外来种互花米草对江苏省潮间带生物地球化学过程的影响研究

Spartina alterniflora Loisel, a species vegetating in intertidal flats along the eastern coast of the United States, was introduced in China almost 30 years ago and has become an urgent topic due to its invasiveness in the coastal zone of China. The impacts of this alien species S. alterniflora on intertidal ecosystem processes in the Jiangsu coastland were investigated by comparing the sediment nutrient availability and trace element concentration characteristics in a mud flat and those of a four-year old Spartina salt marsh that had earlier been a mudflat. At each study site, fifteen plots were sampled in different seasons to determine the sediment characteristics along the tidal flats. The results suggested that Spartina salt marsh sediments had significantly higher total N, available P, and water content, but lower pH and bulk density than mudflat sediments. Sediment salinity, water content, total N, organic C, and available P decreased along a seaward gradient in the Spartina salt marsh and increased with vegetation biomass. Furthermore, the concentrations of trace elements and some metal elements in the sediment were higher under Spartina although these increases were not significant. Also, in the Spartina marsh, some heavy metals were concentrated in the surface layer of the sediment. The Spartina salt marsh in this study was only four years old; therefore, it is suggested that further study of this allen species on a longer time frame in the Jiangsu coastland should be carried out.     

氟虫腈在模拟稻田生态系中降解途径的研究

通过模拟试验的方法, 研究氟虫腈(fip ronil) 在稻田生态系中的降解与代谢途径, 结果表明: 在稻田水体中氟虫腈主要通过光解和水解作用降解为MB46513 和RPA 200766; 在土壤中以氧化和水解产物MB46136 和MB45950 为主; 在水稻植株中转化为氧化产物MB46136 和还原产物MB45950。     

甘露寡糖对犊牛的增重及血液免疫球蛋白的影响

甘露寡糖（Mannan Oligosaccharides, MOS）是低聚糖的一种,低聚糖是由2～10个单糖通过糖苷键连接形成的直链或支链的一类糖,化学性质稳定,不被动物消化也不能被有害菌利用,只能被消化道有益菌群如双歧杆菌和乳酸菌利用,通过优化肠道微生物生态系对宿主起有益的保健功能.改善肠道微生物组成、形成以双歧杆菌和乳酸杆菌为优势菌的肠道菌丛,抑制病原菌.MOS对病原菌有识别、粘附和排除作用,同时有利于排除内毒素保持动物健康.增强动物非特异性免疫,提高动物抵抗力.有研究结果表明MOS可提高动物细胞免疫和体液免疫水平.为了探讨MOS在犊牛生产中的使用效果及其作用机理,我们做了不同浓度MOS饲喂犊牛试验.