Expression of hypoxia-inducible factor 1 and neuroglobin in piglet cortex during deep hypothermic circulatory arrest

AIM: To observe the expression of hypoxia-inducible factor 1 (HIF-1) and neuroglobin (NGB) in piglet cortex during deep hypothermic circulatory arrest. METHODS: Wuzhishan piglets were randomly assigned to cardiopulmonary bypass group (CPB group), 40 min of circulatory arrest (CA) at 18 ℃ without cerebral perfusion (DHCA group) or with selective antegrade cerebral perfusion (SACP group). After 180 min of reperfusion, cortical tissue was harvested for determining HIF-1α and NGB expression by HE staining, Western blot and real-time PCR. RESULTS: Severer cerebral injury was observed in DHCA group than that in SACP group. After 180 min of reperfusion, HIF-1α protein and mRNA levels were significantly higher in DHCA group than those in CPB group (P<0.05). Accordingly, SACP animal had higher levels of HIF-1α protein and mRNA than those in DHCA group (P<0.05). Simultaneously, higher NGB protein and mRNA levels were found in DHCA group than those in CPB group after 180 min of reperfusion (P<0.05). The SACP animal had higher levels of NGB protein and mRNA than those in DHCA group (P<0.05). CONCLUSION: Up-regulation of HIF-1 and NGB are involved in the mechanism against cerebral injury resulting from DHCA in the cortex and possibly a part of cerebral protective effect of SACP.     

Breeding crops for reduced-tillage management in the intensive, rice–wheat systems of South Asia

The importance of reduced tillage in sustainable agriculture is well recognized. Reduced-tillage practices (which may or may not involve retention of crop residues) and their effects differ from those of conventional tillage in several ways: soil physical properties; shifts in host–weed competition; soil moisture availability (especially when sowing deeply or under stubble); and the emergence of pathogen populations that survive on crop residues. There may be a need for genotypes suited to special forms of mechanization (e.g. direct seeding into residues) and to agronomic conditions such as allelopathy, as well as specific issues relating to problem soils. This article examines issues and breeding targets for researchers who seek to improve crops for reduced-tillage systems. Most of the examples used pertain to wheat, but we also refer to other crops. Our primary claim is that new breeding initiatives are needed to introgress favourable traits into wheat and other crops in areas where reduced or zero-tillage is being adopted. Key traits include faster emergence, faster decomposition, and the ability to germinate when deep seeded (so that crops compete with weeds and use available moisture more efficiently). Enhancement of resistance to new pathogens and insect pests surviving on crop residues must also be given attention. In addition to focusing on new traits, breeders need to assess germplasm and breeding populations under reduced tillage. Farmer participatory approaches can also enhance the effectiveness of cultivar development and selection in environments where farmers’ links with technology providers are weak. Finally, modern breeding tools may also play a substantial role in future efforts to develop adapted crop genotypes for reduced tillage.     

免耕抛栽水稻源库特性研究

近些年来,水稻免耕抛秧栽培在中国广西等部分地区发展迅速。为了探讨免耕抛栽水稻产量形成特点,以金优253(OryzasativaL.)为试验材料,以常耕抛栽水稻为对照,从叶面积大小、剑叶光合速率与衰老、库的大小及源库比率等方面研究了免耕抛栽水稻的源库特性。结果表明,免耕抛栽水稻早、晚季产量分别为5.97t/hm2和7.53t/hm2,常耕抛栽水稻分别为6.19t/hm2和7.63t/hm2,其产量差异在早季和晚季均不显著。与常耕抛栽水稻相比,免耕抛栽水稻的每穗总粒数和单位面积上的总粒数较多,各生育期的叶面积指数较大,灌浆期剑叶光合速率、蒸腾速率、气孔导度、叶绿素含量较高,而过氧化物酶和过氧化氢酶活性及丙二醛的含量较低,在生理上存在一定的优势。但是,免耕抛栽水稻的源库协调能力较差,粒叶比和结实率下降,致使免耕抛栽水稻在产量上表现出一定的劣势。免耕抛栽水稻粒叶比和结实率的下降是由于其生产的干物质更多地分配在叶片中、贮藏在茎鞘中的干物质在抽穗后向穗部运转的能力较差造成的。     

Yield and quality components of silage maize in killed and live cover crop sods

In sloping areas with high precipitation, planting maize into live winter cover crop sods may help to alleviate the environmental problems associated with clean-tillage production systems of maize. The present study evaluates the performance of silage maize (Zea mays L.) under several cultivation methods: CC (conventional cropping system, i.e., maize was sown into the bare, autumn-ploughed soil); LGS/CK (maize was planted into a living Italian ryegrass (Lolium multiflorum Lam.) sod which was subsequently herbicidally killed); and LGS/MR (similar to LGS/CK, but the ryegrass was mechanically regulated). The research was conducted in the midlands of Switzerland on a fertile sandy loam under humid conditions during three cropping seasons. With 110 kg N ha⁻¹ (fertilizer nitrogen plus mineral nitrogen of the soil at maize planting), the CC system was much more productive than were the LGS/CK and LGS/MR systems in terms of dry matter and nitrogen yields of maize. Increasing the nitrogen supply to 250 kg N ha⁻¹ considerably reduced the yield advantage of CC over the LGS/CK and LGS/MR systems, indicating that nitrogen was the most limiting factor for maize yield in the mulch seeding systems. With 250 kg N ha⁻¹, the LGS/CK and LGS/MR systems produced greater total yields of digestible organic matter (maize plus ryegrass) than did the CC system, whereas the total nitrogen yield was similar for all cropping systems. The whole-shoot concentrations of nitrogen were highest under CC, irrespective of the level of nitrogen supply. With 110 kg N ha⁻¹, concentrations of phosphorus and magnesium were clearly higher for the mulch seeding systems. There were only minor differences among the cropping methods in the concentrations of potassium and calcium in the whole shoot. When 250 kg N ha⁻¹ were applied, there were no significant variations among the cropping systems in the concentrations of minerals. Changes in the botanical composition of the cover crop sod and in the time and method of cover crop control may help to reduce the competition for nitrogen between maize and the living mulch.     

肥料深施对小麦生育性状、养分吸收及产量的影响

几年来在豫东潮土地区砂质土上进行的肥料深施效果试验研究结果表明,肥料深施对小麦的生育状况和经济性状有较大影响,肥料深施与浅施比较,可使小麦植株前期生长健壮,中后期生长稳健,落黄好,穗大粒多,籽粒饱满。可显著增加小麦养分吸收量,提高化肥利用率,肥料深施处理比浅施处理氮、磷、钾的吸收量,分别增加34.32￣67.81kg/hm2,3.22￣9.42kg/hm2和17.82￣39.84kg/hm2;氮素化肥利用率提高20.86￣41.1个百分点,磷肥利用率提高7.13￣15.39个百分点;肥料深施在小麦田里养分残留量较浅施的高,尽管一季小麦对土壤有机质耗竭不大,但对氮、磷素的残存已有差异。肥料深施对小麦产量、经济效益、化肥利用率有显著的影响,采用肥料深施技术比群众习惯施肥方法(浅施)可增产小麦337.1￣1183.5kg/hm2,增产率达7.6%￣26.6%,增加收益539.36￣1893.6元/hm2。     

紫色丘陵区保护性耕作条件下水稻优化施肥模式研究

应用二次正交回归旋转组合设计方法,研究了紫色丘陵区保护性耕作下麦秆还田量、施氮量(N)、施磷量(P2O5)、施钾量(K2O)和氮肥施用次数的主效应和交互效应与水稻产量的关系。结果表明:保护性耕作下水稻最高单产8722.5kg/hm2,偏离平均单产1101kg/hm2,最低单产7222.5kg/hm2,偏离平均单产1344kg/hm2,试验田水稻施肥技术代表了本区域水稻生产实际情况,能提炼出符合本区域大田生产的高产、高效科学施肥方法。根据回归模型得出3125种配方施肥方案,从中优化筛选出5套方案,而最优化方案为:2hm2麦田的小麦秸秆还田于1hm2稻田中,每公顷施纯氮270kg、磷90kg、钾45kg,施氮量按底肥、分蘖肥、拔节肥、穗肥、粒肥5次各60%、10%、10%、10%、10%施用,钾肥底肥、穗肥各50%,可获得单产约9450kg/hm2,每公顷收益可达12600元左右,收益比为6.42。农田保护性耕作措施是非常切合时宜的,是培肥地力,改良土壤,优化农田生产小环境,保证耕地可持续生产的得力措施。     

坡耕地耕作管理措施对降雨入渗的影响

利用人工模拟降雨装置对坡耕地不同耕作管理措施强化降水入渗规律进行了研究。结果表明,不同耕作管理措施强化降水入渗速率效用不同,在相同入渗时间情况下,强化降水入渗速率等高耕作>人工掏挖>人工锄耕>直线坡,在中小雨强和较短降雨历时情况下,这种情况表现更为显著。在对黄土高原超渗产流理论和坡面水量平衡方程分析的基础上,得出了不同耕作管理措施强化降水入渗速率与入渗时间的函数关系式。     

采用PLS-DA分析毛火方式对工夫红茶品质的影响

为探究不同毛火方式对工夫红茶品质的影响,明确新型电磁内热式滚筒-热风耦合干燥设备的毛火效果,该研究以一芽一二叶初展嫩度的"福鼎大白"品种为原料进行工夫红茶加工,设定电磁滚筒-热风耦合(Rotary pot-Hot air coupling First-Drying with electromagnetic heat,RHFD)、链板热风(Chain plate Hot air First-Drying,CHFD)、箱式热风(Box Hot air First-Drying,BHFD)、滚筒式滚炒(Rotary pot First-Drying,RFD)等4种毛火方式,比较所制茶样的茶多酚、儿茶素、茶色素、可溶性糖、咖啡碱、氨基酸等29个非挥发性指标,114个气相色谱-质谱技术(GasChromatography-Mass Spectrometry,GC-MS)检测的挥发性香气指标,10个外形和汤色色泽客观评价指标,同时进行了毛火方式的热效率、生产效率、生产成本等性能指标的分析比较,通过偏最小二乘判别统计(PartialLeastSquaresDiscriminationAnalysis,PLS-DA)分析毛火方式对优质工夫红茶品质的影响,并获得标志性差异化合物。结果表明:电磁内热式滚筒-热风耦合毛火处理下茶多酚和儿茶素总量显著最低(P<0.05),简单儿茶素含量较高,茶红素和可溶性糖含量、茶黄素综合指标TDE和茶色素综合指标10TFRB最高(P<0.05),毛火方式对茶黄素总量影响不显著(P>0.05);挥发性化合物总量以RHFD方式最高,RFD方式次之,CHFD方式最低;RHFD毛火方式芳香类、萜烯类等化合物含量最高。电磁内热式滚筒-热风耦合毛火升温快、温度分布均匀且稳定性好,热效率和生产效率高(分别为50.0%、220 kg/h),生产成本较低(仅0.32元/kg),预热时间仅14min;所制红茶在汤色透亮度、香气甜久度、滋味甜醇度等方面均得到提升,感官总分最高(P<0.05),达88.1。PLS-DA分析从挥发性和非挥发性角度均可将工夫红茶4种毛火方式显著区分,并分别获得了43种和18种差异化合物,结合差异性分析获得标志性差异化合物,2,4,6-三(1,1-二甲基乙基)-4-甲基环己-2,5-二烯-1-酮、香叶醇、3-辛酮、水杨酸甲酯、茶黄素、茶褐素、可溶性糖、表儿茶素等,可作为区分工夫红茶毛火方式,以及定向加工甜香、甜醇、高亮等优质工夫红茶的指标物质。该研究为红茶加工基础和品质提升提供技术参考和理论指导。     

山地幼龄茶园夏秋季免耕栽培技术研究

在重庆山地茶园中,主要研究了夏秋季免耕栽培技术及其对水土流失的保持效果,并提出:夏秋季离地4~7 cm时修剪杂草1~3次,既可有效控制水土流失、又能降低管理成本,是实行免耕较为理想的杂草管理模式;茶树行间10月种植绿肥翌年5月翻埋并配施追肥,可改良土壤结构,增加土壤养分,提高茶树生长势,形成土壤培肥模式。两种管理模式的配套,既培肥土壤又很好地控制了土壤侵蚀问题,是山地幼龄茶园较好的保持可持续发展的栽培技术及管理模式。     

松嫩平原水资源可持续利用战略探讨

分析了我国北方荒漠化形势和实施农田保护性耕作对防止沙尘暴的作用和意义。根据生态学原理,提 出了加强农田防护林建设和实施留茬、免耕、覆盖等保护性耕作技术措施以及加强农田防沙配套技术体系研究 的一些设想。