胶束分光光度法测定环境样品中的痕量锰     

陈同森  张建云 《湖南农业大学学报(自然科学版)》1993,20(4)

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基于果实相关性状的桃品种初级核心种质取样策略研究   总被引：5，自引：1，他引：4  

李银霞  高其洁  李天红 《果树学报》2006,23(3):359-364

以国家种质资源圃(北京)编目的558份桃品种的18个形态学和农艺学性状为基本数据,研究了桃品种初级核心种质构建的取样策略,包括总体取样比例的确定及取样方案的选择,以获得最佳的初级核心种质。本试验共设10%～90%9个总体取样比例;取样方案研究包括分组原则和组内取样比例的确定。结果表明,桃初级核心种质的适宜总体取样比例为10%;按品种类群分组结合多样性比例取样为构建桃初级核心种质的最佳取样方案;利用此取样策略从558份桃品种中提取56份作为核心样本,对其代表性进行检测表明所构建的初级核心种质能够很好地代表桃原始种质的遗传多样性。  相似文献   

植物样品采集·制备·储存及消解过程中存在问题分析     

韩张雄  李慧慧  宋琼  雷腾  刘杰 《安徽农业科学》2016,44(25)

结合目前单位所承接的植物样品检测任务的实际情况,分析了植物样品的野外采集、加工制备及消解过程中会遇到的几个问题,为准确测定植物样品中重金属元素以及客观评价植物重金属污染提供了保障。  相似文献   

Variation among stallions in sperm quality after single layer centrifugation     

Ziyad Al-Kass  Alexander Brown  Anders Johannisson  Theodoros Ntallaris  Jane M. Morrell 《Reproduction in domestic animals》2021,56(6):848-856

Although single layer centrifugation (SLC) selects robust spermatozoa from stallion semen, the effect of individual variation has not been studied in detail. The objective of this study was to determine the variation among stallions in the effects of SLC on sperm quality during cooled storage for up to 48 hr. Semen samples from seven stallions (18 ejaculates) were split, with one portion being used for SLC and the other serving as a control (CON). Sperm quality (kinematics, reactive oxygen species (ROS) production, membrane integrity (MI) and chromatin integrity) were analysed at 0, 24 and 48 hr using computer-assisted sperm analysis and flow cytometry. Sperm quality was better in SLC than in CON at all timepoints, especially chromatin integrity and MI (p < .0001 for both), and some categories of ROS production (e.g. proportion of live hydrogen peroxide negative spermatozoa, p < .0001), but the degree of improvement varied among stallions and type of ROS (p < .05–p < .0001). Total and progressive motility were also better in SLC samples than in CON at 24 and 48 hr (p < .0001), although the effect on sperm kinematics varied. The interaction of treatment, time and stallion was not significant. In conclusion, sperm quality was better in SLC samples than in CON, although there was considerable individual variation among stallions. The improvement in sperm quality, particularly in chromatin integrity, was clearly beneficial, and therefore the use of this technique would be warranted for all stallion semen samples.  相似文献   

Influence of four soil maintenance practices on Collembola communities in a Mediterranean vineyard   总被引：1，自引：0，他引：1  

Anglique Renaud  Nicole Poinsot-Balaguer  Jrme Cortet  Jean Le Petit 《Pedobiologia》2004,48(5-6):623-630

We studied the influence of four soil maintenance practices on Collembola communities in the soil of a Mediterranean vineyard: (a) postemergence herbicide with glyphosate; (b) postemergence and pre-emergence herbicides with glyphosate, terbuthylazine, diuron and oryzalin; (c) natural flora and (d) tillage to a depth of 10–15 cm. Total Collembola abundance, species diversity and species richness significantly varied between the four practices. Notably, the practice using postemergence and pre-emergence herbicides had significantly lower values. Identification of Collembola at species level allowed an interspecies comparison and revealed significant differences for the most common species between the four practices, with each practice being characterized by a different set of species. None of the species were found to be significantly more abundant in the plots treated with postemergence and pre-emergence herbicides.  相似文献   

Comparative study on dietary protein requirements for juvenile and pre‐adult gibel carp (Carassius auratus gibelio var. CAS III)          下载免费PDF全文

W. Ye  D. Han  X. Zhu  Y. Yang  J. Jin  S. Xie 《Aquaculture Nutrition》2017,23(4):755-765

Two 8‐week growth trials were conducted in indoor recirculation system to evaluate the protein requirements for juvenile (3.70 ± 0.20 g) and pre‐adult (85.2 ± 0.70 g) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets were formulated for each trial using fish meal and casein as protein sources, and protein level was 250–450 g kg^?1 in Trial 1 and 200–450 g kg^?1 in Trial 2. With the increasing dietary protein, feeding rate (FR) and feed conversion ratio (FCR) significantly decreased (P < 0.05). Weight gain (WG) increased first and then reached a plateau in 330–450 g kg^?1 in Trial 1 (P > 0.05), while decreased after the maximum value in 350 g kg^?1 in Trial 2 (P < 0.05). Productive protein values (PPVs) were lower in 370–450 g kg^?1 in Trial 1 and 400–450 g kg^?1 in Trial 2 (P < 0.05). Increasing dietary protein level increased protein content and decreased lipid content in whole fish body and white muscle (P < 0.05). Apparent digestibility coefficient of dry matters (ADC_d) decreased, while apparent digestibility coefficient of protein (ADC_p) increased in 370–450 g kg^?1 in Trial 1 and 250–450 g kg^?1 in Trial 2 (P < 0.05). Trypsin activity significantly increased in 370–450 g kg^?1 in Trial 1 (P < 0.05) and was not affected in Trial 2 (P > 0.05). Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in both trials increased when dietary protein was above 400 g kg^?1 (P < 0.05). Based on quadratic regression of WG, it was estimated that dietary protein requirement for maximum growth was 414 g kg^?1 (digestible protein of 376 g kg^?1) and 365 g kg^?1 (digestible protein of 324 g kg^?1) for juvenile (3.70 g) and pre‐adult gibel carp (85.2 g).  相似文献   

基于地理权重回归模型的土壤有机质空间预测   总被引：3，自引：0，他引：3  

王库 《土壤通报》2013,(1):21-28

准确了解土壤有机质的空间分布是合理施肥的重要前提,也是水土流失控制及保护环境的重要基础。利用113个土壤有机质样点数据,以海拔高度、土壤侵蚀强度、土地利用、比值植被指数、样点至河流的欧氏距离、亚铁矿物指数及坡度为参考因子,来尝试利用GWR(Geographically Weighted Regression)模型探索多重因素作用下的土壤有机质空间分布,并通过与普通线性回归(ordinary least squares,OLS)相比较,来了解GWR模型的精度,进而进行了土壤有机质的空间制图,并对其制图效果进行了评价。结果表明,与OLS模型相比,GWR预测模型它能显著降低AIC(Akaike Information Criterion)值,较大程度地提高模型的决定系数,并有效地减少模型的回归残差值。从制图的总体效果看,GWR模型的预测结果与实测值的吻合程度要优于OLS模型。文章还对利用GWR模型进行回归时的样点数量、因子筛选及因子定量化等方面进行了相应的讨论。  相似文献   

近红外多组分分析中异常样本识别方法     

尹宝全  史银雪  孙瑞志  王文狄 《农业机械学报》2015,46(S1):122-127

近红外光谱分析中,异常样本的存在严重影响定标模型的预测性能和适配性。基于 X / Y 联合的ODXY异常样本识别和剔除方法,提出并证明了一种专用于多组分分析的MODXY异常样本识别方法。实验采用80组玉米近红外光谱数据,利用不同异常样本识别方法剔除异常样本后建立玉米含水率、含油率、蛋白质含量和淀粉含量4种组分的偏最小二乘预测模型,采用预测均方差和决定系数作为评价指标比较所建模型的性能,检验MODXY方法在多组分分析中的异常样本识别能力。实验结果表明：在近红外多组分分析中,MODXY方法在大多数情况下具有更好的异常样本识别能力;MODXY方法和ODXY方法均有一定的适用范围,它们更适合于相应组分化学值的相对标准偏差较大的情况。  相似文献   

长白猪主要选育性状间的典型相关分析   总被引：10，自引：0，他引：10       下载免费PDF全文

徐宁迎  王先明  曹小英  王松均 《浙江大学学报(农业与生命科学版)》2000,26(5):563-566

对长白猪的3组14个性状进行了典型相关分析。其中生长速度包含4个性状,体尺包含6个性状,膘厚和外貌评分等包含4个性状。结果表明,生长速度与体尺性状的第一和第二典型相关系数达极显著水平,分别为0.647 8和0.353 1,占总相关的96.52%。生长速度与膘厚和外貌评分等性状的第一和第二典型相关同样达极显著水平,分别为0.925和0.241 7,占总相关的99.9%。体尺与膘厚和外貌评分等性状只有第一个典型相关系数达极显著水平,其典型相关系数为0.328 7,占总相关的75.59%。分析还表明在这些性状中起主要作用的性状有X1（二月龄体重）、X3（测定结束体重）、X7（胸围）、X10（腿臀围）、X11（背膘厚）、X12（校正膘厚）。  相似文献   

BiFeO3-SrBi2Nb2O9陶瓷的表征及复阻抗研究     

黄海  韩立波  顾豪爽 《长江大学学报》2007,4(4):43-45

对单相层状钙钛矿结构的xBiFeO3-(1-x)SrBi2Nb2O9(x=0,0.1)陶瓷进行了表征和复阻抗分析。结果表明,BiFeO3的掺入降低了SBN的烧结温度,陶瓷晶粒尺寸减小,致密度提高;在较高温度时,SBFN的电学响应主要来源于晶粒效应,而SBN的电学响应则是晶粒效应、晶界效应和电极与介质界面效应的共同作用。  相似文献