猪血浆转铁蛋白与部分经济性状关系的研究——Ⅰ. 多态性与产仔数和日增重的关系

用经改进的聚丙烯酰胺凝胶电泳铁染法,测定了二花脸猪血浆转铁蛋白多态类型,分析了其基因型频率和基因频率,并探讨了猪血浆转铁蛋白多态性与产仔性能和增重速度的相关性。     

Reproductive roles predict sexual dimorphism in internal and external morphology of lake whitefish,Coregonus clupeaformis

Abstract – The different reproductive roles of the sexes can predict the direction and magnitude of sexual dimorphism of external and internal morphology. Males should have enlarged structures that enhance the acquisition of mating opportunities, whereas females are predicted to have enlarged organs that are associated with the production of eggs. We tested these predictions in male and female lake whitefish, a species in which both sexes have similar overall body size and shape. After controlling for body size, male lake whitefish had significantly longer jaws and pectoral and pelvic fins, larger hearts, and more muscle than females. Sexual dimorphism in relative muscle mass may be one of the most fundamental morphological differences between males and females. Females had relatively heavier livers than males. Because the liver is important for the breakdown of fats and vitellogenesis, selection should favour an enlarged liver in females for the processing of energy and the production of large numbers of eggs.     

农业土地规模经营的理论探讨

实现农业土地规模经营,有利于生产力有效运转并取得最佳的规模效益。其适度性受各种因素的影响,具有区域性和动态性。规模经营与劳动生产率有着密切的关系,应该在确保提高土地生产率的基础上来提高劳动生产和土地规模经营的效益。土地适当集中、土地经营主体的总人数尽量精简和劳动组合的优化是优化土地经营规模的三个相互制约的因素。要采取积极的措施逐步实现土地的规模经营。对现有土地经营形式要做具体分析,其调整应从有利于生产力发展出发,在尊重群众意愿的基础上稳步进行。     

Osmolarity,cell volume and proliferation in nasopharyngeal carcinoma cells

AIM: To investigate the relationship between osmolarity, cell volume and cell proliferation in nasopharyngeal carcinoma cells. METHODS: MTT method was applied to detect the proliferation ability of the poorly-differentiated nasopharyngeal carcinoma cell (CNE-2Z) under various osmolarity conditions. The flow cytometry was used to analyse cell cycle distribution. Cell volume was obtained by the image analysis of living cells and cell viability was determined by the trypan blue assay. RESULTS: Cultivation of cells under the hypertonic conditions of 370 and 440 mOsmol/L increased cell volume by 8.7% and 27.8% and facilitated cell proliferation by 22.2% and 33.9%, respectively. However, hypotonic incubation of cells with osmolarity of 160 and 230 mOsmol/L decreased cell volume by 12.8% and 4.1% and inhibited cell proliferation by 34.0% and 15.6%, respectively. Cell volume was positively correlated with cell proliferation rate. Long-term cultivation of cells under anisotonic conditions did not significantly alter cell cycle distribution, but hypotonic cultivation decreased cell viability. CONCLUSION: Proliferation of nasopharyngeal carcinoma cells was closely correlated with the osmolarity of culture medium and cell volume. Hypotonic cultivation may inhibit cell proliferation by decreasing cell volume to facilitate cell death mechanisms.     

Evaluation of sampling methods and assessment of the sample size to estimate the weed seedbank in soil, taking into account spatial variability

As field sampling is time consuming, it is necessary to develop efficient sampling techniques to obtain accurate estimates of the weed seedbank in soil. The relative efficiency between sampling schemes depends on the spatial variability in weed seed density across agricultural fields. Spatial variability of the weed seed density was characterized by theoretical correlograms. A systematic sampling (square grill) scheme was considered and it was found that, taking into account spatial variability, this sampling scheme was more efficient than simple random sampling. As a result, the sample size can be reduced in comparison with that given in previous studies, where spatial correlation was ignored. The reduction depends on the correlation structure defined as a function of the ratio, τ, between the nugget effect and the sill of the variogram. The maximum reduction of the sample size, without loss of either precision or confidence level corresponds to the case where there is no nugget effect, τ = 0. The opposite extreme case, where the reduction is nil, corresponds to the case of a pure nugget effect τ = 1. The abaci based on given expressions are provided to determine the sample size in species whose spatial pattern can be fitted either to a Poisson or to a negative binomial distribution.     

鄂尔多斯高原中部5.8～4.5 Cal kaBP气候旋回的地层记录

通过对鄂尔多斯高原现代风成砂与PJHZ剖面沉积物粒度特征的对比分析,确定了剖面中4个层位(290~210,190~160,153.5~123.5,50~40 cm)基本属于风成砂沉积。结合粒度参数、碳酸钙含量、总有机碳含量及年代序列,认为此区域在5.8~4.5 Cal kaBP存在以下沉积旋回:~5 749 Cal aBP,沉积风成砂,反映该时期风砂活动强烈,气候干燥,冬季风强盛;5 749 Cal aBP前后,沉积物为灰绿色湖相层,表明这一时期存在短暂的湖面扩展,沙漠退缩;5 749~5 370 Cal aBP,沉积风成砂,反映了湖泊的退缩和沙漠的扩展;5 370~4 895 Cal aBP,湖相沉积物,反映了流域降水量的增多;4 895~4 580 Cal aBP沉积风成砂后,4 580 Cal aBP前后又出现了短暂的湖相沉积,之后又是风砂沉积。     

乳化剂对4.5%高效氯氰菊酯水乳剂 物理稳定性的影响

以4.5%高效氯氰菊酯水乳剂为研究对象,探讨了乳化剂的种类、用量、亲水亲油平衡值(HLB值)和结构对水乳剂物理稳定性的影响。结果表明:当乳化剂种类选定后,在一定用量范围内,水乳剂的粒径随着乳化剂用量的增加而变小,粒径分布范围变窄,稳定性增强,粒径大小可作为筛选乳化剂最佳用量的指标;乳化剂的HLB值与水乳剂的粒径及粒径分布范围关系密切;乳化剂的结构和水乳剂的乳液抗聚并性存在相关性,适当增加亲油性的饱和碳链长度,有助于提高水乳剂的乳液抗聚并性,进而获得稳定的水乳剂配方。     

七株植物内生放线菌对苹果树腐烂病的防治作用

通过分生孢子萌发试验、菌丝抑制试验、接种离体枝条试验及田间病斑涂抹药剂防治试验,研究了7株植物内生放线菌对苹果树腐烂病的防治效果。结果表明,7株植物内生放线菌无菌发酵滤液对病原菌分生孢子萌发及菌丝生长均有明显的抑制作用,2倍稀释液对孢子萌发抑制率均达85%以上,20倍稀释液对菌丝生长抑制率均达80%以上。显微观察发现,Hhs.015 (BAR1-5)菌株无菌发酵滤液可导致病菌芽管、菌丝畸形。在人工接种条件下,无菌发酵滤液原液对离体枝条病斑扩展具有明显的抑制作用,其中AR1-14、Hhs.015 (BAR1-5)和TGYXCSA-7处理5天后防治效果分别达83.2%、69.7%和85.6%。田间刮除病斑后涂抹放线菌发酵原液也可明显抑制病斑复发,防效均达80%以上。     

南亚实蝇成虫空间分布型及抽样技术

南亚实蝇Zeugodacus tau(Walker)是瓜果蔬菜上重要的检疫性害虫,常导致严重的经济损失。本文旨在明确其在主要寄主作物(丝瓜、“苦瓜-桂花”系统)上的空间格局,并根据最适理论抽样数制定了采样方案,以便为该虫管理决策提供科学依据。于2020年7月和9月分别在立架栽培的丝瓜地和“苦瓜-桂花”系统采用黄板诱捕实蝇类害虫,用非参数两独立样本t测验分析不同生境南亚实蝇雌、雄成虫种群密度的差异显著性,用2个常用的聚集度指标(C和k)和2个回归模型(Taylor幂回归模型和Iwao的m~*-m回归模型)分别分析雌虫、雄虫和“雌虫+雄虫”的空间格局。共诱集实蝇成虫3 542头,“苦瓜-桂花”系统只诱集到南亚实蝇,丝瓜地诱集到4种果实蝇,其中南亚实蝇占97.2%,为优势种。桂花树上的南亚实蝇雌虫种群密度显著高于苦瓜地(Z=-2.932,P=0.003),为后者的1.87倍;丝瓜地样地Ⅱ中的雌虫种群密度显著大于样地Ⅰ(Z=-7.160,P<0.001),为后者的3.13倍。回归分析表明,对雌虫,Taylor的b和Iwao的β与1无显著差异(t_c...     

食物氮含量对意大利蝗生长发育和卵巢面积的影响

为合理预测意大利蝗Calliptamus italicus的种群动态,分别用1%（对照）、4%和7%氮含量的食物饲喂意大利蝗5龄蝗蝻,测定不同氮含量食物处理后意大利蝗5龄蝗蝻的生长速率,羽化后7 d的体长、股节长、胫节长、翅长、翅宽、体重及羽化后1、7、13和19 d的卵巢面积。结果显示,4%氮含量食物处理试虫的生长速率最大,分别较1%和7%氮含量处理的增加了88.02%和109.33%;4%和7%氮含量食物处理后,意大利蝗成虫的后翅宽和体重均显著高于对照;羽化后7 d,不同氮含量食物处理的意大利蝗卵巢面积出现显著差异,羽化后19 d,4%氮含量食物处理的卵巢面积显著高于其他2个处理。表明中等氮含量（4%氮含量）适宜意大利蝗生长。