影响根癌农杆菌介导香蕉胚性悬浮细胞遗传转化的因素

用含质粒载体pCAMBIA1301的根癌农杆菌EHA105转化贡蕉(Musa A A Pisang Mas cv. Mas)品种的胚性悬浮细胞,通过测定GUS基因瞬时表达率,对转化初期的主要影响因素进行了研究。结果表明,取处于对数期的胚性悬浮细胞和D600nm为0.2的菌液混合,在室温、8000r/min离心5min,然后在110r/min的旋转摇床上摇5min,在体细胞胚诱导培养基上共培养8d,瞬时表达率达到最高值25.30%。     

绷紧巢框铁丝一简便法

平时绷紧巢框铁丝,有的巢框被铁丝嵌进孔的木质里,越拉越往里进,不易拉紧,久而久之孔越拉越大.笔者在给铁丝穿孔前,套上1个小垫圈,当拉紧铁丝时就被垫圈挡住,铁丝就进不到木质里去.     

Evaluation of polymerase chain reaction diagnosis of Cryptosporidium spp in dairy cattle and wildlife

This study investigated the utility of the polymerase chain reaction (PCR) protocol as a screening test for Cryptosporidium spp in 125 fecal samples from dairy cattle and wild rodents. Samples initially examined by fecal flotation and ELISA were evaluated using four PCR protocols (18S SSU rRNA, TRAP-C2, HSP70, and COWP), and the relative accuracy and agreement of PCR protocols was assessed. Although PCR can be both highly sensitive and accurate, the ability of these protocols to accurately detect DNA in samples can vary. A combination of techniques may be the best choice for to screen samples for this parasite.     

大蒜、辣椒、甘蓝宽厢、宽带高效立体种植模式

种植形式:采用225 cm为一带,宽带155 cm,窄带70 cm.于9月上旬开厢起垄,厢宽155 cm、垄高25 cm,窄带(沟宽)70 cm.9月中下旬在宽带种植8行大蒜,浇足清粪水并覆盖腐熟农家肥,达到保肥保水.同时在窄带种播幅为30 cm的旱地绿肥;翌年4月上旬把窄带绿肥压青起垄,垄宽60 cm,待绿肥腐熟后在垄面种植2行辣椒,采用地膜覆盖.大蒜收后在宽厢移栽5行结球甘蓝.     

中国小豆种质资源的收集与评价

截至１９９６年底收集的中国小豆种质有４０５３份,其中栽培３９９３份,野生种６０份,地方农家品种占栽培种的９７．４％,主要分布在我国华北和中部生态区,１９８６～１９９５年间对这些资源进行农艺性状和特性鉴定评价,筛选出一批矮秆,直立,早熟,大粒,种子高蛋白,高淀粉含量,抗旱,抗寒,耐盐和抗病虫的种质。     

Dietary fatty acids and inflammation in the vertebral column of Atlantic salmon, Salmo salar L., smolts: a possible link to spinal deformities

Vegetable oils (Vo) are an alternative to fish oil (Fo) in aquaculture feeds. This study aimed to evaluate the effect of dietary soybean oil (Vo diet), rich in linoleic acid, and of dietary fish oil (Fo diet) on the development of spinal deformities under bacterial lipopolysaccharide (LPS)‐induced chronic inflammation conditions in Atlantic salmon, Salmo salar L. Fish [25 g body weight (BW)] were fed the experimental diets for 99 days. On day 47 of feeding (40 g BW), fish were subjected to four experimental regimes: (i) intramuscular injections with LPS, (ii) sham‐injected phosphate‐buffered saline (PBS), (iii) intraperitoneally injected commercial oil adjuvant vaccine, or (iv) no treatment. The fish continued under a common feeding regime in sea water for 165 more days. Body weight was temporarily higher in the Vo group than in the Fo group prior to immunization and was also affected by the type of immunization. At the end of the trial, no differences were seen between the dietary groups. The overall prevalence of spinal deformities was approximately 14% at the end of the experiment. The Vo diet affected vertebral shape but did not induce spinal deformities. In groups injected with LPS and PBS, spinal deformities ranged between 21% and 38%, diet independent. Deformed vertebrae were located at or in proximity to the injection point. Assessment of inflammatory markers revealed high levels of plasma prostaglandin E₂ (PGE₂) in the Vo‐fed and LPS‐injected groups, suggesting an inflammatory response to LPS. Cyclooxigenase 2 (COX‐2) mRNA expression in bone was higher in fish fed Fo compared to Vo‐fed fish. Gene expression of immunoglobulin M (IgM) was up‐regulated in bone of all LPS‐injected groups irrespective of dietary oil. In conclusion, the study suggests that Vo is not a risk factor for the development of inflammation‐related spinal deformities. At the same time, we found evidence that localized injection‐related processes could trigger the development of vertebral body malformations.     

水肥供应对南疆沙区滴灌红枣生理、生长及产量的影响

为了了解南疆沙区水肥供应对滴灌红枣生理、生长指标与产量的影响,以当地8 a成龄骏枣树为供试材料,结合大田试验,在滴灌条件下进行水肥二因素三水平完全处理小区试验。结果表明:灌水因素对红枣叶片光合特性(净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、细胞间隙CO_2浓度(Ci)、水分利用效率(WUE))、红枣梢径和梢长增加量及灌溉水分利用效率(iWUE)达到显著(P0.05)或极显著水平(P0.01),水肥交互作用对红枣光合特性、梢径和梢长增加量、产量及灌溉水分利用效率(iWUE)达到显著(P0.05)或极显著水平(P0.01),施肥对红枣以上指标未达到显著性水平(P0.05);过高或过低的灌水量均不利于红枣光合作用、生长发育及增产效果,较低的施肥量可以促进红枣生理生长、达到红枣增产的目的;W2F1处理下红枣叶片Pn(8.94μmol·m~(-2)·s~(-1))、Tr(3.86 mmol·m~(-2)·s~(-1))、Gs(0.49μmol·m~(-2)·s~(-1))和Ci(707.41μmol·m~(-2)·s~(-1))值最大,比最小值分别提高23.00%、22.54%、58.06%和58.08%;W3F3处理下WUE值(2.56μmol·mmol-1)最大;梢径增加量和梢长增加量最大值分别在W2F2处理(6.31 mm)、W3F2处理(64 cm),比最小值分别提高51.32%、33.33%;W2F1处理下产量(7 256 kg·hm~(-2))最大,比最小值处理增产55.67%,增产效应(33.14%)最大;iWUE最大值在W1F3处理(8.17 kg·m~(-3)),与W2F1处理无显著性差异(P0.05)。红枣净光合速率与蒸腾速率、气孔导度之间密切相关,红枣产量与红枣梢径增加量有较好的相关关系,梢径增加量在一定程度上能反应红枣产量。灌水量820 mm、施肥量N-P_2O_5-K_2O:200-100-150 kg·hm~(-2)(W2F1处理)为南疆沙区节水、节肥的最佳水肥供应模式。     

ANSYS在木结构构件中的应用

介绍了大型通用有限元软件ANSYS的特点和进行有限元分析的一般步骤。通过在木桁架、木结构剪力墙和木结构楼板3种结构中应用得知,ANSYS可以用于对木结构构件的建模和应力分析以及进行相应的力学性能预测,且研究精度高、速度快,可节约大量的产品试制和试验经费,同时还可以实现对结构的优化。     

五峰县农业环境污染现状与综合治理对策

五峰是一个农业县,具有得天独厚的自然生态环境和丰富的农作物资源。虽然经过近30年的发展,摆脱了农产品短缺的长期困扰,但随着农业集约化、专业化和区域化程度的不断提高及养殖业的快速发展,化肥、农药、农膜、畜禽粪便及污水等农业投入和农业副产品大量流失进入各类环境介质,造成的农业环境污染问题越来越突出,严重影响农业生产安全及农产品质量安全。因此,科学合理使用农业投入品,综合防治农业环境污染,全面提升农产品产地环境质量,确保农业生产安全是各级政府、部门亟待解决的问题。