半干旱区四种典型豆科牧草群落生理生态的分异研究

在黄土高原半干旱地区,植物种群生态的改善是植被建设与生态修复的关键。通过人工植被调查,比较了四种豆科牧草的种群生长的生态差异,初步探讨了牧草生产力与种群生态的可能耦合网络机制。结果表明:基于四种豆科牧草种群的土壤水分含量和垂直下降分布规律,发现沙打旺与苜蓿为高生产力型,红豆草与胡枝子为低生产力型,这可能与它们水分利用状况和豆科牧草本身的固氮或氮沉积的氮汇与源转化调节有关。苜蓿植株生物量表现较高,与其多年生庞大根系充分吸收土壤深层水分有关,反映了根冠生长与土壤条件的耦合是导致遗传特性响应差异的重要原因,因此调整植物根冠关系以增强植物的抗旱适应能力理论上是可行的。相关分析发现生产力、根系生物量、土壤环境(水分和层次)为网络耦联相关,特别是90-100cm的土壤空间水分与根冠比成正相关,这可能说明这个层次(根系的浅层集中分布区)为土壤水库与土壤干层相转变的阈值界面。因此从干旱胁迫条件下建立的适应性生存对策上考虑,苜蓿适宜在干旱立地推广应用,不仅具水土保持功效,而且植被生产力高,应为黄土高原生态恢复和生态建设的重要参考物种。     

赣北丘陵区果园不同套种模式对退化红壤理化性质的影响

为了探讨丘陵区果园水土保持措施与土壤理化性质改良关系,通过5a的野外定位观测试验,研究了5种不同果园套种模式对退化红壤理化性质的影响.研究结果表明:果园不同套种模式对土壤理化性质的改善效果不同,百喜草全园覆盖和狗牙根全园覆盖提高土壤含水量效果最好,全园套种狗牙根模式改良土壤容重、毛管持水量、有机质、全氮、全磷、全钾和速效钾效果最好.套种百喜草和狗牙根果园模式改良果园土壤全氮效果优于套种农作物模式.套种农作物模式改良果园土壤全磷效果、土壤碱解氮能力都明显好于套种不同牧草模式.套种百喜草和套种农作物提高果园土壤速效磷含量,而套种狗牙根与阔叶雀稗草则略为降低了土壤速效磷含量.与果园顺坡耕作套种相比,横坡套种具有更好的保持土壤养分的作用,适宜进一步推广.     

不同栽植密度对脱毒红薯产量及经济效益的影响

为确定三康8号脱毒红薯的最佳栽植密度并为其推广应用提供依据,采用大田试验方法,研究了不同栽植密度对脱毒红薯产量和经济效益的影响。结果表明:栽植密度为4 600株/667m2时,鲜薯产量高达2 577.9 kg/667m2,产投比高达2.37,是三康8号脱毒红薯的最佳栽植密度。     

冬季凌汛危害成因及防凌管理措施

通过分析冬季凌汛危害的成因,总结出防止凌汛的管理措施,对保证凌汛安全将起到很大的作用。     

Differences in ecological and allelopathic traits among Alternanthera philoxeroides populations

Based on a field investigation and laboratory trials, this study compared the invasive ecology of aquatic and terrestrial alligator weed (Alternanthera philoxeroides G.) ecotypes. The aquatic ecotype showed a stronger eco‐adaptation than the terrestrial ecotype. Alligator weed performed well in wetland and riparian habitats, where it was so competitive that only one‐to‐three other plant types grew successfully in its company. In contrast, it exhibited poor growth in upland fields and parks, where the terrestrial ecotype was dominated by 6–11 other alien plant species. The aquatic ecotype exhibited significantly greater growth inhibition of Microcystis aeruginosa. The ecotypes differed in their pattern of allelopathic inhibition of water blooms. The allelopathic effect of the aquatic ecotype persisted for a period exceeding 20 days, whereas the terrestrial ecotype's allelopathic effect subsided in <5 days. The aquatic ecotype had higher levels of antioxidant compounds, including soluble protein and flavones, and the activity of protective enzymes was also higher, which included superoxidase dismutase, peroxidase and catalase. Alligator weed's unique characteristics derive mainly from its strong allelopathic potential and tolerance of eutrophication in aquatic habitats.     

辽宁动漫游戏产业发展问题及对策研究

动漫产业被誉为21世纪最具发展潜力的朝阳产业之一。近年来,辽宁动漫产业发展迅猛,取得了巨大的成就。但对辽宁动漫产业发展现状进行分析后发现仍存在诸多问题。在世界经济格局重新调整的契机下,实施有效的发展战略是辽宁动漫游戏产业发展的根本保证。     

猕猴桃的后期管理

加强猕猴桃的后期管理 ,是提高果实品质 ,保证正常成熟的重要环节。1　改善光照条件8月中旬高温期过后 ,对二次副梢或三次副梢进行缩剪 ,若春梢摘心留叶数为 8片或 1 0片叶时 ,二次枝应在 3片至 5片叶处短截 ;有三次副梢出现的旺枝 ,将三次枝留 2片至 3片叶重剪或直接疏去。若春梢在 4片叶至 6片叶处缩剪 ,二次枝亦应在 4片至 6片叶处缩剪 ,将三次或四次副梢疏去。树势较旺者 ,对内膛细弱枝或自封顶枝 ,应适当中截着果节以上的枝段。行与行之间留足 80～ 1 0 0ｃｍ的间距 ,避免行间枝梢交叉。秋剪的主要对象是二次或三次 (四次 )副梢及其他…     

加强基层野生动物行政管理工作的探讨

概括总结基层野生动物行政管理的重要性,并就如何加强基层野生动物行政管理提出了五个方面的意见。     

Sequencing, Polymorphism and Expression Profile Analysis of Porcine Hexokinase Ⅱ (HK2) Gene

Hexokinase Ⅱ has been demonstrated to play the role of a key enzyme member in the glycolysis reaction. It catalyzes the conversion of glucose to glucose-6-phosphate, thus committing glucose to the glycolytic pathway. In this paper, the partial exons and introns 10, 11, 13 and 14 of the porcine HK2 gene were cloned and sequenced by comparative genomics.Comparative sequencing of three pig breeds revealed ten putative single-nucleotide polymorphisms (SNPs), one of which in intron 10 with differing bases (G981A) is within the restriction site for enzyme Msp Ⅰ. Distribution of Msp Ⅰ -RFLP genotype and allele frequencies among different pig breeds were studied. By association analysis between Msp Ⅰ PCR-RFLP polymorphism (AA, AB, BB genotypes of HK2 gene intron 10) and some meat quality and carcass traits in F2 group,which was constructed by our laboratory, a significant difference of pig average backfat at rump was found between AB and BB genotypes (P ＜ 0 05) in F2 group. In addition, the pattern of expression of HK2 in a variety of tissues in pig was also determined using semi-quantitative RT-PCR. The expression of HK2 mRNA was detected only in pig skeletal muscle.     

普那菊苣饲喂三元杂交猪的效果

利用普那菊苣青绿叶片配合精料育肥三元杂交肉猪,经过105 d的育肥,在5个不同搭配组合中,当青料干物质占日粮干物质的25.96%时,头日均增重最快,为692.12 g;瘦肉率较高,为63.78%,与对照差异达极显著(P＜0.01);屠宰率为74.06%,饲料转化率为3.02 kg,比对照低,但成本减少61.93元,效益增加60.19元;经济效益最高,为173.36元,与其他几个组合差异极显著(P＜0.01),是一个比较理想的搭配组合,可直接用于生产推广.