施硅量对甜荞倒伏及产量的影响

【目的】通过研究硅肥对甜荞倒伏和产量相关性状的影响,筛选甜荞栽培最适施硅量,为其实现高产、稳产、抗倒伏提供参考。【方法】以宁荞1号（中抗倒伏）为试验材料,2015-2016年在西南大学歇马科研基地进行田间试验,试验设置基施0（CK）、100 kg·hm^-2（S1）、200 kg·hm^-2（S2）、300 kg·hm^-2（S3）和400 kg·hm^-2（S4）5种施硅量梯度（SiO₂≥25%）,研究各生育阶段不同器官硅含量及倒伏和产量相关指标。【结果】（1）根中硅含量高于茎,从盛花期到成熟期先增后减,在灌浆期达到最大值,并且随着施硅量的增加而增加;茎中硅含量从盛花期到成熟期逐渐增加,随着施硅量增加先增后减。（2）总根长、总根表面积、平均根直径和根尖数从盛花期到成熟期逐渐增加;根表面积随施硅量的增加而增加;平均根直径和根尖数随着施硅量增加先增加后减少,S2处理达到最大值。（3）茎秆基部第二节间长度、直径、鲜重和抗折力从盛花期到成熟期逐渐增加;茎秆基部第二节间长度、直径随施硅量的增加而增加;茎秆基部第二节间鲜重和抗折力随着施硅量的增加先增加后减少,均在S3处理达到最大值。（4）木质素含量从盛花期到成熟期逐渐增加,4CL、PAL和CAD活性从盛花期到成熟期先升后降,在灌浆期达到最大值;木质素含量,4CL、PAL和CAD活性随着施硅量的增加先升后降,在S3处理达到最大值。（5）硅肥降低甜荞倒伏级别,显著减小倒伏率;当施硅量在300-400 kg·hm^-2时,甜荞倒伏时期推迟到成熟期。（6）产量、单株粒重和千粒重随着硅肥施用量的增加先增后减;单株粒数随着硅肥施用量的增加而增加。【结论】本试验条件下,硅肥基施300 kg·hm^-2效果最佳,可在实际生产中推广应用。     

华南农业大学兽医学科的历史与未来

华南农业大学兽医学院具有悠久的历史。1952年全国高交院系调整时，由中山大学、岭南大学和广西大学的畜牧兽医系合并建成华南农学院畜牧兽医系，我国著名的兽医学家邝荣禄教授担任首任系主任。1984年华南农学院更名为华南农业大学，1987年畜牧、兽医分别独立成系，1993年兽医系更名为动物医学系，2001年改名为兽医学院。     

Simulation of groundwater table dynamics based on Feflow in the Minqin Basin,China

As groundwater table declination is an important factor resulting in degradation of eco-environment in the Minqin Basin,China,it is significant to investigate and understand the groundwater table dynamics in this area. According to the physical and geographical conditions of the Minqin Basin,a hydrogeological conceptual model and a mathematical model were established,and the mathematical model was figured out by using Finite Element subsurface Flow system(Feflow).Accurate hydrogeological parameters were acquired,and the spatio-temporal distribution dynamics of groundwater table for 1983–2001 were also simulated.The model performed well with a correlation coefficient of 0.977 and a mean error of 0.9768 m.The inflow and outflow of the groundwater system were predicted by time series analysis,and the groundwater table dynamics for 2011 were further acquired.Generally the groundwater table in the Minqin Basin would continue to decline.The groundwater table would decline during spring and summer irrigation,while it would rise during autumn-winter irrigation.The groundwater depression cones would expand with the increase of center depths.Therefore,regulatory measures should be taken to prevent the declination of groundwater table and improve the eco-environment of this area.     

土壤修复菌M-1固体发酵配方研究

固体发酵培养基配方筛选结果表明,腐殖酸(65%)+土(10%)+玉米粉(20%)+豆饼粉(5%)+生石灰(0.6%)较适合M-1菌株的生长繁殖,菌数达到14.9×108cfu/g,远远超出土壤肥料有效活菌数的行业标准。对该菌株培养条件进行正交试验,结果表明,生石灰量0.4%、含水量40 ml、发酵时间6 d为菌株的最佳发酵条件,有效活菌数达到136×108cfu/g,是初始有效活菌数的近10倍。     

日粮添加肉桂醛对奶牛公犊生长、健康及瘤胃发酵性能的影响

【目的】在犊牛开食料中添加肉桂醛,研究其对早期奶牛公犊生长性能、健康、瘤胃发酵及微生物区系的影响,为肉桂醛在早期犊牛的培育应用提供理论依据。【方法】试验选24头出生2周龄、体重相接近,健康状况良好的荷斯坦奶牛公犊,分为对照组和试验组,每组3个重复,每个重复4头,对照组饲喂基础开食料,试验组在开食料中添加0.3%含油率为15%的包被肉桂醛。哺乳期预饲期6 d,正饲期27 d,两组饲喂等量牛奶,开食料及燕麦草自由采食,断奶日通过胃管采集瘤胃液;断奶后全部动物按照相同饲养管理方式继续饲喂51 d,试验末通过胃管采集瘤胃液。试验期的两个阶段均测定奶牛公犊采食量,生长性能、体尺指标、粪便评分和瘤胃挥发性脂肪酸指标,并基于16SrDNA基因高通量测序法对奶牛公犊瘤胃细菌区系测定分析。【结果】1)在采食量和生长性能方面,犊牛哺乳阶段、断奶后以及试验全期,试验组的平均日增重、干物质采食量、料重比等指标与对照组差异不显著(P>0.05),试验组与对照组在体尺指标中各阶段差异不显著(P>0.05);2)在犊牛健康方面,试验组犊牛腹泻率均低于对照组,但与对照组腹泻率差异不显著(P>0.05);3)在瘤胃发酵指标方面,断奶日试验组各挥发性脂肪酸的含量均低于对照组,但差异不显著(P>0.05);试验末试验组乙酸、丙酸、丁酸、戊酸和总挥发性脂肪酸极显著高于对照组（P<0.01）;4) 试验末,肉桂醛显著提高了瘤胃香农多样性指数,降低了辛普森指数;在门水平上降低了Bacteroidetes菌群丰度,提高了Firmicutes和Actinobacteria丰度;在属水平上仅提高了Prevotella丰度。【结论】通过开食料对犊牛补饲0.3%含油率为15%的包被肉桂醛对哺乳期及断奶后的生长性能没有影响,但降低了腹泻率,显著提高了断奶犊牛瘤胃挥发性脂肪酸浓度并降低了乙酸/丙酸比例,提高了瘤胃细菌菌群多样性和Firmicutes和Prevotella菌丰度,表明日粮中添加0.3%的包被肉桂醛对犊牛生长性能无负作用,但可改变瘤胃微生物区系并调控瘤胃发酵模式。     

Potential N mineralization and availability to maize in black soils in response to soil fertility improvement in Northeast China

Purpose

Understanding the soil nitrogen (N) mineralization potential (N₀) and crop N availability during the growing season is essential for improving nitrogen use efficiency (NUE) and preventing over-fertilization, which lead to negative environmental impacts.

Methods

Five black soils with different levels of fertility were selected in Northeast China. The N₀ and kinetics of these soils were estimated through laboratory experiments at different incubation temperatures (15, 25, and 35 °C). N mineralization dynamics were simulated using field soil temperature according to the incubation results. Moreover, the N uptake dynamics of maize were simulated according to the literature.

Results

Compared with the very low-fertility soils, the cumulative mineralized nitrogen increased under all incubation temperatures (15, 25, and 35 °C), by 48–136%, 8–61%, and 24–59%, respectively, in the medium- and high-fertility soils. The highest N₀ values (96.90, 115.31, and 121.33 mg/kg at the three different temperatures) were recorded in the very high-fertility soils. The soil N mineralization dynamics and N uptake of maize in the growing season were highly consistent over time, although the soil N supply could not meet the maize growth requirements. The higher the soil fertility, the lower the N fertilizer requirement.

Conclusions

Different fertilizer strategies were developed based on the cumulative mineralized N, N uptake by maize, and NUE in soils with different fertility levels. We suggested a reduction of 50–65 kg N/ha in N fertilizer in the two highest fertility soils. This study provided basic data to reduce chemical N fertilizer to improve NUE and reduce negative environmental impacts.

     

番茄颈腐根腐病抗性鉴定技术的建立及抗性种质资源筛选

[目的]探索番茄颈腐根腐病(Fusarium crown and root rot,FCRR)苗期抗性鉴定技术,并对番茄种质资源及品种进行抗性鉴定分析,挖掘和丰富可利用的抗性资源,为培育抗颈腐根腐病番茄品种打下基础.[方法]以尖镰孢番茄颈腐根腐病专化型病原菌(Fusarium oxysporum f.sp.radici...     

木霉菌和白腐菌对水稻秸秆降解的影响

通过差重法进行定量测定,研究了康宁木霉和白腐菌株黄孢原毛平革菌对水稻秸秆降解的影响及其降解规律。结果表明:秸秆发酵过程中纤维素、半纤维素、本质素在前28 d降解的很快,之后降解减缓。木霉菌和白腐菌配合使用降解效果最好,在70 d内纤维素被降解38.18%,半纤维素被降解53.99%,木质素被降解33.91%。     

重组禽流感病毒H7N9 H7-Re1株培养条件的优化

【背景】高致病性禽流感疫情的暴发造成了巨大的经济损失和环境卫生的破坏,现阶段疫苗接种仍是我国控制禽流感的主要措施之一,需要大量安全、高效和低成本的禽流感病毒疫苗。鸡胚法制备禽流感病毒疫苗的工艺存在原料来源受限、过程复杂、个体差异、培养周期长和不易放大培养等缺陷。而利用生物反应器大规模培养动物细胞生产病毒疫苗,不仅可以大幅度提高单位产量,实现高密度细胞和高病毒产率,同时可保证产品质量。目前我国用于禽流感防控的疫苗为重组禽流感病毒(H5+H7)二价灭活疫苗(H5N1 Re-8株+H7N9 H7-Re1株)。国内细胞全悬浮工艺生产禽流感灭活疫苗单罐产能最大为6 000 L,高病毒含量抗原的提供是生产高效疫苗的主要影响因素之一。【目的】为了能够提供稳定的、高效的生产抗原,开展种毒驯化试验。【方法】将重组禽流感病毒H7N9 H7-Re1株分别在MDCK细胞及悬浮MDCK细胞上增殖。在MDCK细胞上通过不同的病毒接种剂量、不同收获时间、不同TPCK-胰酶浓度的试验,确定了H7N9 H7-Re1株在MDCK细胞上最佳收获时间为64 h,最佳接毒剂量为0.008%或MOI为10~(-4),最佳TPCK-胰酶浓度为2μg·mL~(-1),根据确定的最佳培养条件连续传代,并对各代次病毒含量进行检测。【结果】在MDCK细胞上传至第5代时,HA可达1﹕256,每1 mL病毒含量达到10~(8.5)TCID50,每0.1 mL病毒含量达到10~(8.5)EID50,均高于其他代次。【结论】将第5代确定为MDCK细胞传代最佳代次,可考虑确定为生产用基础种毒代次。在悬浮MDCK细胞上对重组禽流感病毒传代进行了优化试验,确定了H7N9 H7-Re1株在悬浮MDCK细胞上最佳收获时间为48 h,最佳接毒剂量MOI为10~(-2),最佳TPCK-胰酶浓度为4—8μg·mL~(-1)。在实际疫苗生产过程中,可选择MDCK细胞或悬浮MDCK细胞来扩繁种毒。