上海市小白菜高效安全生产现状与建议

上海市设施土壤栽培小白菜生产管理现状调查表明,本地区小白菜生产存在种子成本高、水肥管理粗放、生产效率低下等问题,建议继续加强小白菜高效安全生产模式建设,推广种子加工处理、水肥一体化、病虫害绿色防控关键生产环节机械化等技术的应用。     

野生猕猴桃实生后代株系对溃疡病的抗性及果实品质

为猕猴桃种质资源的开发和利用提供参考，以野生黄肉猕猴桃实生苗为试材，采用大田病圃法对198份黄肉野生猕猴桃实生株系连续4年进行田间溃疡病抗性监测，以明确不同野生猕猴桃实生后代株系对溃疡病的抗性差异，并对野生猕猴桃实生株系中60株雌株果实风味进行初步品评。结果表明：猕猴桃实生苗后代对溃疡病的抗性不同。其中，高抗、中抗、耐病、感病和高感株系所占总体比例分别为11.16%、24.75%、29.80%、28.28%和5.56%，初步筛选出12株抗病性较强的雌株株系和10株抗病性较强的雄株株系。结合猕猴桃单果重、果实品质及对溃疡病抗性等方面，筛选出4株优良抗性雌株实生苗为株系13-3-2、13-6-11、13-11-1和13-11-21，其可溶性固形物含量均在14.5%以上，风味好，Vc含量均显著高于母本，分别较母本高18.14%、105.3%、65.21%和11.34%。     

高含固率木质纤维素厌氧发酵物总DNA的4种提取方法比较

不同的样本特性和提取方法对获得微生物总DNA的质量有重要影响。文章基于高含固率木质纤维素厌氧发酵物腐殖酸、酚类物质含量高、质地均一性差、微生物浓度低的特点,研究了4种方法提取不同高含固率粪秸厌氧发酵物中微生物总DNA的效果。结果表明,常规的十二烷基磺酸钠法(sodium dodecyl sulfate,SDS)、十二烷基磺酸钠和溴化十六烷基三甲铵结合法(sodium dodecyl sulfate and cetyltrimethyl ammonium bromide,SDS-CTAB)和商业的粪便试剂盒法提取的DNA质量均较差,SDS法和试剂盒法未能获得聚合酶链式反应(polymerase chain reaction,PCR)扩增目的条带,SDS-CTAB法得到的条带较模糊;改进SDS-CTAB法获得的DNA杂质少、纯度高,具有较好的稳定性,A260/A280和A260/A230值分别为1.74~1.86和1.65~1.86,每克样品的DNA浓度在50 ng·μL^-1以上,电泳条带单一齐整、清晰明亮,PCR扩增的目的条带清晰度高,适宜后续分子生物学技术的分析。林格氏液洗脱、聚乙烯吡咯烷酮-40(Polyvinyl Pyrrolidone-40,PVP-40)洗涤液除杂以及裂解液和多种酶联合破壁是改进SDS-CTAB法获得该类专一性样本高质量微生物总DNA的关键步骤。     

饲料蛋白水平对芙蓉鲤鲫幼鱼增重和消化酶活性的影响

以进口鱼粉和豆粕为饲料蛋白源,研究了6种蛋白水平(分别为27%、30%、33%、36%、39%和42%)的等能饲料对芙蓉鲤鲫幼鱼增重和肠道、肝脏消化酶活性的影响。结果表明,饲料蛋白水平的增加,显著地提高了鱼体增重率、特定生长率、饲料效率、肥满度(P<0.05),并降低了饵料系数和脏体比,还显著地提高了肠道组织蛋白酶、食糜蛋白酶和GOT及GPT活性(P<0.05)。随着饲料中蛋白水平的上升,肝脏蛋白酶和食糜、肠道组织、肝脏淀粉酶活性无显著性差异(P>0.05)。     

规模化蛋鸡场病原菌溯源与生物安全防控研究

细菌病严重威胁蛋鸡健康,以抗生素为主导的细菌病传统防控方式会导致病原菌耐药性严重、鸡蛋药物残留,影响蛋品安全。要保证蛋鸡产蛋期不用抗菌药物而又能生产出"无菌、无抗"的鸡蛋,是国内外技术难题。本团队以规模化蛋鸡场全封闭鸡舍为研究对象,基于PFGE、MLST、全基因组测序等技术,探明了蛋鸡病原菌的种类及基因组特征;对病原菌的耐药性研究表明,蛋鸡病原菌多重耐药严重,依靠药物防控的方式亟待转变;对规模化蛋鸡场细菌溯源研究结果表明,鸡舍生物媒介(鼠、苍蝇等)和非生物媒介(空气、饮水、饲料、鸡粪等)是蛋鸡病原菌的重要传染来源和传播途径;对规模化蛋鸡场生物安全量化评价结果表明,外部和内部生物安全权重高达92.2%。根据溯源和生物安全权重分析结果,提出了在规模化全封闭蛋鸡舍将蛋鸡细菌病从药物防控转变为生物安全防控的新策略;创新了规模化蛋鸡场细菌病防控的系统技术,实现蛋鸡规模养殖整个产蛋期不用抗生素,为生产"无菌、无抗"安全鸡蛋提供技术支撑。     

Influences of sand cover on erosion processes of loess slopes based on rainfall simulation experiments

Aeolian-fluvial interplay erosion regions are subject to intense soil erosion and are of particular concern in loess areas of northwestern China.Understanding the composition,distribution,and transport processes of eroded sediments in these regions is of considerable scientific significance for controlling soil erosion.In this study,based on laboratory rainfall simulation experiments,we analyzed rainfall-induced erosion processes on sand-covered loess slopes(SS)with different sand cover patterns(including length and thickness)and uncovered loess slopes(LS)to investigate the influences of sand cover on erosion processes of loess slopes in case regions of aeolian-fluvial erosion.The grain-size curves of eroded sediments were fitted using the Weibull function.Compositions of eroded sediments under different sand cover patterns and rainfall intensities were analyzed to explore sediment transport modes of SS.The influences of sand cover amount and pattern on erosion processes of loess slopes were also discussed.The results show that sand cover on loess slopes influences the proportion of loess erosion and that the compositions of eroded sediments vary between SS and LS.Sand cover on loess slopes transforms silt erosion into sand erosion by reducing splash erosion and changing the rainfall-induced erosion processes.The percentage of eroded sand from SS in the early stage of runoff and sediment generation is always higher than that in the late stage.Sand cover on loess slopes aggravates loess erosion,not only by adding sand as additional eroded sediments but also by increasing the amount of eroded loess,compared with the loess slopes without sand cover.The influence of sand cover pattern on runoff yield and the amount of eroded sediments is larger than that of sand cover amount.Furthermore,given the same sand cover pattern,a thicker sand cover could increase sand erosion while a thinner sand cover could aggravate loess erosion.This difference explains the existence of intense erosion on slopes that are thinly covered with sand in regions where aeolian erosion and fluvial erosion interact.     

硒对母猪氧化应激及其后代抗氧化能力的营养调控研究

硒作为的重要微量元素之一,可以通过胎盘和乳组织进行转移。仔猪可以从乳汁中获取硒源,提高硒含量,进而提高仔猪的初生重。同时,硒也能够调节母猪妊娠期间代谢速度,控制妊娠期自由基产生,进而提高胎盘输送营养功能。文章从母猪氧化应激体系角度来解析硒对母猪妊娠期氧化应激的调控机制、硒对哺乳母猪生产性能的调控作用。     

Effects of the severity and timing of basal leaf removal on the amino acids profiles of Sauvignon Blanc grapes and wines

The effects of the severity and timing of leaf removal(LR) on the amino acids of Sauvignon Blanc grapes and wines were studied during the 2017 growing season. High-performance liquid chromatography(HPLC) was used to analyze the amino acids profiles of grape berries and wines. The basal leaves were removed at three time points(40, 56 and 72 days after flowering, named LR40, LR56 and LR72, respectively) at two severity levels(one at which the first, third, and fifth basal leaves of each shoot were removed(50% level); and another at which the first six basal leaves were removed(100% level)). The results showed that leaf removal had little impact on total soluble solids(°Brix), titratable acidity, pH or berry weight. The LR72-50% treated grapes had higher berry weight, titratable acidity and °Brix than those of the other treatments. The highest concentrations of total amino acids and of total amino acids except proline were detected in LR72-50% treated grapes(2 952.58 and 2 764.36 mg L~(-1), respectively); the lowest were detected in LR72-100% treated grapes(2 172.82 and 2 038.71 mg L~(-1), respectively). LR72-50% treatment significantly promoted the synthesis of aspartic acid, serine, arginine, alanine, aminobutyric acid and proline at both severity levels for grapes, the concentrations of all of these amino acids were increased relative to the control concentrations. The LR72-50%, LR40-100% and LR72-100% treated wines had higher total amino acids concentrations and higher concentrations of some individual amino acids, such as arginine, alanine and serine, than did the control wines. Of all the amino acids studied, glycine, tyrosine, cysteine, methionine and lysine were not significantly influenced by the timing or severity basal defoliation in grapes and wines. The present study reveals the effects of the timing and severity of leaf removal on the amino acids profiles of grapes and wines.     

持续低温胁迫下大花蕙兰不同组织器官耐寒响应

采用自然降温处理,分别测定了大花蕙兰地上部分和地下部分中丙二醛(MDA)含量、膜透性(CMP)、可溶性蛋白质(SP)含量、可溶性糖(SS)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性和过氧化氢酶(CAT)活性等与耐寒性有关的生理指标,比较地上部分和地下部分耐寒差异性,研究低温胁迫对大花蕙兰组培苗生理特性的影响。结果表明:POD活性、可溶性蛋白质含量和可溶性糖含量在反映大花蕙兰组培苗耐寒性方面作用明显,可作为其耐寒性鉴定指标;地上部分和地下部分在耐寒性提高时表现出不一致性,后者比前者表现出更强的耐寒性能。