‘神马’切花菊蕾期采后催花液

以蔗糖(质量浓度分别为30、40、50 g.L-1)、8-羟基喹啉(质量浓度分别为100、200、300 mg.L-1)、水杨酸(质量浓度分别为75、100、150 mg.L-1)、氯化钙(质量浓度分别为150、200、250 mg.L-1)为催花液4因素,采用4因素3水平正交试验设计,通过瓶插催花试验筛选出‘神马’切花菊蕾期采后最佳催花液组合及主效因素。通过进一步验证试验,验证最佳催花液。结果表明:正交试验得到‘神马’切花菊蕾期采后最佳催花液为50 g.L-1蔗糖+300 mg.L-18-羟基喹啉+75 mg.L-1水杨酸+150 mg.L-1氯化钙,主效因素为蔗糖。在验证试验中,最佳催花液处理与对照相比差异极显著,能够在3 d内催开花蕾,使切花比露地早半个月开花,并使其整体达到催开标准;提高花枝的水分吸收能力及花瓣中可溶性蛋白和可溶性糖的质量分数,其中蛋白质质量分数最高可达到7.125 mg.g-1,可溶性糖质量分数最高可达到0.042 6 mg.g-1,均高于对照及其他处理的最高值;花瓣中POD酶活性增强,SOD酶活性相对平稳。     

植物化学诱导表达系统的类型和应用研究

介绍了植物化学诱导表达系统的构建原理,列举了该表达系统的类型,并展望了其应用前景。     

Can outdoor rearing and increased weaning age compensate for the removal of in-feed antibiotic growth promoters and zinc oxide?

This experiment determined whether delayed weaning and outdoor rearing could compensate for the removal of antimicrobials from piglet diets. One hundred and sixty litters of Large White (75%) × Landrace (25%) pigs on the same unit were reared either indoors (In) or outdoors (Out) and weaned at either 4 or 6 weeks of age into flat deck accommodation onto diets supplemented with either no antibiotic growth promoters and no zinc oxide (Un) or 40 mg avilamycin and 3.1 g zinc oxide/kg diet (S). Piglet performance was monitored to 8 weeks of age. A proportion of litters (25%) were sampled to investigate the effect of the different treatments on gut development. Mortality was higher in the first 24 h of life for Out piglets which subsequently grew faster to weaning. This was not simply due to smaller litter size as total litter gain was higher in outdoor litters. All piglets responded positively to antimicrobial supplementation post weaning regardless of rearing environment and weaning age and this was the biggest influence on post weaning performance. Outdoor piglets grew faster than indoor piglets post weaning (295 versus 242 ± 8.6 g/pig/day for the first 2 weeks post weaning, P < 0.001) and over the same period 6 week weaned piglets grew faster than 4 week weaned (324 versus 213 ± 8.6 g/pig/day, P < 0.001), however, when compared at similar age, 6 week weaning was detrimental to piglet growth with average daily gain (adg) from 4 to 8 weeks of age 310 g/pig/day versus 329 for 4 week weaned piglets (P = 0.001). At 8 weeks of age the outdoor 6 week weaned unsupplemented piglets had similar average weight to the indoor 4 week weaned supplemented piglets indicating the potential of this combination to counteract the need for antimicrobials, however the benefit was due to enhanced weaning weight not to improved post weaning performance.     

Regulation of tissue beta-adrenergic, glucocorticoid and androgen receptors induced by repeated exposure to growth promoters in male veal calves

Biochemical modifications induced by a combination of anabolic compounds in target organs of male veal calves have been evaluated. Six male Friesian crossbred calves were treated with of 17beta-estradiol, dexamethasone sodium phosphate and clenbuterol or served as controls. beta-Adrenoceptors (beta-ARs) were measured in myocardium, lung, spleen, cerebral cortex, hippocampus, thalamus, hypothalamus, and hypophysis, glucocorticoid receptors (GRs) in the spleen and androgen receptors (AnRs) in the testis, by binding assay. A significant decrease in beta-ARs was observed in all tissue samples from treated animals. In the spleen the two GR subtypes found, low (LA) and high (HA) affinity GRs, were down-regulated by the treatment. A significant (P<0.05) decrease of testis weight and a significant (P<0.05) up-regulation of AnRs was also observed. Our data demonstrate that long-term treatment with anabolic compounds markedly affects receptor concentrations in target organs of male veal calves. Thus, studies investigating biological assays as screening methods to detect such compounds should be encouraged.     

Actinobacteria-enhanced plant growth, nutrient acquisition, and crop protection: Advances in soil, plant, and microbial multifactorial interactions

Agricultural areas of land are deteriorating every day owing to population increase, rapid urbanization, and industrialization. To feed today’s huge populations, increased crop production is required from smaller areas, which warrants the continuous application of high doses of inorganic fertilizers to agricultural land. These cause damage to soil health and, therefore, nutrient imbalance conditions in arable soils. Under these conditions, the benefits of microbial inoculants (such as Actinobacteria) as replacements for harmful chemicals and promoting ecofriendly sustainable farming practices have been made clear through recent technological advances. There are multifunctional traits involved in the production of different types of bioactive compounds responsible for plant growth promotion, and the biocontrol of phytopathogens has reduced the use of chemical fertilizers and pesticides. There are some well-known groups of nitrogen-fixing Actinobacteria, such as Frankia, which undergo mutualism with plants and offer enhanced symbiotic trade-offs.In addition to nitrogen fixation, increasing availability of major plant nutrients in soil due to the solubilization of immobilized forms of phosphorus and potassium compounds, production of phytohormones, such as indole-3-acetic acid, indole-3-pyruvic acid, gibberellins, and cytokinins, improving organic matter decomposition by releasing cellulases, xylanase, glucanases, lipases, and proteases, and suppression of soil-borne pathogens by the production of siderophores, ammonia, hydrogen cyanide, and chitinase are important features of Actinobacteria useful for combating biotic and abiotic stresses in plants.The positive influence of Actinobacteria on soil fertility and plant health has motivated us to compile this review of important findings associated with sustaining plant productivity in the long run.     

香菇gpd启动子引导的云芝漆酶基因真核表达载体的构建

根据Genbank中提交的云芝(Coriolus versicolor (L.) Quel.)漆酶(lcc1)基因cDNA序列设计引物,利用RT-PCR获得云芝漆酶基因cDNA完整编码框,与GenBank中云芝漆酶基因同源性为96%;以pCAMBIA1381xb为初始载体,利用引物两端的酶切位点,将克隆得到的云芝漆酶基因cDNA序列分别连接到香菇gpd启动子Lg1和Lg2的下游,构建成香菇启动子引导的云芝漆酶基因真核表达载体pC-XG1-YZ-Lac和pC-XG2-YZ-Lac,利用冻融法将其转到了农杆菌EHA105中.     

种子特异启动子的克隆及植物表达载体构建

[目的]启动子是植物基因工程中一个重要工具,对构建植物生物反应器有着重要意义。8S球蛋白是绿豆中含量最丰富的种子贮藏蛋白,因此,其调控序列可能提供了一个很好来源的种子特异性启动子。[方法]通过基因组步移技术克隆了绿豆8s球蛋白a亚基基因8SGα的启动子区域,基因组步移使用的引物根据绿豆8SGα的cDNA序列设计。[结果]通过3轮PCR的扩增,得到了472bp的上游序列片段,构建了植物双元表达载体pBI－8SGα-GUS。[结论]研究结果可用于转化植物,并于转基因植物中分析启动表达的时空特异性及表达强度,并为植物种子生物反应器提供重要元件。     

The long-term approach to parasitic weeds control: manipulation of specific developmental mechanisms of the parasite

Parasitic weeds pose a tremendous threat to world agriculture, mainly because they are at present almost uncontrollable. The root parasites Striga (witchweed) and Orobanche (broomrape) are vicious pests in both tropical and sub-tropical areas. A thorough understanding of their biology, including detailed knowledge of the specific mechanisms of parasitism, is needed in order to develop novel control methods. Some main developmental steps are described for the root parasites: seed conditioning and germination, haustorium formation, penetration into host tissues, maturation of the haustorium, and seed production. All these stages can be targeted in order to achieve parasite control. For example, based on our findings regarding gibberellin synthesized during seed conditioning, we were able to prevent parasitism by soil application of an inhibitor of gibberellin synthesis. Other developmental stages, such as germination stimulation, the enzymatic penetration of the haustorium into host tissues, and the source–sink relations between host and parasite are also possible targets for control, and the mechanisms involved may be manipulated for specific control of the parasites.