控制性交替隔沟灌溉对夏玉米生理特性和水分生产效率的影响

2008年6～9月在河南新乡进行了不同沟灌方式和水分处理下(质量比占田间持水率的80％、70％、60％)夏玉米生理特性和生产效率的试验研究.结果表明:交替隔沟灌溉有效抑制冗余生长,使光合产物向有利于产量形成方向运转,灌水量均减小33.3％,耗水量降低22.04％、21.05％和23.88％,减产2.85％、3.99％和...     

中华蜜蜂细胞吞噬与包囊作用相关基因全长转录本鉴定及分析

【目的】系统鉴定和分析中华蜜蜂(Apis cerana cerana)吞噬与包囊作用相关基因和全长转录本,为深入开展相关基因和剪接体的功能研究奠定基础。【方法】基于前期已获得的高质量中华蜜蜂纳米孔长读段测序数据,通过Blast工具将全长转录本比对Nr数据库筛选出吞噬与包囊作用相关基因和全长转录本。利用gffcompare软件将全长转录本与东方蜜蜂(Apis cerana)参考基因组上注释的转录本进行比较,鉴定未注释的新基因和新转录本。利用TAPIS pipeline预测和分析吞噬与包囊作用相关基因的可变多聚腺苷酸化(alternative polyadenylation,APA)位点,并通过TBtools软件鉴定APA位点上游的基序(motif)。使用Astalavista软件鉴定可变剪接(alternative splicing,AS)事件,并通过IGV浏览器进行结构可视化。通过RT-PCR验证AS事件的真实性。【结果】共鉴定到中华蜜蜂吞噬与包囊作用相关的基因66个和全长转录本395条,发掘出东方蜜蜂参考基因组未注释的2个新基因和303条新转录本。对参考基因组已注释的34个基因进行了结构优化,分别延伸了18个基因的5′端和12个基因的3′端,同时延长了4个基因的5′端和3′端。共鉴定到含有1个及以上APA位点的吞噬与包囊作用相关基因47个,其中多于5个APA位点的基因最多,为32个。在APA位点上游鉴定到多个基序,一致性序列为：GRBGCNKSDAACAAYTRBGCBMRNGGBYAYTAYWCNVWNGG。共鉴定到吞噬与包囊作用相关基因的AS事件296次,其中包括131次可变3′端剪接(alternative 3′splice site,A3SS)、85次内含子保留(intron retention,IR)、70次可变5′端剪接(alternative 5′splice site,A5SS)和10次外显子跳跃(exon skipping, ES)。RT-PCR结果显示,扩增的目的片段大小符合预期,证实了随机选择的2次AS事件的真实性。【结论】系统鉴定了中华蜜蜂吞噬与包囊作用相关基因和全长转录本以及AS事件和APA位点,优化了东方蜜蜂参考基因组注释的吞噬与包囊作用相关基因的结构。     

草菇谷胱甘肽过氧化物酶编码基因vv-gpx01的序列特征及表达分析

依托草菇基因组及转录组数据,克隆得到1个谷胱甘肽过氧化物酶(GPx)编码基因,命名为vvgpx01。ZOOM软件的分析结果表明:该基因全长1 313 bp,含有4个外显子、3个内含子,编码228个氨基酸;5'端非翻译区长为12 bp,3'端非翻译区为452 bp;其中3个内含子在RNA加工过程中均存在保留现象。生物信息学分析结果表明:草菇的GPx01序列具备完整的谷胱甘肽过氧化物酶保守结构域;系统发育树显示,担子菌与子囊菌的GPx分别聚在了2个不同的分支上,草菇GPx01与双孢蘑菇亲缘关系较近并与其他伞菌目的真菌聚在1个分支上。另外,由内含子保留所产生的氨基酸序列均出现了不同程度的功能域缺失,这将导致谷胱甘肽过氧化物酶的失活。表达谱分析结果表明:vv-gpx01在整个草菇生长阶段都有表达,但表达量存在差异。推测,草菇GPx01可能通过可变剪接产生不同的转录本,通过调节不同转录本的表达水平来调控基因功能域的翻译水平及空间构型,最终实现酶活性的调节。     

甘蔗螟虫生物防治策略展望

综述了甘蔗螟虫生物防治的主要策略及研究进展,并探讨了运用RNA干扰技术防治甘蔗螟虫的新策略,为通过转基因技术创制抗甘蔗螟虫新种质提供理论参考。     

Nonwithdrawal Molting Programs

In the commercial egg industry the management practice of using feed withdrawal to induce a flock to molt has been under extreme scrutiny. This is because animal rights groups have voiced their concern about using this practice. Thus, about 5 yr ago, the United Egg Producers (UEP) commissioned 5 universities to conduct experiments to develop alternative molting programs that used nonwithdrawal feeding programs to molt laying hens. The studies conducted to date used techniques ranging from feeding hens without added salt in the diet to using readily available, low-cost feed ingredients to develop molt diets that are low in energy level and protein content. The results of these studies indicated that molting laying hens without feed withdrawal could be done successfully. Research at the University of Illinois found that feeding laying hens diets consisting of wheat middlings, soybean hulls, and corn (low protein and low energy) were successful in providing for acceptable postmolt egg production performance and economic benefit compared with using a standard feed withdrawal method. Therefore, after 5 yr of experimenting with nonwithdrawal molting methods done in several university settings, the egg industry has successfully adopted these methods of molting laying hens. In addition, based on the finding of these experiments, the UEP has revised their recommended molting guidelines to state that only nonwithdrawal molting methods will be permitted after January 1, 2006. Thus, these guidelines will apply to approximately 82% of the US egg industry.     

水肥交互作用对稻田氮素利用率和氮素平衡的影响

采用蒸渗仪方法和同位素示踪技术研究了稻田常规灌溉和节水灌溉条件下不同施肥水平和施肥方式的氮素利用率和氮素平衡,结果表明:稻谷氮素累积量占植株氮素累积量一半左右,间歇灌溉模式和传统淹灌模式氮素累积量的差异反应在茎和绿叶和实粒,而在黄叶和秕粒中差别不大;差值法测得氮肥利用率比同位素法偏高,但二者均表现为间歇灌溉氮肥利用率高于淹灌模式,且间歇灌溉模式下低氮水平氮肥利用率高于高氮处理;根据同位素示踪法计算氮素平衡,氮素在稻田系统中的分配为氨挥发和反硝化占37.4%~51.7%,土壤残留占20.4%~37.7%,作物吸收占9.2%~36.4%,淋失占0.3%~16.4%。     

不同灌溉方式对大豆性状、产量及品质的影响

为了探讨辽宁中部地区大豆节水优质灌溉模式,在有滑动遮雨棚的测坑中进行田间试验,研究了常规沟灌、固定沟灌和交替沟灌3种灌溉模式对大豆的性状、产量及品质的影响。研究结果表明,交替沟灌比常规沟灌、固定沟灌更能促进大豆的根和茎粗的生长;其水分利用效率比常规沟灌和固定沟灌分别提高了25．4％和13．3％,产量提高了13．0％和7...     

Effects of isothiocyanates on purple (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.)

Purple and yellow nutsedge are two of the most troublesome weeds in the world. In the south-eastern USA, both weeds are common in vegetable crops and are the most difficult weeds to control in this region. A greenhouse experiment was conducted to evaluate the herbicidal activity of five liquid isothiocyanates (ITCs) (benzoyl, o -tolyl, m -tolyl, tert -octyl, and 3-fluorophenyl) on purple and yellow nutsedge. All ITCs were applied to soil in jars at 0, 100, 1000, 5000, and 10 000 nmol g⁻¹ of soil and sealed for 72 h to prevent gaseous losses, followed by nutsedge growth evaluations after an additional 18 days. All ITCs reduced purple and yellow nutsedge shoot density and shoot biomass over the concentrations evaluated, with differences in the effectiveness on each species apparent among the compounds. Based on the lethal concentration values for shoot density, all ITCs were more effective in suppressing purple nutsedge than yellow nutsedge. Benzoyl and 3-fluorophenyl were generally the most effective of the five ITCs evaluated.     

Balancing protein ingredients in carp feeds to limit dischargeof phosphorus and nitrogen into water bodies

ABSTRACT:   Through a series of experiments, it has been demonstrated successfullythat an appropriate choice of ingredients is primary for achievinga reduction in phosphorus (P) and nitrogen (N) loading from carpculture. In this final study, four multi-ingredient diets were examined.In addition to the basal ingredients (fish meal 15%, corngluten meal 8%, defatted soybean meal 10%, blood meal3–5%), three of the test diets (PF, MM, and SP)contained 6% each of either poultry feather meal, meatmeal or soy protein concentrate, respectively, and the fourth diet(PMS) had each of the three aforementioned ingredients includedat 3%. These diets had crude protein < 35%,digestible energy > 3.5 kcal/g,available P between 0.65 and 0.66% and total P rangingfrom 1.26 to 1.36%. The diets were fed to juvenile carpduring a 12-week feeding trial. The highest growth was obtained forfish fed the MM diet. The absorption and retention rates of P werehigher for the PF diet, whereas these values for N did not showtreatment-related differences. The total discharges per ton fish productionwere estimated to range between 7.8 and 9.2 kg for P andbetween 39.1 and 40.7 kg for N. These were lower than thefigures for Lake Kasumigaura, a main carp culture site, indicatingthat proper balancing of protein ingredients aids in efficientlylowering emissions from aquaculture.     

土传病害防治技术进展及面临的挑战

近10年来, 随着人们对环境的关注, 绿色发展成为农业生产的主流。在土传病害的防治中, 要尽可能减少对环境和生态的影响, 同时保证取得更好的经济效益。因而, 一些环境友好的防治技术受到重视。农业防治技术如抗性品种利用和嫁接、阻截传播、深翻、轮作和无土栽培; 生物防治技术如生物熏蒸、厌氧消毒、生物防治制剂等; 物理防治技术如太阳能消毒、火焰消毒、微波消毒、电消毒、射频消毒也在不断地创新; 化学防治技术主要依赖土壤熏蒸剂, 一些新型的环境友好的熏蒸剂如异硫氰酸烯丙酯、二甲基二硫、乙二腈、乙蒜素等也在不断发展。熏蒸剂新剂型、新的施药机械也在不断创新。土壤熏蒸剂在防治土传病害时, 也会对土壤中的微生态造成不同程度的影响。此外, 我们也应该清醒地认识到任何技术都有两面性, 并正视不同防治技术中的不足。土传病害作为一类难以防治的病害, 也面临着巨大的挑战, 高传染性要求有高质量的种苗和高效的防治和阻隔技术, 土传病害的定量检测技术, 土壤中的病原菌数量与发病的关系、土壤微生态对发病的影响都是亟待研究和解决的问题。在防控土传病害时, 如何减少温室气体的排放、减少防治投入以及塑料薄膜的污染均为面临的环境和经济学挑战。