保护草原 增强草原碳汇功能

在全球气候变暖对人类生存和发展产生严峻挑战的背景下,全球陆地生态系统碳循环成了世界各国科学家研究的热点。草原是我国最大的陆地生态系统,具有丰富的碳储量,草原生态系统碳收支对我国乃至世界陆地生态系统的碳平衡都具有非常重要的影响。为此,对国内外草地生态系统碳储量估算研究进展、我国草原的退化问题及草原生态系统固碳技术措施与潜力进行了简要概述,提出了加强草原保护、增强草原生态系统固碳能力的对策与建议。     

奶牛主要植物性蛋白质饲料蛋白质和纤维物质瘤胃降解率的研究

选用3头安装永久性瘤胃瘘管的健康荷斯坦产奶牛为试验动物,选取8种北方地区奶牛常用蛋白质饲料原料为试验样品,每个样品设3个重复,用尼龙袋法分别测定各个样品的粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)在瘤胃内的动态降解率和有效降解率。结果表明:(1)所选8种蛋白质饲料原料中葵花粕的粗蛋白质(CP)有效降解率均高于其他粗饲料,达到61.17%以上,酒精粕的粗蛋白质(CP)有效降解率最低,仅为19.03%。(2)在饲喂基础上,玉米蛋白粉所含的瘤胃降解蛋白质(RDP)的比例最高,达到30.99%以上,而酒精粕所含的比例最低,仅为5.52%。(3)豆粕所含的中性洗涤纤维(NDF)的有效降解率最高,达到50.74%以上,而菜籽粕的最低,仅为11.06%。(4)玉米蛋白粉所含的酸性洗涤纤维(ADF)的有效降解率最高,达到59.23%以上,而酒精粕的最低,仅为11.27%。     

黄曲霉毒素危害、检测方法及生物降解研究进展

黄曲霉毒素(AF)是由某些真菌产毒菌株产生的次生代谢产物,具有极强的毒性.论文介绍了黄曲霉毒素对畜禽的危害以及薄层色谱(TLC)检测法、高效液相色谱(HPLC)检测法、酶联免疫(ELISA)检测法和放射免疫(RIA)检测法等检测方法,并对黄曲霉毒素生物降解的研究概况做一综述.     

泵站正向进水前池底坎整流机理数值模拟

为研究正向进水前池存在的不良流态,基于N-S方程和Realizable k-ε紊流模型,采用SIMPLE算法,数值模拟了正向进水前池中无任何措施和增设底坎整流措施的流态.CFD计算结果表明：原方案的前池两侧出现了大面积的回流区,泵站两侧机组进水条件差,水流偏斜较为明显;加底坎,且当底坎离进水池较远时,整流效果并不明显,前池内仍有大面积的回流产生,偏流依然严重;当底坎离进水池较近时,坎后旋涡直接影响到进水池的流态;通过CFD优化,底坎设在离进水池入口（7~10）D处,能明显改善前池的流态,水流能较均匀地流入各台机组;随着底坎坎高的增大,底层回流区会逐渐变小,较大回流区发生的位置也由坎后变为坎前,坎高的取值约为0.3H＇时,前池内流态较好;底坎的顶宽尺寸对前池流态的影响较小.CFD计算结果与试验结果基本吻合,研究成果对正向扩散前池流态改善有借鉴价值和实际意义.     

春甘蓝田小菜蛾种群动态研究

在田间系统调查的基础上,采用模糊聚类分析和时间动态空间生态位宽度与种群密度关系分析方法,研究了合肥地区春甘蓝田小菜蛾的种群动态,旨在为小菜蛾的科学治理提供依据。研究结果表明,春甘蓝田小菜蛾种群动态可分为3 个发展阶段——点片发生阶段（低密度、高聚块）、扩张发生阶段（中密度、低聚块）和猖獗发生阶段（高密度、低聚块）。小菜蛾对春甘蓝的为害情况比较复杂,种群密度较低时主要为害甘蓝心叶;随着甘蓝的生长和小菜蛾种群密度的上升逐渐向内层叶和外层叶扩展,最终导致甘蓝全株受害。小菜蛾种群处于点片发生阶段时是春甘蓝田小菜蛾防治的关键时期。     

土壤侵蚀退化研究

土壤退化是全球性的重大环境问题之一,直接威胁人类的生存。在引起土壤退化的诸因素中,土壤侵蚀是最普遍和最重要的因素。在前人土壤侵蚀退化研究成果的基础上简单回顾了其发展现状,重点综述了土壤侵蚀退化机理,并针对性地提出了土壤侵蚀退化防治措施。     

惠东拟囊腔吸虫种群动态研究

鲻体内的惠东拟囊腔吸虫（Ｓａｃｃｏｃｏｅｄｉｏｉｄｅｓ ｈｕｉｄｏｎｇｅｎｓｉｓ Ｌｕｅ,１９９３）随着宿主体长的生长,其感染强度,平均密度有逐渐增加的趋势,而感染率则呈不规划的波动;其感染率、感染强度和平均密度在不同月份亦呈不稳定变化;吸虫在宿主体内的频率分布表明,大量的吸虫寄生于少数宿主中,而多数宿主感染少量的吸虫;吸虫在不同体长组的分布类型为聚集分布,且聚集强度随种群密度的增加而增大。     

Characterization of Burkholderia sp. XTB‐5 for Phenol Degradation and Plant Growth Promotion and Its Application in Bioremediation of Contaminated Soil

A key issue when researching land degradation is the pollution of soils. For bioremediation of contaminated soil, Burkholderia sp. XTB‐5 cells were obtained from soil and grown on mineral salt medium with initial phenol concentrations of 650 mg L⁻¹ and 850 mg L⁻¹, which were found to degrade more than 98% of phenol content in less than 4 days. About 90% of phenol content (with initial concentration of 250 mg kg⁻¹ soil) was removed from soil inoculated with XTB‐5 cells in 6 days. More than 90% of phenol content was removed within 20 days after co‐introduction of XTB‐5 cells and plants to sterilized soil in a greenhouse or to natural soil in field trials. But under the same conditions, individual introduction of plants to sterilized soil in the greenhouse reduced phenol content by about 50% and introduction to natural soil in field trials reduced phenol content by about 38%, suggesting that phytoremediation of phenol is often inefficient and microorganisms can efficiently degrade this pollutant. In addition, strain XTB‐5 was found to solubilize phosphate and produce 1‐Aminocyclopropane‐1‐Carboxylate (ACC) deaminase and siderophore. Strain XTB‐5 promoted plant growth in both phenol‐absent and phenol‐spiked soil under greenhouse and field conditions. Considering that ACC deaminase is beneficial to plant growth under adverse environmental conditions, plant growth promotion by XTB‐5 in phenol‐contaminated soil is not only due to XTB‐5 cell‐degradation of phenol and reduced phytotoxicity but also to production of ACC deaminase. Hence, Burkholderia sp. XTB‐5 presents an attractive microorganism for phytoremediation of contaminated soil and agronomic application. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

异菌脲在设施草莓上的残留研究

为提供异菌脲在草莓上登记的残留检测方法、降解规律的相关资料,并为制定这种农药在草莓上合理使用的相关标准提供依据,采用建立的固相萃取—毛细管气相色谱(SPE—CGC)分析方法,研究了50%异菌脲可湿性粉剂在春季温棚和夏季大棚草莓果实上的残留动态和最终残留量。本测定方法平均添加回收率为88.15%～112.96%之间,标准偏差0.77%～4.54%。试验表明,异菌脲在不同设施条件下草莓上的残留消解方程均符合一级动力学方程。另外,环境条件是影响异菌脲残留的重要因素;异菌脲大部分残留于果实表面,果内残留远低于全果残留;加倍剂量比推荐剂量残留量高,降解慢。