谷子秸秆剪切力与其饲料营养特性变化规律及相互关系

为探究谷子秸秆力学性质与其饲料特性的变化规律及相互关系，选用谷物完熟期的谷子秸秆，将其分为5段（近根部、中下部、中部、中上部、上部）并每隔7 d进行秸秆节间、茎节力学性质（剪切、压缩）和饲料特性（形态指标、营养成分）测定。试验结果表明：谷物完熟后，随着时间的推进，秸秆节间、茎节剪切力、抗压强度、干物质含量、纤维素含量、半纤维素含量和木质素含量总体上呈增大趋势，而秸秆含水率、当量直径、横截面积、线性密度和粗蛋白含量总体上呈减小趋势。谷子秸秆单位直径剪切力与含水率和线性密度呈负相关关系（R2≥0.903），与其干物质、纤维素、半纤维素和木质素含量呈正相关关系（R2≥0.845），与其粗蛋白含量无显著相关关系（P>0.05）。采收期内，谷子秸秆基部起秸秆剪切力至顶部逐渐增大，且剪切力与当量直径、横截面积呈正相关关系（R2≥0.916）。试验表明谷子秸秆饲料特性指标验证试验值与预测值相对误差不大于6.48%，预测模型合理。测量秸秆剪切力可用于预测其形态指标参数和营养成分含量，进而一定程度地反映秸秆饲用价值和反刍动物择食趋向。采收期内，谷子中部及以上秸秆单位直径剪切力显著小于其近根部（P<0.05），更适合饲用；且谷物完熟后，及时采收可避免秸秆饲用价值降低。该研究可为高效利用谷子秸秆资源提供参考。     

不同外援营养液对白灵菇生长的影响

以白灵菇菌株TN01为试材,选取香菇、杏鲍菇、白玉菇3种食用菌菇根为原料配制外援营养液,测定各营养液主要成分含量,并研究了不同类型与浓度营养液对白灵菇菌丝及子实体生长的影响,以期为白灵菇的高产栽培技术提供参考依据。结果表明:与常规PDA培养基相比,适量加入白玉菇菇根提取液可提高白灵菇菌丝生长速度;添加外援营养液对子实体的农艺性状影响不大,对产量有一定的促进作用,其中施用香菇菇根提取液的白灵菇子实体产量最高,小区总产量与对照相比提高了54.6%。施用香菇菇根提取液后对白灵菇子实体中的硝酸盐含量及蛋白质含量有提升的效果,但对亚硝酸盐及粗纤维含量无促增长的效果。     

真空复合轧制自磨锐割刀与其结合界面组织性能研究

采用真空复合轧制工艺，将3种钢板（GCr15、Q420、IF）轧制成梯度复合材料，对其结合界面处的微观组织、成分及硬度分布、抗剪强度进行了检测，并对梯度材料自磨锐割刀进行了田间试验。结果表明，不同板层界面处材料间相互咬合形成较为紊乱的冶金结合方式，界面处元素相互扩散形成过渡区，组织缺陷较少。结合界面处的抗剪强度均超过了国标要求，且断裂方式为韧性断裂，不同界面间存在较为平缓的硬度梯度变化。梯度材料自磨锐割刀后刀面、刀尖及刃口材料为GCr15钢，硬度高、耐磨性好，前刀面的硬度呈梯度变化，磨损均匀，作业过程中可始终保持刀尖前凸，刃口曲率半径变化较小，能够长时间保持刃口的锋锐性与再生作物的低损伤切割。田间试验结果表明，相同作业条件下，梯度材料自磨锐割刀耐磨性是市售割刀的3倍以上。     

四川省犍为县越冬代稻显纹纵卷叶螟冬后虫口密度和生物学特性

稻显纹纵卷叶螟Cnaphalocrocis exigua(Butler)是稻纵卷叶螟Cnaphalocrocis medinalis(Guenée)的近缘种,目前主要在我国西南稻区发生为害。为了明确稻显纹纵卷叶螟在四川省犍为县冬后的虫源状况,我们开展了稻显纹纵卷叶螟冬后虫源结构调查,观察了冬后种群的生物学特性,并研究了温度对其的影响。结果显示,犍为县舞雩乡和罗城镇稻显纹纵卷叶螟冬后虫源密度分别为7.09头/25丛和5.50头/25丛。调查时稻显纹纵卷叶螟主要以蛹为主,有少量幼虫。稻显纹纵卷叶螟越冬代雌雄蛹重分别为11.56 mg和11.82 mg,性比(雌∶雄)为1.29∶1,蛹被寄生率为16.5%。20℃、22℃、24℃和室温下稻显纹纵卷叶螟越冬代蛹羽化率分别为44%、38%、52%、43%。不同温度下,稻显纹纵卷叶螟产卵量及成虫寿命无显著差异。本研究结果对于开春稻显纹纵卷叶螟的防控具有指导意义。     

释放巴氏新小绥螨防治温室大棚番茄上的烟粉虱

烟粉虱是一种世界性重大害虫,随着杀虫剂的抗药性问题以及在蔬菜上的残留问题日益严重,生物防治成为解决这一问题的重要措施。本文研究了释放巴氏新小绥螨对温室大棚番茄上自然发生的烟粉虱种群的控制作用。结果表明:释放巴氏新小绥螨,对温室大棚番茄上的烟粉虱的种群具有明显的压制作用;温室大棚番茄上烟粉虱种群,在释放捕食螨和常规对照处理间的总体动态趋势相同,烟粉虱的数量在番茄植株上的分布均为上部中部下部叶片,但常规对照处理的烟粉虱数量是释放捕食螨处理的2～3倍;在烟粉虱种群密度低时,释放巴氏新小绥螨的防治效果较好,达到90%以上,随着烟粉虱密度的增大,巴氏新小绥螨对烟粉虱的防治效果下降,但番茄拉秧时防效仍可达到55.70%。相比化学农药,释放巴氏新小绥螨的生物防治措施对治理烟粉虱更具有稳定性和长效性的优势。     

夜蛾黑卵蜂雌雄蜂鉴别方法及雌蜂寄生草地贪夜蛾卵的行为特征

夜蛾黑卵蜂Telenomus remus被认为是草地贪夜蛾Spodoptera frugiperda卵期的高效寄生蜂。明确夜蛾黑卵蜂基本生物学特征将为其繁育及应用提供重要参考。本研究对雌、雄蜂外部形态及雌蜂寄生行为进行了观察。结果显示,1、除雌蜂产卵器和雄蜂外生殖器等第一性征外,夜蛾黑卵蜂雌、雄蜂个体还具备一些典型的第二性征,可通过触角环节数量、触角棒节和柄节形态以及足和触角的颜色进行区分。2、在同一卵块上,雄蜂先于雌蜂羽化,并撕咬寄主卵壳协助雌蜂羽化;雌蜂羽化后雄蜂会立即求偶并与其交配。3、夜蛾黑卵蜂雌蜂通过利用寄主卵表鳞毛空隙、主动清理鳞毛和移动表层卵粒3种行为策略实现对大部分草地贪夜蛾卵的寄生。本研究建立了夜蛾黑卵蜂雌、雄蜂的鉴别方法,并明确了雌蜂应对夜蛾黑卵蜂卵表结构防御的行为策略。     

Urban land-use impacts on composition and spatiotemporal variations in abundance and biomass of earthworm community

Soil fauna can sensitively respond to alterations in soil environment induced by land-use changes.However,little is known about the impact of urban land-use changes on earthworm communities.In this study,three land-use types(i.e.,forest,nursery and abandoned lands)were chosen to identify differences in diversity,abundance and biomass of earthworm community in Kunming City.Urban land-use had a pronounced difference in species composition,evenness and diversity of earthworm communities.Forest land had the highest density,biomass and diversity of the earthworm communities.Total abundance was dominated by endogeic species in nursery land(70%)and abandoned land(80%),whereas in the forest land,the earthworm community comprised epigeic,endogeic and anecic species.Temporal changes in earthworm density and biomass were also significantly affected by land-use change.Total density and biomass of earthworms in the forest and nursery lands were highest in September,but highest in the abandoned land in October.The influence of soil physicochemical properties on the earthworm density and biomass also varied with land-use types.Soil temperature significantly affected earthworm density and biomass in the three land-use types.Soil pH was positively correlated with earthworm biomass in the forest land,but negatively associated with earthworm density in the abandoned land.Soil organic matter was positively correlated only with density and biomass of earthworms in the nursery and abandoned lands.Our results suggest that the species composition,abundance and biomass of earthworm communities can be determined by the modification of soil properties associated with urban land-use type.     

沙柳多元醇液化产物流变性能的研究

沙柳木粉在液化剂和催化剂的作用下制成的液化产物可生产制作聚氨酯、环氧树脂、胶黏剂等。研究沙柳液化产物的流变性能,可探索宏观流变性质与液体微观内部反应机理之间的关系,优化设备结构和加工工艺条件,对其高效利用有着重大意义。本试验将沙柳木粉在浓硫酸催化条件下进行多元醇液化,通过改变液化处理条件(反应时间、反应温度和催化剂用量)制备具有不同流变性能的沙柳液化产物。利用旋转型流变仪对所制备的沙柳液化产物进行流变性能测试和分析。沙柳木粉液化条件的单因素试验和正交试验分析结果表明:影响沙柳液化产物黏度的主要因素是反应时间,其次是反应温度和催化剂用量,最佳工艺条件为反应时间70 min、反应温度170℃、催化剂用量5%。在最佳工艺条件下,剪切速率为78.87 s-1时,黏度为0.26 Pa·s。红外光谱(FT-IR)分析得出,液化物中纤维素被大量降解,半纤维素和木质素部分降解,羟基增加,生成更多的反应活性官能团,此条件下液化反应更加充分,流体黏度较大。流变性能测试结果显示:稳态扫描测试时,黏度随剪切速率的增加逐渐减小,表现出剪切变稀的现象;剪切应力随着剪切速率的增加逐渐升高,表现出假塑性流体的性质。通过动态频率扫描曲线变化规律分析,储能模量和损耗模量随着角频率的升高而逐渐增加,复数黏度却随之减小。     

Properties of Edible Films Made From Anchovy By-Product Proteins and Determination of Optimum Protein and Glycerol Concentration by the TOPSIS Method

In the present study, the physicochemical and mechanical properties of films made from anchovy (Engraulis encrasicholus) by-product proteins (ABPs) were characterized as a function of protein (3, 4, and 5%) and glycerol (30, 40, 50, and 60%) concentration. In particular, the thickness, color, transparency, water vapor permeability (WVP), solubility, oxygen permeability (OP), and mechanical properties of the films were measured, and generally, these properties were affected by both protein and glycerol concentration. The thickness, redness, WVP and solubility values of films increased, while their lightness and yellowness values decreased as protein concentration increased. Furthermore, lightness, yellowness, and elongation at break (EAB) values were found to increase at higher glycerol concentrations within ABP films, whereas tensile strength (TS) and elastic modulus (EM) values decreased. ABP films became more transparent with increase of glycerol concentration and decrease of protein concentration. The OP values of all films decreased depending on protein and glycerol concentration. The techniques for order performance by similarity to ideal solution (TOPSIS) method was used to determine optimum protein and glycerol concentrations. According to this method, an edible film containing 4% protein and 40% glycerol was the best film with a C value of 0.6665.     

Sorghum extrusion process combined with biofortified sweet potato contributed for high iron bioavailability in Wistar rats

This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n = 7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES + SP group showed higher (p < 0.05) expression of DcytB, ferroportin and hephaestin when compared to the control group. The DS group showed high (p < 0.05) expression of DMT-1 and the ES showed high mRNA expression of transferrin and ferritin. The changes in the sorghum physicochemical properties from extrusion process reduced the iron and phytate content, and increased the gene expression of proteins involved in iron metabolism, improving iron bioavailability. The combination of sweet potato and sorghum flour (dry or extruded) improved the iron capture and total antioxidant capacity, probably due to the presence of β-carotene and antioxidant compounds.