耕作与施肥模式对渭北旱塬春玉米田蓄水保墒与玉米产量的影响

为揭示渭北旱塬春玉米田休闲期不同保护性耕作模式的蓄水保墒与增产增收效应,寻找适合渭北旱塬春玉米田水肥高效利用的耕作方式和施肥水平,于2013—2014年度在陕西省合阳县甘井镇春玉米田分别设置传统农户模式(翻耕+低肥,S1)、现有高效模式(免耕+高肥,S2)、创新高效模式(深松+平衡施肥,S3)等模式处理,研究各类耕作与施肥相结合保护性耕作模式下春玉米水分利用率、产量和经济效益差异。结果表明,创新模式S3和现有模式S2较农户模式S1播前增加了土壤贮水量;创新模式S3和现有模式S2处理在玉米主要生育期0~200 cm土层平均土壤贮水量分别比农户模式S1增加23.3 mm和18.1 mm,水分利用效率分别提高12.3%和10%,产量增加11.1%、9.2%。创新模式和现有模式均较农户模式能够增加土壤贮水量,提高水分利用效率,增加产量和经济效益,但创新模式蓄水保墒,增产增收优势明显,是适合渭北旱塬地区春玉米生产的水肥管理模式。     

Effects of nitrogen and water stress on the rehydration,endogenous hormonal regulation and yield of maize

Water scarcity is known to be a strong limiting factor affecting maize grown and yield in cold semi-arid regions. Numerous studies have shown that rehydration improves maize growth. Our study aimed to explore the effects of rehydration treatments on maize growth and yield under water and nitrogen stress during different growth stages. We selected the drought-tolerant maize variety Nendan 19 (ND19) and subjected it to water stress during the V6 (sixth-leaf), R2 (filling) and R6 (maturity) growth stages and a rehydration treatment after each stress stage. Our results indicated that N1 (N100 kg N ha⁻¹) and N3 (N300 kg N ha⁻¹) treatments significantly increased the leaf moisture status relative to water content (RWC), bound water content (BWC), free water content (FWC) and water potential (WP)) at different growth stages. Similar trends were observed in the accumulation of plant leaf and root hormones (zeatin+zeatin riboside, indole-3-acetic acid, abscisic acid and gibberellic acid), photosynthetic pigments and chlorophyll fluorescence. However, under the same water stress conditions, they decreased as the N rate increased and reached a minimum value in the S3 (water stress for N3) treatments. In addition, with growth stage advancement and extension of the rehydration time, both showed a gradual upward trend. The results showed that to save water resources in the cold semi-arid region, rehydration treatments (R2S1 and R2S3) significantly increased the photosynthetic pigments and chlorophyll fluorescence parameters, leaf moisture status, biomass, 100-grain weight, hormone content, ear characteristics and grain yield of maize.     

In UV‐B Irradiated Rice High Levels of Mn Limits Chloroplasts Injury Triggered by Oxidative Stress

The molecular mechanism to control the oxidative burst exerted by Mn accumulation in rice (Oryza sativa L.) plants, grown in hydroponics containing 0.5, 2 and 8 mg l^–1 Mn and irradiated with a total biological effective UV‐B irradiation of 20.825 kJ m^?2, was investigated in the chloroplasts at the 15th and 21st days after germination. In both experimental periods, Mn accumulation kinetics in the leaves and in the chloroplast lamellae displayed overall increases. Coupled to higher membrane selectivity, superoxide production and acyl lipids peroxidation in the thylakoids decreased, prompting upper rates of the Hill and Mehler reactions. Connected to UV‐B irradiation, higher accumulated Mn in thylakoids was found to be chelated in a 36.5 kDa protein, with Mn/protein ratio of about 1 and high content of Gln, Asp, Glu, Leu and Gly, being its EPR spectrum characteristic of high‐spin Mn(II), in a S = 5/2 ground state. As this protein exhibited enzymatic catalysis of superoxide dismutation, it was concluded that, under UV‐B irradiation, the high internal tolerance of Oryza sativa L. to Mn during the vegetative growth also triggers the synthesis of a manganese protein that mimics superoxide dismutase functioning, therefore furnishing an additional intimate protection against oxidative stress.     

黑麦草叶蛋白提取工艺研究

采用酸化和加热相结合的方法，研究了从黑麦草中提取叶蛋白的最佳工艺条件，并分析了黑麦草叶蛋白中的氨基酸组成。结果表明黑麦草叶蛋白提取的最佳工艺条件为pH4.0，料水比1：2，凝聚温度为70℃，加热时间5min。该条件下提取的叶蛋白含量可高达70.48%。氨基酸分析显示黑麦草叶蛋白中人体必需氨基酸、鲜味氨基酸和药效氨基酸分别占总氨基酸的40.3247%、22.2439%和77.5609%。黑麦草叶蛋白具有很好的营养、保健和药用价值。     

Effects of Energy,Protein and Amino Acids Levels on the Development of Mammary Gland and the Growth of Fetus in Sows at Late Gestation

Late gestation is an important period for rapid development of the sow's mammary gland and fetus. It is becoming more and more important to provide a suitable nutrient level in late gestation period for improve the reproductive efficiency of sow. Demand of energy, protein and amino acids for mammary gland and fetus in sows at late gestation are different. To provide reasonable nutrition for fetus, at the same time for the needs of mammary gland are still seldom reported. In this paper, the effects of dietary energy, protein and amino acids levels on the development of mammary gland and the growth of fetus were reviewed,the authors propose the requirement of energy, protein amino acid and reasonable proportion in sows at late gestation, in order to give some guidance for pig farmers.     

根据个体间蛋白质多位点基因型的比较分析中国黄牛的遗传关系

现行群体间遗传距离的度量方法都以等位基因频率的计算为依据，这些方法的缺点之一是在位点不多，多态笥不高时要求群体有较大的取样个体数目，另外，这些方法所建造的树素图不能反映群体是由混血引起还是由长期进化引起这一问题，针对这些问题，本文提出了以个体间蛋白质多位点基因型比较为基础的群体间遗传距离和群体内基因杂合度的度量方法，以十个主要中国黄牛群体的遗传关系分析为例，比较圆满的解决了上面几个问题。     

Metabolism of microbial nitrogen in ruminants with special reference to nucleic acids

Characteristically the metabolism of microbial nitrogen (N) compounds in ruminants involves the degradation of dietary N and synthesis of microbial protein (MP), compounds including a small amount of peptides and free amino acids, which may account for 75–85% of total N and the remainder are nucleic acids (NA: DNA and RNA). Generally rumen microbes contain 10–25% NA‐N of the total N while 70–80% is in the form of RNA. This paper describes the degradation and synthesis of NA in the rumen and their fate in the lower digestive tracts. Their physiological and nutritional significance in different types of ruminant animals is also discussed. The research works on NA metabolism in ruminants has been mainly on metabolism of purines after rumen microbial digestion and absorption in the lower gut. Subsequently, the fate of absorbed purines has been intensively investigated to assess the extent of MP synthesis in the rumen. The method for predicting ruminal synthesized MP and subsequently digested MP has been proposed using urinary purine derivative (PD) excretion in sheep and cattle fed on ordinary feed. The latter approach has now been adopted for calculation of protein supply in some feeding standards, although there are still difficulties in predicting representative samples of rumen microbes, and also uncertainties in variations of non‐renal and endogenous purine losses.     

用重组核衣壳蛋白ELISA检测PRRSV抗体的研究

ＰＲＲＳＶ重组Ｎ蛋白ＥＬＩＳＡ检测人工感染猪血清７５份,与ＩＤＥＸＸ公司ＥＬＩＳＡ试剂盒及ＩＦＡ的符合率分别为９７．３％和１００％。检测疫苗免疫猪血清,阳性率１００％。在免疫后６ｄ就能检出抗体,比ＩＦＡ敏感。检测８５份我国田间猪血清,阳性率１８．８％。     

Effects of Supplementing a Basal Diet of Chloris gayana Hay with One of Three Protein-rich Legume Hays of Cassia rotundifolia,Lablab purpureus and Macroptilium atropurpureum Forage on Some Nutritional Parameters in Goats

Growth and digestibility experiments were conducted on growing East African type goats offered Chloris gayana hay supplemented with one of three high-protein (119–128 g CP/kg DM) legume hays, Cassia rotundifolia (cassia), Lablab purpureus (lablab) or Macroptilium atropurpureum (siratro), and crushed maize to investigate the feed intake, digestibility, growth and urinary excretion of purine derivatives. Goats in the supplemented groups had higher total dry matter and nitrogen intakes and higher N retention and body mass gains than unsupplemented counterparts. The digestibility of dry matter, organic matter and neutral detergent fibre were increased by protein supplementation. Animals on supplemented diets had higher fractional outflow rates of particulate matter from the rumen. The production of protein by ruminal microbes and the efficiency of microbial N production were increased by supplementation. It was concluded that a mixture of low-quality grass hay (61.9 CP/kg DM) and either cassia, lablab or siratro hay, and maize grain can provide a productive balanced diet for growing goats.