20.67%万兴EC对香蕉叶斑病的防治效果及持效期试验初报

用20.67%万兴乳油1000倍液防治香蕉叶斑病。结果表明:每隔10d施药1次,连续施药3次后,第7、15、25和35天的防效分别为76.21%、75.68%、69.99%和62.80%;每隔20d施药1次,连续施药3次后,第10天的防效为69.08%,对香蕉安全。     

施钼对夏大豆产量及品质的影响

采用田间小区试验,研究了施钼对夏大豆农艺性状,产量及品质的影响。结果表明,施钼明显促进了夏大豆株高和底荚高的增长,增加了夏大豆的百粒重,总荚数和单株籽粒重,提高了夏大豆产量,蛋白质含量增加,脂肪含量下降,但公顷脂肪产量增加。     

小陇山森林旅游发展现状分析与对策

指出了随着林业体制改革的不断深入,必将要求林业单位经营结构的转变。逐步由单一的木材经营模式向多元化经营模式发展,以森林为依托,市场为导向,适应我国林业向生态、经济和社会可持续发展的需求。基于此,分析了小陇山森林公园经营现状,探讨了在发展中存在问题与解决对策,以期为进一步切实推动林业第三产业可持续发展建设提供参考。     

Differential root responses in two cultivars of winter wheat (Triticum aestivum L.) to elevated ozone concentration under fully open‐air field conditions

The effect of elevated tropospheric ozone concentration [O₃] on root processes in wheat systems of different O₃ sensitivity is not well understood. Two wheat cultivars (cv. Y15 and YN19) with contrasting O₃ tolerance were grown in a fully open‐air O₃ enrichment platform for one season. We found that elevated O₃ (EO₃) (50% above the ambient O₃) significantly decreased the total biomass at all key growth stages and the yield of the O₃‐sensitive cultivar YN19 but did not affect those of the O₃‐tolerant cultivar Y15. EO₃ significantly decreased the root biomass of two wheat cultivars at the jointing and grain‐filling stages. EO₃ significantly decreased the root length, length density, surface area and volume of the two cultivars at the jointing stage but increased those of YN19 at the grain‐filling stage. EO₃ significantly increased the root activities (specific root respiration rates) of Y15 and YN19 at the jointing, heading and grain‐filling stages. EO₃ significantly decreased the contribution of fresh root respiration to soil respiration (CRS) of YN19 at the jointing stage but increased it at the heading stage; however, it did not change the CRS of Y15 at any growth stages. This study indicates that the effects of EO₃ on root morphology and activity varied among wheat cultivars, and suggest that we can breed O₃‐tolerant cultivars to maintain crop yield under higher [O₃] scenarios.     

Antihyperlipidemic and Antitumor Effects of Chickpea Albumin Hydrolysate

This study was undertaken to determine the effects of chickpea albumin hydrolysate (CAH) on antihyperlipidemic and antitumor functions. The antihyperlipidemic results showed that CAH exhibited a dose dependent ability to decrease the levels of serum total cholesterol, triglyceride, LDL cholesterol (LDL-C), while increasing HDL cholesterol (HDL-C). Additionally, the appearance of the hyperlipidemic livers was ameliorated significantly. The antitumor results showed that CAH administration significantly increased the tumor inhibition rate and decreased tumor volume. CAH was also able to increase the spleen index and promote spleen lymphocyte proliferation. In addition, CAH treatment led to a remarkable rise in the superoxide dismutase (SOD) activity, while dramatically decreasing malondialdehyde (MDA) in the liver. Most importantly, we found that the physical conditions, such as appetite, activity, and coat luster of the mice in the CAH test group were better than those in the tumor control (TC) and positive control (PC) groups. These results taken together indicate that CAH warrants being further investigated and developed as an adjunctive element for hepatic lipid control, as well as antitumor and hypolipidemic therapies.     

汽车磁流变半主动悬架系统设计与试验

为了提高汽车的平顺性和行驶稳定性,设计了一种安装双出杆式磁流变减振器的汽车半主动悬架系统。在分析传统的磁流变减振器力学模型的基础上,提出了一种改进的磁流变减振器多项式模型,建立了基于磁流变减振器的半主动悬架系统动力学模型;设计了磁流变减振器物理样机,进行了磁流变减振器的力学特性试验,获得该磁流变减振器的示功特性和速度特性曲线,并利用试验结果进行了模型参数识别与模型验证。考虑时滞对悬架系统的影响,计算了该磁流变半主动悬架的临界时滞,采用Smith预估时滞补偿控制策略,设计了磁流变半主动悬架模糊时滞控制器;利用Matlab软件进行了磁流变半主动悬架时滞补偿控制仿真对比分析;研制了汽车半主动悬架测试系统,开展了磁流变半主动悬架控制台架试验。仿真与试验结果表明,所研制的磁流变减振器耗能效果良好,控制灵敏;试验建模所获得的改进型磁流变减振器多项式力学模型是正确的。与被动悬架相比,在正弦激励和随机路面谱输入下磁流变半主动悬架的簧载质量加速度下降30%左右,减振效果明显。     

IbeB is involved in the invasion and pathogenicity of avian pathogenic Escherichia coli

The ibeB gene in neonatal meningitis Escherichia coli (NMEC) contribute to the penetration of human brain microvascular endothelial cells (HBMECs). However, whether IbeB plays a role in avian pathogenic E. coli (APEC) infection remains unclear. Thus, this study was conducted to investigate the distribution of the ibeB gene in Chinese APEC strains and examine whether IbeB is involved in APEC pathogenicity. The ibeB gene was found in all 100 detected E. coli isolates with over 97% sequence homology. These results indicated that ibeB is a conserved E. coli gene irrelevant of pathotypes. To determine the role of ibeB in APEC pathogenicity, an ibeB mutant of strain DE205B was constructed and characterized. The inactivation of ibeB resulted in reduced invasion capacity towards DF-1 cells and defective virulence in animal models as compared to the wild-type strain. Animal infection experiments revealed that loss of ibeB decreased APEC colonization and invasion capacity in brains and lungs. These virulence-related phenotypes were partially recoverable by genetic complementation. Reduced expression levels of invasion- and adhesion-associated genes in ibeB mutant could be major reasons as evidenced by reduced ibeA and ompA expression. These results indicate that IbeB is involved in APEC invasion and pathogenicity.     

大气CO2浓度升高和氮肥水平对麦田土壤有机碳更新的影响

依托FACE（Free air carbon dioxide enrichment）技术平台,采用稳定¹³C同位索法,通过将C₃作物小麦种植于长期单作玉米的C₄土壤上,研究了大气CO₂浓度升高和不同氮肥水平对水稻-小麦轮作制中冬小麦生长季土壤有机碳更新的影响。结果表明,种植一季小麦后土壤有机碳的δ¹³C值显著降低,小麦生长改变了土壤有机碳的组成,大气CO₂浓度增加促进作物向土壤中输入更多的碳。大气CO₂浓度升高增加了麦田土壤有机碳的更新率,使土壤有机碳的更新率由3.61%(施氮量为150 kg hm^-2,LN)～4.59%(施氮量为250 kg hm^-2,HN)提高至6.72%（LN）～8.55%（HN）,分别增加72.7%和86.1%。结果表明,大气CO₂浓度升高和提高氮肥用量将加快农田土壤有机碳的更新。