Biocontrol of Cytospora canker of poplar in north‐east China with Trichoderma longibrachiatum

Trichoderma isolate T05, collected and isolated from a poplar (Populus simonii × Populus nigra) stand in the province of Heilongjiang, China, was tested for its efficacy in controlling Cytospora chrysosperma in vitro and Cytospora canker of poplar in the field. Trichoderma isolate T05 was identified as Trichoderma longibrachiatum in sect. Longibrachiatum based on both morphological characteristics and phylogenetic analysis of the nuclear ribosomal internal transcribed spacer (ITS1 and ITS2) oligonucleotide sequences and the short intron of tef1. During dual culturing, the inhibitory effect of T. longibrachiatum T05 on C. chrysosperma increased over time, and inhibition up to 81% was observed 120 h after inoculation. Hyphae of T. longibrachiatum T05 grew alongside, coiled and sporulated around the pathogen hyphae, which were generally observed to be wrinkled, collapsed, disrupted and degraded. Culture filtrates of T. longibrachiatum T05 that were sterilized by either bacterial filtration or autoclaving suppressed the growth of the pathogen colony. Filtrate sterilized by filtration showed greater inhibitory activity than the autoclaved filtrate, which still had some inhibitory activity, demonstrating that some inhibitory substances were heat unstable and some heat stable. Cytospora chrysosperma C01 colony growth was also reduced by volatile antibiotics produced by T. longibrachiatum T05, with inhibition of 54% observed after 96 h. In a field trial, Cytospora canker on poplar trunks was controlled with efficacy similar to that of routine chemical control by applying a T. longibrachiatum preparation.     

森林土壤渗透系数的数学模型

通过森林土壤渗透系数试验,应用数量化理论(Ⅰ)建立了森林土壤渗透系数的数学模型。影响森林土壤渗透系数的第一位因子是土壤质地与容重的交互作用,其次为土壤质地、容重、含根量、容重与含根量的交互作用。数量化理论(Ⅰ)可用于大面积森林土壤渗透系数的估算,其精度较高。     

悬挂农具对电液悬挂系统拖拉机振动的影响

悬挂农具设备的拖拉机在行驶过程中的振动会加剧,有时甚至产生很大的俯仰运动。为了研究悬挂农具的存在对拖拉机振动特性的影响,该文在对拖拉机进行运动学和动力学分析的同时,首次详细分析了悬挂机构的运动及受力情况,从而建立了带有悬挂农具的大功率拖拉机整机振动数学模型;用Matlab仿真了拖拉机受到条形水泥障碍激励时的振动情况。研究表明:农具的存在使拖拉机前轮动载系数由O.26增大到0.55;空载拖拉机垂直振动频率为3 Hz,带农具的拖拉机垂直振动频率为2.5 Hz;农具的存在使得拖拉机的俯仰振动显著增加,频率为4.8 Hz;由于悬挂系统的运动与拖拉机机体振动的非线性耦合,一定条件下会表现出频率为10~15 Hz的第3振型的振动;农具的振动使得电液悬挂系统下拉杆铰接点处的力发生相应变化,其垂直分量的大小与农具质心垂直加速度之间存在较好的线性关系。仿真结果与试验结果相吻合,验证了所建数学模型的正确性。所得到的上述结论为拖拉机主动减振控制提供了理论依据。     

大同盆地盐碱地甜菜高产配套技术研究

本文针对大同盆地盐碱地甜菜产量低、经济效益差的现状，从协调水、温、盐、肥的角度出发，系统分析和研究了大同盆地盐碱地的水盐运动特点和沟种集中施肥、提早覆膜、纸筒育苗移栽的抗盐保苗技术及在覆膜和露地种植下的科学用肥和合理密植等栽培管理措施，提出了盐碱地甜菜高产配套技术。据１９９０年生产示范；该项配套技术在各示范点覆膜和露地情况下增产均在２７．８％以上，高的可达８７．１％，具有明显经济效益，可在大同盆地     

Policosanol has no antioxidant activity in human low-density lipoprotein but increases excretion of bile acids in hamsters

Policosanol is a group of long chain primary alcohols and has been shown to reduce blood cholesterol levels and to inhibit the oxidation of low-density lipoprotein (LDL). The present study examined (i) the effect of policosanol supplementation in the diet on the fecal excretion of neutral and acidic sterols in hamsters and (ii) the antioxidant activity of policosanol in human LDL. Golden Syrian hamsters were divided into four groups (n = 12/each) fed one of the four diets containing 0 (control), 0.38, 0.75, and 1.50 g kg(-1) policosanol for 6 weeks. It was found that hamsters given 0.38-1.5 g kg(-1) diets had a serum total cholesterol level lowered by 15-25% and had a high-density lipoprotein cholesterol elevated by 7-16.8%. It was found that policosanol increased the excretion of acidic sterols by 25-73%. Contrary to that in previous reports, policosanol had no apparent anti-LDL oxidation activity when 1-tetracosanol, 1-hexacosanol, and 1-octacosanol were incubated in human LDL. Policosanol also possessed no scavenging activity on the free radical2,2-diphenyl-1-picrylhydrazyl. These data provide evidence that in addition to the effect of HMG-CoA reductase, the cholesterol-lowering activity of policosanol is partially mediated by its inhibition on the absorption of bile acids, but these data disprove the claim that policosanol is an antioxidant.     

水稻节水高产灌溉模式及土壤水分能量调控标准研究

根据土壤—植物—大气连续系统原理，1989～1998年在沈阳农业大学灌溉试验场通过盆载、蒸渗仪、小区及大田进行试验，分析了水稻的需要水规律及稻田土壤水分能量的变化特点，论述了土壤水分状况与水稻腾发强度之间的关系、不同灌模式对水稻腾发量的调控作用以及水分胁迫对水稻产量的影响，提出了水稻节水高产灌溉模式和土壤水分能量调控标准。     

Cross-linking and rheological changes of whey proteins treated with microbial transglutaminase

Modification of the functionality of whey proteins using microbial transglutaminase (TGase) has been the subject of recent studies. However, changes in rheological properties of whey proteins as affected by extensive cross-linking with TGase are not well studied. The factors affecting cross-linking of whey protein isolate (WPI) using both soluble and immobilized TGase were examined, and the rheological properties of the modified proteins were characterized. The enzyme was immobilized on aminopropyl glass beads (CPG-3000) by selective adsorption of the biotinylated enzyme on avidin that had been previously immobilized. WPI (4 and 8% w/w) in deionized water, pH 7.5, containing 10 mM dithiothreitol was cross-linked using enzyme/substrate ratios of 0.12-10 units of activity/g WPI. The reaction was carried out in a jacketed bioreactor for 8 h at 40 degrees C with continuous circulation. The gel point temperature of WPI solutions treated with 0.12 unit of immobilized TGase/g was slightly decreased, but the gel strength was unaffected. However, increasing the enzyme/substrate ratio resulted in extensive cross-linking of WPI that was manifested by increases in apparent viscosity and changes in the gelation properties. For example, using 10 units of soluble TGase/g resulted in extensive cross-linking of alpha-lactalbumin and beta-lactoglobulin in WPI, as evidenced by SDS-PAGE and Western blotting results. Interestingly, the gelling point of WPI solutions increased from 68 to 94 degrees C after a 4-h reaction, and the gel strength was drastically decreased (lower storage modulus, G'). Thus, extensive intra- and interchain cross-linking probably caused formation of polymers that were too large for effective network development. These results suggest that a process could be developed to produce heat-stable whey proteins for various food applications.     

武汉与宜昌太阳总辐射与气象要素的关系对比研究

利用武汉市及宜昌市2007-2008年逐时太阳总辐照量和气象要素(气温、相对湿度、云量等)实况观测资料,对比分析两地逐时太阳总辐照量与气象要素的关系。研究结果表明,太阳总辐照量具有明显的季节差异,武汉总辐照量值较宜昌地区显著偏大;两地太阳总辐照量与各气象要素相关性大体类似,不同的是宜昌气温、相对湿度及低云量与总辐照量的相关性比武汉差,而总云量与总辐照量的相关性比武汉好;详细统计了(低、总)云量与总辐照量的相关关系,对各种天气类型(阴、晴等)进行分析后发现(低、总)云量对总辐照量影响很大,云量与太阳总辐照量存在比较明显的负相关;最高(低)气温与总辐照量最大(小)值存在时间差;两地夏冬两季相对湿度与总辐照量呈现出较为明显的负相关。     

臭氧对多种偶氮染料的处理效果的研究

[目的]研究臭氧对4种偶氮染料的处理效果.[方法]利用臭氧在相同条件下处理4种偶氮染料(酸性黑ATT、酸性大红3R、酸性品红、碱性品绿)废水,研究臭氧对这4种染料的降解效果.[结果]臭氧对4种偶氮染料的脱色效果分别是酸性大红3R＞酸性品红＞酸性黑ATT＞碱性品绿.在既定条件下,臭氧对酸性大红3R的脱色效果好于酸性品红,臭氧对酸性大红3R和酸性品红溶液的处理时间短且都能达到很好的COD去除率.但是,臭氧对酸性黑ATT和碱性品绿尤其是碱性品绿的处理不是十分的理想,所需时间较长.[结论]利用臭氧处理不同的染料需要根据不同的染料性质去改变其相应的条件.     

椰心叶甲在中国的适生性分布

根据对入侵害虫椰心叶甲[Brontispalongissima(Gestro)]生物学、生态学实验研究及信息分析,利用地理信息系统ArcviewGIS3.3分析预测了其在中国大陆的可能适生范围。结果表明,椰心叶甲在中国的高度适生范围大体在16.53￣25.73°N,97.85￣118.91°E,涉及华南、西南、华东5个省(自治区)的58个点;潜在适生区分布范围大体在22.98￣33.87°N,88.88￣122.81°E,涉及华南、西南、华东、华中、西北等地区19个省(自治区、直辖市)的239个点。