热应激对动物生殖机能的影响及其作用机理     

吴结革  茆达干 《家畜生态》2006,(6)

温度对动物生殖机能具有重要的影响,本文分别阐述热应激对雌性动物发情、受胎率、胚胎成活率、产仔数以及对雄性动物繁殖性能的影响,并提出了热应激对动物生殖机能影响的可能作用机理。  相似文献   

宰前运输对肥育猪胴体、内脏及肉质的影响   总被引：5，自引：0，他引：5  

张伟力  殷宗俊  王力克 《家畜生态》2001,22(3):20-23

本试验对 1 0头宰前运输应激的大长淮 (大白×长白×淮猪 )肥育猪 (试验组 )和5头宰前无应激的大长淮肥育猪 (对照组 )作了胴体、内脏及肉质测定。试验组与对照组在胴体性状和内脏重量 (心脏除外 )方面无显著差异。应激组和对照组的肌肉 p Hu和肉色评分分别为 5.50 ,2 .2 5和 5.88,3 .0 0 ,差异显著 (P<0 .0 1 )。试验组肉质有下降趋势。  相似文献   

钢管混凝土拱桥的施工监控技术   总被引：2，自引：0，他引：2  

苏继东  徐强 《农机化研究》2005,(1):227-228

钢管混凝土是由混凝土填入薄壁钢管而形成的一种组合材料。在桥梁结构上,钢管混凝土主要应用于拱桥。目前,大跨度钢管混凝土拱桥主要采用缆索吊装-斜拉扣定施工新技术,拱桥的线形通过实测每节钢管拱的标高及拱轴线位置,并借助扣索实施动态调整来保证。为此,介绍了钢管混凝土拱桥施工过程的监控技术,从而指导施工,以确保拱桥建成后满足设计要求。  相似文献   

变截面构件的剪应力计算   总被引：1，自引：0，他引：1  

申向东  姬宝霖  李平 《内蒙古农业大学学报(自然科学版)》1995,(4)

变截面构件的弯曲变形是实际构件常见变形之一，现行钢筋混凝土设计规范提供的和实际设计计算应用的剪应力计算公式未考虑截面变化的影响，有较大的误差。本文用材料力学方法推出考虑变截面影响的剪应力计算公式，以便在实际设计计算应用。  相似文献   

NaCl胁迫对4种豆科牧草萌发的影响   总被引：1，自引：0，他引：1  

张苏江  江承凤  李艳霞 《黑龙江畜牧兽医》2006,(3):13-15

为研究盐渍化对4种牧草种子盐胁迫下发芽成苗的影响,探索不同牧草种子盐胁迫下的萌发表现,试验借鉴农作物研究的理论和方法,并在实验室条件下用不同浓度的NaCl溶液对种子进行处理,并观察其萌发特性,以期为生产实践提供有用的依据,减少在生产中的损失,提高草业生产的经济效益。1  相似文献   

低氧胁迫下黄瓜幼苗根系多胺代谢的变化   总被引：23，自引：2，他引：23  

汪天  王素平  郭世荣  高洪波 《园艺学报》2005,32(3):433-437

 利用外源Spd、PAO 抑制剂研究了黄瓜幼苗根系在低氧水培时的生长状况以及内源PAs、H₂O₂ 含量和PAO活性的动态变化。结果表明, 外源PAs对低氧胁迫下黄瓜幼苗根系的生长有促进作用;低氧处理后3种PAs含量都明显上升, 外源Spd和PAO抑制剂增加了根系中的PAs含量, 降低了根系中H₂O₂ 含量, 减缓了低氧伤害; PAs为低氧胁迫的应激产物, PAO为适应酶类, 其活性随PAs含量的变化而发生变化。  相似文献   

Effects of Acclimate™ on the frequency and duration of aggressive sequence and growth performance in co-mingled, weaned pigs     

M. Amstutz  K. Bennett-Wimbush  T. Meek  S. Courtney 《Livestock Production Science》2005,95(3):243-246

Co-mingling weaned pigs often results in aggressive behavior which can result in injury and reduced performance. This experiment examined the effect of Acclimate™, a product reported to reduce equine aggression, on weaned pig aggression and growth performance. Weanling pigs (n=214, avg. wt.=5.93 kg) were blocked by weight, sex and litter (n=25) and randomly assigned to either Acclimate™ treatment or a control group. Acclimate™ treated pigs were marked on the nose, face and neck. Pigs were individually identified and videotaped to determine frequency of aggressive sequence (FAS) and duration of aggression (DOA) on an individual pig basis. Pig weights and feed consumption were used to determine feed intake, total weight gain (TWG), average daily gain (ADG) and feed to gain ratio (F/G). Differences between litter, sex and treatment for FAS, DOA, F/G and ADG were tested using GLM, SAS. Neither Acclimate™ treatment or sex had a significant effect on FAS, TWG or F/G. However, there was a trend towards reduced duration and intensity of aggression in Acclimate™ treated pigs (p=0.1). There was a significant effect of litter (p<0.01) and TWG (p<0.001) on FAS at both 1 and 3 weeks. Acclimate™ treatment of weaned pigs does not decrease FAS, but may decrease the intensity and duration of aggression without negatively effecting growth.  相似文献   

水稻旱作对其生长量和经济产量的影响   总被引：11，自引：0，他引：11  

黄文江  黄义德  王纪华  李金才 《干旱地区农业研究》2003,21(4):15-19

1998～1999年，研究了水稻旱作条件下，不同生育时期受水分胁迫后对作物生长量的影响。结果表明：不同指标对水分胁迫时期的敏感性不一，植株高度对抽穗期水分胁迫最敏感；单株绿叶面积和单株地上部干重对幼穗分化后期水分胁迫最敏感；根系干重和根冠比对幼穗分化前期水分胁迫最敏感；幼穗分化后期水分胁迫对经济产量影响程度最大，无效分蘖期水分胁迫对产量影响程度最小。  相似文献   

Variation in the development of secondary dormancy in oilseed rape genotypes under conditions of stress   总被引：6，自引：0，他引：6  

E J J Momoh  W J Zhou  & B Kristiansson† 《Weed Research》2002,42(6):446-455

Summary A substantial amount of seed is left in the fields before and during harvest of oilseed rape. Although this crop exhibits little or no primary dormancy, the absence of certain environmental cues that promote germination of imbibed seeds induces secondary dormancy. The work reported investigated the extent to which environmental stress conditions, including osmotic stress, low oxygen stress and anaerobiosis, induce secondary dormancy in oilseed rape, and examined the variation in development of secondary dormancy between and within genotypes. Osmotic stress was most effective in inducing dormancy. Anaerobic treatment produced very few dormant seeds, as did an atmosphere low in oxygen and high in nitrogen. The development of secondary dormancy under osmotic stress varied considerably between and within genotypes. Dormancy ranged from almost zero to about 60% for winter genotypes and about 85% for spring types. Within genotypes, variations occurred between seed lots and years of harvest. Temperature variations affected the percentage of dormant seeds. More dormant seeds were likely to be produced with incubation under water stress at 20 °C than at 12 °C. In winter genotypes, fewer dormant seeds were produced when incubation temperature and germination test temperatures differed. Thus, incubating at 20 °C and 12 °C, followed by germination tests at 20 °C and 12 °C, respectively, produced most dormant seeds. Also, in the winter genotypes, the potential development of secondary dormancy was positively correlated with the pattern and speed of germination of untreated seeds.  相似文献   

碳酸氢根和铵态氮共同对菜豆生长及养分吸收的影响   总被引：5，自引：1，他引：5  

田霄鸿  李生秀  宋书琴 《园艺学报》2002,29(4):337-343

 以菜豆为材料进行水培试验, 探讨了高浓度NH₄⁺-N与HCO₃^-共存介质对菜豆生长发育及其营养吸收的影响, 结果表明: ①以HCO₃^--N 为主要氮源时, 菜豆生长状况最好; 以NH₄⁺-N为主要氮源且无HCO₃^-存在时, 培养前期菜豆根系就发生受害现象, 叶片出现萎蔫; 但加入HCO₃^-后, 随着营养液中HCO3- 浓度从0 升高到13. 0 mmol/L , 菜豆长势逐渐改善, 表明HCO₃^-与NH4+ 以较合适的比例共存于介质中可明显减轻二者非共存对菜豆生长的抑制作用。② 同一处理, 菜豆整株对主要营养元素吸收量的次序为: N > K> P > Ca >Mg > Fe >Mn , 以NH4+2N 为主要氮源时, 随HCO₃^-浓度升高, 菜豆对N、P、Ca、Mn 的吸收量逐渐增大。③以NO_3^--N 为主要氮源, P、Fe、Mn 元素在根部出现累积, 而以NH₄⁺-N为主要氮源时, 随HCO₃^-浓度增加, N、P、Ca、Mn 在根部亦有累积现象。  相似文献