硝酸稀土在优良牧草生产中的应用研究

稀土是牧草生产中一种重要的生长促进剂,在一定的有效浓度范围内对种子萌发、植株生长以及豆科牧草根瘤发育有明显的促进效果。通过以硝酸稀土(纯度为38％)为试验材料的研究表明,在河南省自然气候条件下,对禾草有效的稀土浓度为500 mg/kg,平均增产幅度为8.5％;对豆科牧草有效的稀土浓度为500-600mg/kg,平均增产幅度为8.8％,施用方法以浸种法最佳。     

In vitro growth inhibition effects of rhHGF/cHGF on SMMC-7721 human HCC cell line

AIM:To examine the effects of recombinant human hepatocyte growth factor(rhHGF) and native calf HGF(cHGF) on SMMC-7721 human hepatocellular carcinoma(HCC) cell line. METHODS:Human HCC cell line culture, photometric assay, and flow cytometric assay were used in this study .RESULTS:A similar type of dose-dependent cell growth inhibition effect on SMMC-7721 human HCC cells by rhHGF(5-20 μg/L) as well as by cHGF(25-100 mg/L) had been found, with the maximal effect at the highest concentration used. Approximately over 50% of the cells treated with rhHGF(5 μg/L, 10 μg/L, 20 μg/L) accumulated in the quiescent G₀/G₁ phase of the cell cycle over incubation periods for 3 d. CONCLUSION:The growth of SMMC-7721 human HCC cells was strongly inhibited by both rhHGF and cHGF. This might be because the cells exposed to HGF became arrested in the G₀/G₁ phase.     

早熟优质长豇豆新品种‘鄂豇豆2 号’

 ‘鄂豇豆2号’是经有性杂交选育而成的早熟蔓生豇豆新品种。该品种荚浅绿色, 长60 cm,单荚质量18~ 24 g。早熟, 荚商品性状优良, 产量高, 对光周期反应不敏感, 田间疫病、煤霉病、病毒病发病率低, 适宜于春、夏、秋各季栽培, 已在全国大部分省份推广种植成功。     

基于GIS的中国小麦条锈病菌越夏区气候区划

 基于多年的气象数据(1980~2001年),首次从制约小麦条锈病菌越夏的温度因子入手,结合寄主小麦因素,利用地理信息系统(Geographical Information System,GIS),对我国小麦条锈病菌越夏区进行较详细的气候区划。本研究从温度条件上明确了全国适合小麦条锈病菌越夏的范围。研究表明,在我国小麦种植区适合小麦条锈病菌越夏的范围很广。其中甘肃、四川、云南、陕西境内适合越夏的地区是连成一片的,甘肃东部除了西边的几个县外其它地方7、8月份最高一旬均温在20~23℃,条锈病菌越夏困难;西藏、青海境内的小麦种植区几乎都适合小麦条锈病菌越夏;贵州境内适合越夏的地区可能和云南越夏区是一个整体。云南适合越夏的地区甚广,且地形复杂,需要进一步调查研究。     

基于GIS的丹东地区柞蚕农业气候区划

根据当地柞蚕实际生产与气象条件的关系,确定了柞蚕生产的农业气候区划指标.运用丹东地区1:250000地形数据和丹东及周边地区气象站30年的气候资料,建立区划指标小网格推算模型,应用GIS技术对丹东地区柞蚕生产进行气候区划,将该区划分为气候最适宜区、气候适宜区、气候次适宜区和气候不适宜区,为丹东柞蚕生产的合理布局和发展提供参考依据.     

冷季放牧补饲对甘肃高山细毛后备母羊瘤胃代谢参数及瘤胃微生物数量的影响

旨在筛选出甘肃高山细毛羊后备母羊科学合理的补饲料,改变牧区由于营养供给不足导致甘肃高山细毛羊2.5岁才能配种的饲养方式。试验选择甘肃高山细毛羊(12月龄)48只,随机分为试验a(1号料)、b(2号料)、c(3号料)组和对照组(不补饲),进行90 d放牧补饲试验。结果表明,1)瘤胃pH试验a组和b组差异极显著(P<0.01)、c组显著(P<0.05)低于对照组,瘤胃氨态氮、蛋白氮、总氮浓度试验组均极显著高于对照组(P<0.01),总挥发性脂肪酸(VFA)试验a组和b组均极显著高于对照组(P<0.01),b组显著高于c组(P<0.05);乙酸和丙酸摩尔比a组极显著高于对照组(P<0.01),b和c组显著高于对照组(P<0.05);丁酸摩尔比a组极显著高于c组(P<0.01);乙/丙b组显著低于对照组(P<0.05)。2)瘤胃纤维降解菌和原虫数目试验组均极显著(P<0.01)或显著(P<0.05)高于对照组。综上所述,补饲均能正向影响甘肃高山细毛羊后备母羊瘤胃代谢参数及瘤胃微生物数量,以1号料补饲效果最优,2号料也能起到理想效果。     

Impact of cold-season grazing and supplementary feeding on rumen metabolic parameters and micro-organisms in the ewes of Gansu Alpine Fine Wool Sheep北大核心CSCD

An experiment was conducted to scientifically identify the appropriate feed for Gansu Alpine Fine Wool ewes in order to change the animals' breeding mode, which currently can only be mated at the age of 2.5 years due to insufficient nutritional supply. The experiment selected 48 12-month-old ewes and randomly divided them into group a (Diet 1), group b (Diet 2), group c (Diet 3), and a control group with no supplementary feeding. The feed test was run for 90 days. The rumen pH of groups a and b were very significantly higher (P<0.01) or group c significantly lower (P<0.05) than control group. The rumen ammonia nitrogen, protein nitrogen and total nitrogen of groups a, b and c were all higher than control group (P<0.01). The total volatile fatty acids of group a and b were all higher than the control group (P<0.01), group b significantly higher than group c (P<0.05). The molar ratio of acetic acid and propionic acid in group a was very significantly higher than control group (P<0.01), group b and c were significantly higher than control group (P<0.05). The molar ratio of butyric acid in group a was very significantly higher than group c (P<0.01). The ratio of acetic acid and propionic acid in group b was significantly lower than control group (P<0.05). The number of several rumen fiber-degrading bacteria and protozoa in groups a, b and c were very significantly (P<0.01) or significantly (P<0.05) higher than the control. In conclusion, this study shows that supplementary feeding can positively affect the rumen metabolic parameters and the number of several rumen microorganisms in Gansu Alpine Fine Wool ewes. In general, the effects of Diet 1 were the strongest, while Diet 2 also produced notable improvements. © 2018, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

多径衰落信道下OFDM系统的符号同步方法研究

由于在正交频分复用（OFDM）的系统中存在符号时间同步误差，为了消除这种误差，提出了工作在多径衰落信道的符号时间频移（STO）估计方法，即基于CP的符号时间偏移估计和基于训练符号的符号时间偏移估计，通过仿真对基于循环序列（CP）估计技术的最大似然法（ML）和基于训练符号的最小均方差异法（Classen）两类性能比较分析，在无载波频移条件下，ML算法精确度更高，当存在载波频移时，Classen算法精确度更高。     

提高二倍体马铃薯原始栽培种原生质体分离与分裂频率的研究

为获得较高的原生质体分离和分裂频率,试验以马铃薯二倍体原始栽培种‘47-33’‘5-19’试管苗叶片为材料,进行了原生质体游离和培养的研究.结果表明:培养21d的两品系试管苗叶片均在含有2.0%纤维素酶+0.5%果胶酶+0.25%离析酶,渗透压为0.35mol/L的酶解液中解离效果最好,原生质体产量分别为2.31×106个/gFW和2.52×106个/gFW;在28℃酶解温度条件下缓慢摇动14h或1h静置+13h缓慢摇动的,可促进叶片原生质体的大量释放.此外,1.0mg/L NAA+0.5mg/L 2,4-D+0.4mg/L BAP外源激素组合有利于叶片原生质体的分裂,‘47-33’‘5-19’原生质体一次分裂频率分别达到8.85%和12.56%.在0.35mol/L渗透压的液体培养基中,‘47-33’叶片原生质体分裂更早,分裂频率达13.85%.研究获得了稳定的原生质体分离体系以及较好的原生质体培养条件,为马铃薯二倍体原始栽培种的体细胞融合奠定了基础.     

近15年我国土地利用分区研究进展

通过查阅21世纪以来的大量文献和对比分析,总结了国内土地利用分区的研究动态。结果表明院国内土地利用分区类型呈多元化,以省、市、县级为尺度和采用聚类分析法、GIS技术的研究较多,基于个案研究提出了新的理论、方法模型等,有效地对土地利用分区进行了探索,但也存在问题和不足;并指出其发展趋势是分区理论深入化、分区制度完善化、分区方法集成化及信息化。