几种草坪草脯氨酸含量变化规律的研究

以自然条件下生长的3种常见的冷季型草坪草品种早熟禾属优异(Poa pratensis L.cv.Merit)、抢手股(Poa pratensis L.cv.Blue chip)和紫羊茅属的紫羊茅(Festuca rubra L.cv.Cindy)和暖季型草坪草地毯草(Axorupus cornpressus(Sw.)Beauv.)和假俭草(Eremochloa ophiuroides)为材料,跟踪调查和测定了几种草坪草的脯氨酸含量变化规律,为进一步揭示脯氨酸在草坪草抗旱、抗寒和耐热中的作用奠定基础。     

高温胁迫对松毛虫赤眼蜂生长发育的影响

以松毛虫赤眼蜂为试验材料,研究了高温胁迫对松毛虫赤眼蜂生长发育的影响。结果表明:处于蛹后期虫态的柞蚕赤眼蜂对环境高温较为敏感,尤其在环境温度超过40℃以后,短期即可对其羽化出蜂造成较大影响;蛹后期虫态赤眼蜂较蛹中期更易受到高温的负面影响。     

Experiences and Research Perspectives on Sustainable Development of Rice-Wheat Cropping Systems in the Chengdu Plain,China

The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included： 1） creating a favorable environment and viable rotations; 2） balanced fertilization for maintenance of sustainable soil productivity; 3） improvement of crop management for higher efficiency; and 4） use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as： 1） the constant topic： a highly productive and efficient rice-wheat cropping system for sustainable growth; 2） the future trend： simplified cultivation techniques for the rice-wheat cropping system; 3） the foundation： basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.     

开垦对三江平原别拉洪河流域土壤Fe活性的影响

为探讨农业开垦对土壤Fe活性的影响,采集土样对三江平原别拉洪河流域不同土地利用类型(岸边沼泽、农田附近沼泽、农田)泥炭层、表土层和潜育层中Fe2+、络合Fe及土壤相关理化指标进行分析。结果表明,土壤开垦后,与岸边天然沼泽相比,农田附近沼泽及农田土壤Fe2+、络合Fe含量整体上呈降低趋势,显示开垦促进了土壤有机碳损失,降低了土壤Fe活性。不同土地利用类型土壤各层中络合Fe与土壤TOC相关性显著,表明TOC是影响土壤Fe活化的重要因子。研究结果有助于深入了解土地利用状况变化对土壤Fe活性的影响,进而为耕地的合理开垦提供一定的理论依据。     

德氏乳杆菌亚油酸异构酶酶学性质

对从德氏乳杆菌保加利亚亚种中提取出来的亚油酸异构酶进行酶学性质研究。结果表明,该酶最适pH为6.0;最适温度为40℃,此时酶活力最高;金属离子Mg2+、Na+、Zn2+可使酶活力有所提高,Fe2+和Mn2+离子对酶促反应有明显的抑制作用;以Lineweaver-Burk双倒数作图法求得亚油酸异构酶的Km为0.0285 mol.L-1,Vm为2.31 mg.mL-1.h-1。     

北京市引进的4种彩叶灌木的生态效益研究

以北京市引进的4种彩叶灌木(金叶莸、金叶女贞、紫叶矮樱、紫叶小檗)为研究对象,通过测定其光合速率和蒸腾强度,估算其固碳释氧量和降温增湿量,测定滞尘量,并比较了这4种彩叶植物的生态效益。结果表明:金叶莸的生态效益最高,紫叶小檗和金叶女贞的生态效益相当,紫叶矮樱维持碳氧平衡和降温增湿效应较小,但滞尘能力较强。在园林绿化实践中,可以优先选择金叶莸作为黄色系植物,在空气粉尘污染较严重的地方则可以考虑金叶莸和紫叶矮樱。     

滴灌条件下不同产量棉花氮磷钾积累的模拟分析

[目的]研究滴灌条件下,不同产量棉花科学施肥氮、磷、钾配比、施用时间及施用量。[方法]利用Logistic方程,分析不同产量棉株各个生育期的氮、磷、钾的积累量。[结果]高产和中产棉株对氮磷钾最大积累量和积累最高速率远大于低产棉株。滴灌棉株出苗后40～95d左右是氮积累的旺盛期,出苗后51～110d左右是磷积累的旺盛期,出苗后47～90d左右是钾积累的旺盛期。[结论]保证棉株苗蕾至花铃前期吸收足量的氮,满足棉株花铃期到吐絮期对磷的高强度需求,并保持棉株生育后期对钾仍有旺盛的吸收能力,是形成棉花高产的重要因素。     

稻秆醋液成分分析及抑菌·杀菌性能研究

[目的]寻求稻秆的利用途径。[方法]采用气相色谱-质谱联用仪分析了稻秆粗醋液和精制醋液的主要化学成分,并对2种醋液的抑菌、杀菌性能进行了研究。[结果]2种醋液均含有45种有机组分的混合物,主要含有有机酸类、酮类、醇类、酚类、酯类、醛类及其他组分。以热带假丝酵母菌、黑曲霉菌、大肠杆菌和金黄色葡萄球菌为指示菌,1∶9（V醋液∶V水,下同）、1∶6、1∶9、1∶6的粗醋液与1∶7、1∶3、1∶4、1∶3的精制醋液分别对4种指示菌达90%以上的抑菌作用;1∶9、1∶6、1∶9、1∶6的粗醋液与1∶7、1∶3、1∶5、1∶3的精制醋液分别对4种指示菌达90%以上的杀菌作用。[结论]稻秆醋液具有较强的抑菌和杀菌作用。     

莫尔道嘎林业局森林资源变化分析

文章根据莫尔道嘎林业局2009年森林资源统计数据,简单阐述林业局森林资源状况和森林资源变化情况     

Evaluation of multicomponent recombinant vaccines against Actinobacillus pleuropneumoniae in mice

Background

Porcine contagious pleuropneumonia (PCP) is a highly contagious disease that is caused by Actinobacillus pleuropneumoniae (APP) and characterized by severe fibrinous necrotizing hemorrhagic pleuropneumonia, which is a severe threat to the swine industry. In addition to APP RTX-toxins I (ApxI), APP RTX-toxin II (ApxII), APP RTX-toxin III (ApxIII) and Outer membrane protein (OMP), there may be other useful antigens that can contribute to protection. In the development of an efficacious vaccine against APP, the immunogenicities of multicomponent recombinant subunit vaccines were evaluated.

Methods

Six major virulent factor genes of APP, i.e., apxI, apxII, apxIII, APP RTX-toxins IV (apxIV), omp and type 4 fimbrial structural (apfa) were expressed. BALB/c mice were immunized with recombinant ApxI ( rApxI), recombinant ApxII (rApxII), recombinant ApxIII (rApxIII) and recombinant OMP (rOMP) (Group I); rApxI, rApxII, rApxIII, recombinant ApxIV (rApxIV), recombinant Apfa (rApfa) and rOMP (Group II); APP serotype 1 (APP1) inactivated vaccine (Group III); or phosphate-buffered saline (PBS) (Control group), respectively. After the first immunization, mice were subjected to two booster immunizations at 2-week intervals, followed by challenge with APP1 Shope 4074 and APP2 S1536.

Results

The efficacy of the multicomponent recombinant subunit vaccines was evaluated on the basis of antibody titers, survival rates, lung lesions and indirect immunofluorescence (IIF) detection of APP. The antibody level of Group I was significantly higher than those of the other three groups (P < 0.05). The survival rate of Group I was higher than that of Groups II and III (P < 0.05) and the control (P < 0.01). Compared with the other three groups, the lungs of Group I did not exhibit obvious hemorrhage or necrosis, and only showed weak and scattered fluorescent dots by IIF detection.

Conclusion

The result indicates that the multicomponent recombinant subunit vaccine composed of rApxI, rApxII, rApxIII and rOMP can provide effective cross-protection against homologous and heterologous APP challenge.