探析IPv6技术

阐述了IPv4现存在的一些问题和IPv6的一些优点,在此基础上对IPv6、DNS进行简单的介绍。     

Long-Term Effect of Fertilizer and Rice Straw on Mineral Composition and Potassium Adsorption in a Reddish Paddy Soil

Increasing K⁺ adsorption can be an effective alternative in building an available K pool in soils to optimize crop recovery and minimize losses into the environment. We hypothesized that long-term fertilization might change K⁺ adsorption because of changes in the chemical and mineralogical properties of a rice (Oryza sativa L.). The aims of this study were (i) to determine clay minerals in paddy soil clay size fractions using X-ray diffraction methods and a numerical diagram-decomposition method; (ii) to measure K⁺ adsorption isotherms before and after H₂O₂ oxidation of organic matter, and (iii) to investigate whether K⁺ adsorption is correlated with changes in soil chemical and mineral properties. The 30-yr long-term fertilization treatments caused little change in soil organic C (SOC) but a large variation in soil mineral composition. The whole-clay fraction (<5 μm) corresponded more to the fertilization treatment than the fine-clay fraction (<1 μm) in terms of percentage of illite peak area. The total percentage of vermiculite-chlorite peak area was significantly negatively correlated with the total percentage of illite peak area in the <5 μm soil particles (R=-0.946, P<0.0006). Different fertilization treatments gave significantly different results in K⁺ adsorption. The SOC oxidation test showed positive effects of SOC on K⁺ adsorption at lower K⁺ concentration (?120 mg L^?1) and negative effects at higher K⁺ concentration (240 mg L^?1). The K⁺ adsorption by soil clay minerals after SOC oxidization accounted for 60–158% of that by unoxidized soils, suggesting a more important role of soil minerals than SOC on K⁺ adsorption. The K⁺ adsorption potential was significantly correlated to the amount of poorly crystallized illite present (R=0.879, P=0.012). The availability of adsorbed K⁺ for plant growth needs further study.     

75%磺酰唑草酮干悬浮剂芽前防除蔗田杂草研究

75%磺酰唑草酮干悬浮剂分别以30、40、50、60g/667m²用量,芽前土壤处理防除蔗田马唐、牛筋草、狗尾草、香附子、胜红蓟、铜锤、苋菜等杂草。试验结果表明,药后30、60d株防效分别达73.1%～100.0%、66.7%～100.0%,总草防效分别为90.7%～98.7%、83.7%～97.6%;药后60d,鲜重防效达68.4%～100.0%,总草防效为87.8%～99.4%,对一年生单双子叶杂草表现良好的广谱性。药后30、60d总草株数和鲜重防效显著优于38%莠去津悬浮剂250g/667m²的效果。75%磺酰唑草酮干悬浮剂60g/667m²对甘蔗出苗和生长有一定的影响,但与其它处理无显著差异;50g/667m²增产率最高为12.79%;30g/667m²增产率最低,但也增产7.06%;其它处理增产均在9.05%以上,显著高于莠去津和人工除草。     

猪肺炎支原体膜蛋白P46基因在大肠杆菌中的表达

把猪肺炎支原体(Mycoplasma hyopneumoniae)国际标准株232的P46基因克隆进pGEM-T-EASY载体上,通过PCR方法把该基因中三个编码Trp的密码子TGA突变为TGG,然后将该基因亚克隆到载体pMAL-P2X上,得到重组表达载体pMAL-P2X-P46.用该重组载体转化大肠杆菌TB1,得到表达重组菌TB1-pMAL-P2XA-P46,用终浓度为0.3 mM的IPTG在37℃下诱导表达,获得可溶性表达的融合蛋白MBP-P46,在免疫印迹试验中,兔抗MBP高免血清和兔抗猪肺炎支原体高免血清都能与目的蛋白发生阳性反应,证明猪肺炎支原体P46基因在大肠杆菌里获得了可溶性表达.该融合蛋白对于建立特异性和敏感性好的EIISSA方法具有重要意义.     

乌兰布和沙漠流动沙丘不同部位水分动态研究

通过对乌兰布和沙漠流动沙丘的不同部位沙土含水量的测定研究，结果表明：（1）乌兰布和沙漠流动沙丘3个不同部位的水分垂直变化趋势是一致的，0～60cm含水量变化幅度大，60～100cm变化幅度小，含水量最大值出现在20～60CITI，降雨主要影响60cm以上的沙土水分；（2）3种部位在时间变化上都表现为4～5月含水量最小，从6月开始含水量升高；（3）迎风坡含水量较其他部位大0．65％～0．9％，较背风坡大1．8％～2．5％，其他部位较背风坡大1％～1．7％，且3种地貌部位20～60cm处较80cm和100cm处有较大差异，同时迎风坡的变化幅度最大。     

山西抗虫棉田棉花害虫发生特点及综合防治措施

1995年抗虫棉开始在山西省种植,因其对棉铃虫较好的抗性,深受广大棉农欢迎。近年来种植面积迅速扩大,目前全省抗虫棉种植面积占总植棉面积90%以上。我省推广的抗虫棉品种主要是新棉33B、GKl9、GK321等。抗虫棉的大面积种植,引起棉田生态系统发生变化,使棉田棉铃虫等鳞翅目害虫的为害得到有效控制,但棉叶螨、棉蓟马、棉盲蝽、烟粉虱等棉田次要害虫危害明显加重,上升为主要害虫。近年来,我们对新的生态条件下,棉田害虫发生规律及防治措施进行了一些调查和研究。1棉铃虫为害明显减轻1.1抗虫棉对棉铃虫产卵行为及卵孵化无不良影响据盐湖、临猗…     

Protective effect of ischemic preconditioning on rat retina with sustaining ischemia

AIM: To observe the effect of ischemic preconditioning (IPC) on the subsequent permanent ischemic rat retina. METHODS: A model of two-vessel occlusion (2VO) was used to give an ischemic insult to rat retina. Bilateral carotid arteries were occluded directly in the simple ischemic groups. A procedure of double 2 min ischemia- 3 min reperfusion was applied to IPC groups before their carotid arteries were occluded. Experimental control groups received the same operation except that their exposed vessels were not occluded. Other 6 normal rats served as immunohistochemical controls. Eyeballs were taken out after being subjected to 1, 3 and 7 days of ischemia. The morphometry of retina was measured by stereologic methods. The apoptosis during the retinal ischemia was detected by TUNEL. Immunohistochemistry staining was used for the localization of bcl-2 in retina. RESULTS: In IPC groups, the thickness of retina was thinner than that in simple ischemic groups. The apoptosis was less when compared with the simple ischemic groups at the same ischemic time. The apoptotic cells show only in INL and the apoptosis of RGCs was not appeared until 7 days postischemia. There was no significant difference of the numerical density of RGCs at the different time after the operation. The bcl-2 immunoreactivity was weaker than that of the simple ischemic groups too. CONCLUSION: IPC reduced the injury caused by ischemia in retina, showing a protective effect.     

节瓜蓟马的新天敌——中华微刺盲蝽

首次发现中华微刺盲蝽Campylomma chinensis Schwh捕食节瓜蓟马Thrips palmi Karny且对田间节瓜蓟马种群数量的减少起重要作用。本文研究了该虫的形态特征、捕食过程和取食范围。结果表明中华微刺盲蝽为多食性昆虫，能取食多种小型昆虫及多种昆虫的卵：在田间，中华微刺盲蝽与节瓜蓟马数量的跟随现象明显；通过释入盲蝽，能使节瓜蓟马种群数量减少。     

安哥拉山羊与建昌黑山羊及其杂种后代的DNA指纹分析

以 (CA/GATA/TCC) 5探针 ,HinfI酶切 ,研究安哥拉山羊和建昌黑山羊及安哥拉山羊与建昌黑山羊级进杂交的F2 、F3的DNA指纹图谱。结果 ,在供试山羊中 ,个体平均检出 1 8.2± 0 .4条谱带 ,安哥拉山羊、F2 、F3的鉴别机率分别为 1 .38× 1 0 - 12 ,1 .1 8× 1 0 - 13,0 .50× 1 0 - 10 ;群体内相似系数安哥拉山羊为0 .4 539,F2 为 0 .4 0 77,F3为 0 .61 1 1 ;亲子鉴定的父权概率W =0 .9889;安哥拉山羊与建昌黑山羊比较 ,2 .3kb和 8.6kb谱带为安哥拉山羊的特异谱带     

玉米雄性不育突变体mi-ms-3的遗传分析及分子鉴定

Maize is one of the best crops in the utilization of heterosis. Male sterile lines are important germplasms for the hybrids production. A male sterile mutant named mi-ms-3 was obtained by screening in a mutator insertion library. The number of male anthers in tassel decreased and not exserted. There were few anthers with only two pollen sacs in the mutant tassels, and some of the anthers were degenerated to membranous and formed filaments at their ends. Although pollens in the anthers could be stained by I₂-KI, pollen shedding was abnormal and the number of pollen grains decreased. The number of silks in the ear of the mutant increased, and there was a sterile grain on both sides of the maturated kernel. Fertility of F₁ plants, which were obtained by hybridization between mi-ms-3 and maize inbred Mo17, was normal. Genetic analysis of F₂ population showed that the mutant phenotype was controlled by a recessive gene. The candidate gene was preliminarily mapped on the long arm of chromosome 3 by BSA and it was located between a SSR marker and an Indel marker with a distance of 1.5 cM. There are 21 candidate genes in this region. It was finally found that the insertion mutation of Mu transposon occurred at 30 bp upstream of the coding region of zm00001d042618 (zmm16) by transponson tagging and sequencing analysis. The results showed that mi-ms-3 was a new allele of sts1, which caused by a single base mutation in the coding region. RT-PCR analysis indicated that the expression of zmm16 in the mutant was decreased. The identification of the new allelic mutant of sts1 in this study would provide new materials for the study of flower development and hybrid seed production.