度为-80?kPa;糖姜微波真空干燥的动力学满足指数模型,该模型能很好预测微波真空干燥过程中糖姜含水率随干燥时间、比功率、真空度和姜块体积的变化关系,试验结果为实现糖姜的可控制工业化干燥提供技术依据。     

微波预处理对玉米秸秆的组分提取及糖化的影响

为了分离得到玉米秸秆中的半纤维素、木质素,改善纤维素的酶水解可及性,对玉米秸秆进行了二步微波预处理法研究.考察了秸秆粒径、液固比、碱及甘油用量、微波功率与处理时间对半纤维素和木质素得率的影响;探讨了预处理后秸秆的酶水解性能.得到的优化预处理条件为:玉米秸秆粒径40～80目;微波-碱预处理功率116.7 W/g、时间10 min、液固比20 mL/g、碱用量150％(质量分数);微波-甘油预处理功率66.7 W/g、处理时间30 min、液固比20mL/g、甘油质量分数100％.试样结果表明:经微波预处理后每10 g玉米秸秆最终可得到2.48 g半纤维素、0.95 g木质素,3.55 g还原糖;二步微波预处理不仅能够提取出玉米秸秆中的半纤维素、木质素,而且提高了纤维素水解的酶可及性,实现了组分的分离.     

不同虫态米象侵害对小麦蛋白理化和结构特性的影响

为探索不同虫态米象侵害对小麦蛋白品质的影响，该研究以米象侵害后的小麦为研究对象，对米象不同虫态（卵期、幼虫期、蛹期、成虫期）侵害后的小麦粗蛋白、尿酸、蛋白组分、湿面筋、面筋吸水量、乳酸溶剂保持力（solvent retention capacity，SRC）、蔗糖SRC、巯基（-SH）、二硫键（-S-S-）、蛋白质二级结构、面筋蛋白显微结构以及制成全麦面条的色泽和质构特性等进行测定与分析。结果表明，米象的侵害会使小麦蛋白的理化特性和形态结构变差。随着米象的生长发育，小麦籽粒中粗蛋白的含量显著上升，湿面筋、面筋吸水量，乳酸SRC、蔗糖SRC，- SH和- SS -的含量下降，小麦蛋白组分和二级结构比例发生显著变化(P<0.05)，小麦的食用品质和营养价值降低。面筋蛋白显微结构显示：随着米象在小麦籽粒内部生长发育，面筋表面粗糙程度加重，断裂面和毛刺增多，到达成虫期后，部分面筋结构已经严重断裂，无法识别。制成全麦面条后，面条的色泽加深，L*值、蒸煮损失率增大，a*值、b*值、硬度、黏附性、弹性、内聚性、咀嚼性和回复性降低。该试验结果进一步阐明了米象侵害后小麦品质的劣变机制，为小麦贮藏期间及虫蚀小麦的品质改良提供了一定的理论基础。     

Determining tolerance limits for restoration and phytoremediation with Spartina patens in crude oil-contaminated sediment in greenhouse

Oil spills may detrimentally damage sensitive coastal habitats, such as coastal wetlands. Successful restoration of oiled habitats primarily depends on the tolerance of vegetation transplants to oil. In this study, tolerance limits of the dominant coastal brackish marsh plant Spartina patens to South Louisiana crude (SLC) oil and its phytoremediation effectiveness on petroleum hydrocarbons in wetland sediments were investigated in the greenhouse environment. Spartina patens was transplanted into brackish marsh sediments contaminated with SLC oil at concentrations of 0, 40, 80, 160, 320, 640 and 800 mg SLC oil g^?1 dry sediment. High oil concentrations adversely affected plant stem density, aboveground biomass and belowground biomass even one year after transplantation. At the 320 mg g^?1 oil dosage, plant belowground biomass was significantly lower than the control although aboveground variables were not significantly different from the control. All plant parameters mentioned above at the 640 mg g^?1 oil dosage were less than 50% of the control. Spartina patens did not survive the 800 mg g^?1 oil dosage. The tolerance limit of S. patens to SLC was estimated about 320 mg oil g^?1 dry sediment. In addition, S. patens transplants enhanced oil degradation in the sediment; concentrations of residual total petroleum hydrocarbons (TPH) in the sediments vegetated by S. patens were significantly lower than those of un-vegetated sediments for both the surface and subsurface sediment at the 40 and 160 mg g^?1 SLC oil dosages. Decreases in the concentrations of polycyclic aromatic hydrocarbons (PAHs) further demonstrated the capacity of S. patens to phytoremediate residual oil; residual total targeted PAHs in the phytoremediation treatment were less than 20% of the un-vegetated treatment at the 40 mg g^?1 oil dosage. These results demonstrated the potential of phytoremediation with S. patens to simultaneously restore and remediate petroleum-contaminated coastal marsh habitats.     

Salinity and Temperature Effects on Seed Germination of Milk Thistle

Abstract

Milk thistle [Silybum marianum (L.) Gaertn] is an annual plant belonging to the Asteraceae family whose ripe seeds contain flavonoid substances, which are important in the modern pharmaceutical industry. Seed germination is a major factor limiting the establishment of plants under saline conditions. The effect of salinity and temperatures on germination and seedling establishment was studied in two genotypes of milk thistle, an Iranian wild type and German (Royston) type in the laboratory and in the field. Experiments were done with seven salt concentrations [0.1 (control), 1, 3, 6, 9, 12, and 15 dS/m] and three temperatures (15, 25, and 35°C). There were three replications for each treatment, and the experiment was run three times. The results showed that the percentage of germination and the number of normal seedlings at different salt treatment at 15°C were higher than at 25 or 35°C. The mean time to 50% germination was least at this temperature for both genotypes. Results suggested all germination indices and seedling emergence (50%) were achieved at levels up to 9 dS/m salinity at 15°C. Also, seeds at a salinity of 9–15 dS/m will germinate and up to 25% of the control nonstress treatment could emerge at the low temperature of 15°C.     

Oxygreen process applied on nongerminated and germinated wheat: role of hydroxamic acids

Wheat samples were taken at different stages of germination characterized by their falling number (which is a relevant indicator of germination) from 400 to 60 s. Each batch was treated by the Oxygreen process, a treatment by ozone, in a closed sequential batch reactor. Leucotriene B4 (LTB 4) was induced by germination, but ozone treatment did not increase this effect. Extract obtained from these wheat batches was applied on human epithelial bronchial cells. Wheat extract from nongerminated wheat did not induce any DNA adduct. More the wheat germination gets underway, more DNA adducts are observed. In contrast, germination did not affect the cell viability. Ozonization of wheat exemplified genotoxic effects only if the wheat was germinated. The implication of hydroxamic acids is discussed. In conclusion, ozonization of wheat, of high milling quality, does not pose any problem.     

Enhanced Lipid Stability in Whole Wheat Flour by Lipase Inactivation and Antioxidant Retention

The purpose of this study was to determine the effectiveness of dry heat, steam, and microwave treatments in decreasing lipase activity, while retaining antioxidant activity, to stabilize whole wheat flour against lipid degradation during storage. Bran was heat‐treated in 230‐g batches using four levels (exposure times) for each of the three treatment methods. Lipase activity and antioxidant activity were quantified for all treatment combinations. None of the treatments significantly decreased antioxidant activity; the levels determined to be optimal, inasmuch as further heating did not significantly decrease lipase activity, were 25 min of dry heat, 60 sec of microwave (1000W), and 60 sec of steam. These treatments effectively decreased lipase activity by 74, 93, and 96%, respectively. Optimum treatments were evaluated for acceptance using a consumer sensory panel during a 12‐month storage period. No significant differences in acceptance were found between the control and any of the samples either at baseline or after storage. This suggests that whole wheat flour can be stabilized against lipolysis by utilizing the treatments described in this study without decreasing antioxidant activity, and that manufacturers may utilize these treatments without risking decreased consumer acceptance.     

Comparative effects of propylene oxide,sodium azide,and autoclaving on selected soil properties

Samples of soil (25 g) were treated with 1 or 2 ml of propylene oxide, 400 or 800 parts/10⁶ of sodium azide, or autoclaved for 1.5 or 3.0 h. Soil sterilization was achieved by the propylene oxide and autoclaving treatments. Sodium azide inhibited the bacteria and actinomycetes and drastically reduced the fungal population. The autoclaving treatment decreased the soil pH 0.2 unit, while propylene oxide and sodium azide treatments increased it 0.5–1.1 units. Extractable manganous—Mn was increased 2- to 3-fold by all treatments except for a 90- to 120-fold increase in an autoclaved soil; extractable Ca was not affected; and the extractable K changes were slight. Total extractable N was increased 10–20 parts/10⁶, and available P was generally increased by the treatments. Propylene oxide induced the least chemical alterations upon sterilization and is considered an appropriate sterilant to study chemical transformations in soils; but, germination and growth of wheat and alfalfa were retarded in propylene oxide treated soil.     

减氮节水对宁夏引黄灌区春小麦光合特性与产量的影响

针对宁夏引黄灌区春小麦生产中氮肥投入过量及水资源利用效率低的问题,探究减氮背景下节水灌溉对春小麦群体动态、光合特性及产量的影响。2021年以宁春4号为供试材料,分别设置3个施氮水平（常规施氮270 kg/hm2、减施氮肥25%和不施氮）和3个灌溉定额（常规灌溉400 mm、节水20%和节水40%）。结果表明：1）同一氮肥水平下不同灌溉处理的群体总茎数均无显著性差异;同一灌溉定额水平下常规施氮和减氮水平处理的群体总茎数均显著高于不施氮处理,但二者无显著差异,减氮节水处理亦能维持较高的群体总茎数和茎蘖成穗率。2）与常规施氮相比,减氮25%对春小麦的生长发育无明显影响,在此基础上节水20%并不会降低春小麦株高,叶面积的生长,不会减少春小麦干物质累积量。3）减氮水平与常规施氮处理的春小麦叶片SPAD值和光合指标无明显差异,减氮水平下节水20%处理的叶片SPAD值和光合指标同常规灌溉无显著差异,但显著高于节水40%处理。4）所有水氮处理中减氮水平下20%节水处理的穗粒数和千粒质量最高,春小麦产量达8 092.52 kg/hm2,与常规施氮常规灌溉处理的产量无显著差异。减氮25%节水20%处理的灌溉施肥模式,既可获得较高产量又可以节约水氮资源,达到了宁夏引黄灌区春小麦生产中减氮、节水、稳产的目的。因此,可作为当地适宜的施氮灌溉方案。     

小麦微波干燥特性及其对品质的影响

针对小麦热风干燥中存在的问题，运用微波试验装置，通过选择不同的干燥功率、物料铺放厚度及排湿风速，研究了小麦微波干燥特性及其对干后品质和能耗的影响。研究结果表明：小麦微波干燥主要处于恒速阶段，微波干燥对小麦品质有显著的影响，小麦籽粒的发芽率和SDS沉降值对微波处理的反应比较敏感，可以作为小麦热损伤的指标和小麦品质变化的检测指标，小麦微波干燥能耗主要受排湿风速影响。     

介质阻挡放电低温等离子体处理对小麦种子活力及幼苗生理的影响

为揭示低温等离子体处理对小麦种子活力及幼苗生理特性的影响,该研究以济麦22、百农307为处理对象,对其进行不同时长（0、6、9、12、15 s）的介质阻挡放电（dielectric barrier discharge,DBD）低温等离子体处理,分析其对小麦种子萌发、幼苗生长、种皮形态结构、幼苗代谢生理及抗氧化性指标的影响。结果表明：以氩气为气源的DBD低温等离子体处理明显提高了小麦种子发芽率及其幼苗根苗长、鲜干重、活力指数;各处理时长条件下小麦种子吸水率均有所增加,当处理时间为9 s时,两种小麦种子的吸水率增幅最大,分别显著增加了6.4%（济麦22）、5.9%（百农307）（P<0.05）;小麦种子接触角随处理时间的延长而逐渐减小,表明其润湿性能逐渐提高;处理9 s时小麦的种皮结构组织轮廓模糊,呈现明显裂纹;处理后小麦种子的新生幼苗中光合色素含量、可溶性蛋白含量均得到不同程度的增加;处理后小麦种子的新生幼苗抗氧化能力有所提高,当处理时间为9 s时,两种小麦幼苗中的丙二醛含量降幅最大,分别显著降低了15.6%（济麦22）、18.0%（百农307）（P<0.05）。因此,DBD低温等离子体有效改善了小麦种子活力及其幼苗生理特性,可作为潜在的种子强化方法用于提高作物生产中的种子质量及促进后续小麦生长。     

增强紫外线-B辐射冬小麦产量和光合特性的影响

为了研究紫外线-B（ultraviolet-B UV-B, 280-320nm）辐射增强20%对保护性耕作冬小麦产量及光合特性的影响,在中国南京开展了2 a的田间试验研究。试验采用常规耕作（耕深25 cm）、少耕（耕深10 cm）和免耕（土壤不耕作）3种耕作处理种植冬小麦,采用人工增加紫外辐射的方法模拟UV-B辐射增强。试验测定了冬小麦旗叶的光合速率、光合-光响应曲线、叶绿素质量分数、超氧化物歧化酶（superoxide dismutase, SOD）活性、丙二醛（malonaldehyde, MDA）质量分数和可溶性蛋白质量分数等指标。结果表明：在UV-B辐射增强20%条件下,与常规耕作相比,少耕和免耕2种保护性耕作处理可显著提高冬小麦的产量,分别比常规耕处理作高1632.12和952.15 kg/hm2。从叶片光合生理特性来看,在UV-B辐射增强20%条件下,从冬小麦籽粒灌浆中期开始,少耕和免耕处理旗叶的光合速率、表观量子效率（apparent quantum yield, AQY）、最大净光合速率（Pmax）、叶绿素质量分数、SOD活性、可溶性蛋白质的质量分数显著高于常规耕作处理,MDA质量分数显著低于常规耕作处理,2种处理冬小麦的叶片衰老显著低于常规耕作处理。在UV-B辐射增强20%条件下,少耕和免耕2种保护性耕作处理冬小麦旗叶在籽粒灌浆中期及以后保持高的光合能力和低的衰老程度,是其产量高于常规耕作处理的原因。该文可为制定UV-B辐射增强条件下的冬小麦栽培措施提供参考。