油菜冻害原因及其预防措施

对油菜冻害发生的症状、原因进行了分析,并提出了相应的预防措施。     

Immune responses in piglets infected with highly pathogenic porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) infection compromises the host's innate and adaptive immunity. The aim of this study was to investigate the immune responses of piglets infected with highly pathogenic (HP) PRRSV (HuN4 strain) with or without the immunization with CH-1R attenuated PRRSV vaccine. The response was evaluated for the clinical signs, pathological changes and virus load in immune organs, antibody responses and levels of serum IFN-γ, IL-4 and IL-10. The result showed that in comparison with the piglets received the immunization, the piglets infected with HP-PRRSV alone had the thymus atrophy, decreased serum levels of IL-4 and increased serum levels of IL-10 and INF-γ. These results suggest that elevated IL-10 levels at the early stage of the infection may enhance virus survival and delay the induction of protective immunity, while increased levels of IL-4 induce the effective immune responses and increase the animals' health status.     

A molecular marker linked to the Prv1 gene that confers resistance to Papaya ringspot virus-type W in melon

Papaya ringspot virus‐type W (PRSV‐W) is the most prevalent and important viral pathogen of cucurbits in Brazil. It can be effectively controlled by the incorporation of genetic resistance into susceptible melon cultivars. The present study identified amplified fragment length polymorphic (AFLP) markers linked to the PRSV‐W resistance Prv¹ allele. The susceptible yellow‐fleshed melon‐breeding line AF426^prv1 and its nearly isogenic‐resistant line AF426^Prv1, which carries the Prv¹ allele resident in the Indian cantaloupe U.S. Plant Introduction (PI) 180280, were screened for AFLP marker polymorphisms. Of 30 251 AFLP loci, only three were polymorphic between the nearly isogenic lines. Segregation analyses for these three polymorphic markers and the Prv¹ allele using a BC₁ population of 197 plants indicated close linkage (0.5% recombination frequency) between marker EK190 (HindIII‐CGA and MseI‐GTG; 190 bp) and Prv¹. Thus, EK190 might be a useful marker in breeding programmes aiming to develop melon cultivars resistant to PRSV‐W. The other two markers are closely linked to each other, but distantly linked to Prv¹.     

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.     

深刻领会"三个代表"重要思想努力做好新形势下的工会工作

江总书记“三个代表”的重要论述 ,对于做好新形势下工会工作 ,具有重要的指导意义。本文紧密结合工会工作 ,从政治指导方向、物质文明建设、精神文明建设以及维护广大职工利益等方面作了阐述。     

草莓快速繁殖技术的研究

本文探讨了利用茎尖离体培养法进行草莓快速繁殖的方法。主要摸索了激素对试管苗的分化、生根的影响及移栽成活的技术要点。     

Both TGF-β1 and Smad4 regulate type I collagen expression in the muscle of grass carp,Ctenopharyngodon idella

Fish Physiology and Biochemistry - Type I collagen is proven to make an important contribution to fish muscle quality. Our previous study has shown the Smad4-dependent regulation of type I collagen...