冬小麦休耕对土壤动物群落及其摄食活性的影响

为明确农田土壤动物对不同耕作制度的响应,本研究以华北小麦田土壤微节肢动物为研究对象,探究休耕对土壤微节肢动物群落及其摄食活性的影响。试验设置不播种作物的样方作为休耕处理,正常播种作为不休耕处理,分析处理间和不同土层的土壤温湿度时空差异,并利用诱饵薄条法（Bait-Lamina Test,BLT）原位解析土壤动物的摄食活性。结果表明：休耕与不休耕处理中的土壤微节肢动物均以真螨目为优势类群,其占总丰度的89%,并且具有明显的表聚效应。此外,休耕对不同土层深度土壤微节肢动物群落的影响不一致,0～5 cm土层、不休耕处理中的土壤微节肢动物丰度显著增加,约为休耕处理的4.4倍;5～10 cm土层、不休耕处理的微节肢动物数量相较于休耕处理增长了约46%。相关性分析显示,土壤微节肢动物摄食活性与土壤温湿度和不同种植模式均存在显著正相关关系。从小麦的拔节期到成熟期,休耕处理中土壤微节肢动物的摄食活性均显著高于不休耕处理,且在土壤湿度最高的抽穗期达到最大。研究表明,休耕显著降低了0～10 cm深度土壤微节肢动物的数量和多样性,但提高了其摄食活性,土壤微节肢动物群落的摄食活性主要受土壤湿度的影响。     

绿豆系列新品种选育

自1985年来,利用系统选育与杂交育种相结合,选育出了高产、优质、极早熟、抗逆性强、适应范围广、各具特点的绿豆系列新品种鲁绿1号、潍绿1号、潍绿4号:在省区试和生产试验中均比对照增产30%以上;蛋白质含量27.7%~27.9%;夏播生育期60~67d;成功地解决了高产、优质、早熟之间的矛盾;实现了山东省绿豆品种的更新换代。     

黄泛沙地林农间作土壤的物理性质改良及碳固持特征

[目的]探究白蜡林不同林农间作模式对黄泛沙地土壤物理性质改良尤其是碳固持的影响,为区域未来林农间作模式优化提供科学指导。[方法]以山东省菏泽市黄泛沙地国有东明林场白蜡—菊花、白蜡—花生、白蜡—大豆3种典型林农间作模式为研究对象,以白蜡纯林为对照,采用野外采样与室内测试相结合的方法,分析不同模式的土壤物理性质及碳固持特征。[结果](1)0—20 cm的土壤容重差异显著,呈现白蜡纯林>白蜡—花生间作>白蜡—菊花间作>白蜡—大豆间作的趋势,白蜡—大豆间作模式可明显降低0—20 cm层土壤容重(较其他模式降低7.4%～13.2%),提高土壤总孔隙度(提高2.3%～19.8%),改良土壤结构;(2)白蜡—大豆间作模式土壤固碳能力最强,比纯林高14.54 t/hm²,且随土层深度增加表现越明显,更有益于增强土壤肥力,进而提高土壤质量。[结论]在碳中和的模式下,白蜡—大豆间作模式应是黄泛沙地农林经营管理的重点,在提高区域生态效益的同时,可进一步促进农林业绿色发展。     

Reclamation of desert land to continuous cotton cropping affects soil properties and microbial communities in the desert-oasis ecotone of Xinjiang,China

Purpose

A large area of desert land in the desert-oasis ecotone in northwestern China is being reclaimed for continuous cotton production for several decades. However, little is known about the possible effect of reclamation and long-term monocultural cotton cultivation on soil properties and microbial communities in the desert-oasis ecotone area.

Materials and methods

Soil samples were collected from the 0–20-cm mineral soil from croplands that had been continuously planted cotton for 5, 25, and 50 years after reclamation, as well as a desert land (t?=?0, before reclamation, used as the control). Soil physical and chemical properties, enzyme activities, and bacterial and fungal community diversities were determined.

Results and discussion

Soil organic carbon, total nitrogen, and enzyme activities increased up to 25 years after reclamation, and further monocultural cotton cropping was not beneficial to improve soil quality. Soil urease, alkaline phosphatase, and sucrase activities increased by 121~205%, 100~167%, and 206~719% in croplands as compared with the desert land, respectively, after reclamation with the highest value at 25 years of cotton cultivation. Bacterial richness and diversity increased from desert land to the 5-year-old cropland and then remained stable after 5 years of cotton cropping, and soil fungal richness and diversity were not affected by reclamation and cropping years.

Conclusions

Crop rotation or fallow should be considered to maintain or improve soil quality over the long-term monocultural cropping.

     

猪屎豆丛枝病植原体的分子检测与鉴定

植原体(phytoplasma),原称类菌原体(MLO),在植物和昆虫中广泛分布,为无细胞壁原核微生物,尚不能在人工培养基上离体培养.迄今,世界各地已统计有1000多种植物自然感染植原体病害(Seemüller et al.,1998),我国也报道了100多种植物植原体病害(赖帆等,2008).     

Development and Preliminary Application of Apd-ELISA Kit for Antibody Detection of Haemophilus parasuis

The present study aimed to develop an ELISA for detecting antibodies of Haemophilus parasuis by optimization of reaction conditions, determination of its cutoff value and evaluation of its application with autotransporter passenger domain (Apd) as the coating antigen. Firstly, the porcine sera from immunization and challenge experiments were used as HPS-positive and -negative control sera to optimize the Apd-ELISA reaction parameters and conditions. Next, the cutoff value was determined based on testing of the serum samples with confirmed background, and then the blocking solutions and the packing methods of plates were selected. Finally, Apd-ELISA was used to detect clinical serum samples and then compared with the Biocheck OppA-ELISA kit from Netherland. With the coating antigen at 0.5 μg·mL^-1, the tested sera being diluted at 1:200 and incubation for 45 min and HRP-labeled goat anti-pig second antibody being diluted at 1:15 000, Apd-ELISA displayed the improved discriminative capability and the reduced background signal. The cutoff value was determined to be 0.33 by calculation formula (S-N)/(P-N) and the OD_{630 nm} value of the 27 positive porcine sera and 40 negative porcine sera with the confirmed background. The blocking solution K and the vaccum package can preserve ELISA plates for 4 days at 50 ℃ (comparable to 22 months at 4 ℃). Detection of 1 179 clinical sera with Apd-ELISA indicated that the positive rates were 83.76%, 61.09% and 27.48% in sows, fattening pigs and piglets, respectively. Compared with the OppA-ELISA kit from Biocheck (OppA-ELISA), Apd-ELISA showed 100% identity to the results of OppA-ELISA kit in clinically negative sera and experimentally positive sera from the pigs immunized with the inactivated vaccine, but 4.76%(6/126)identity to the results in the sera from clinically positive sera. However, Apd-ELISA displayed 73.02%(92/126)identity to the results of OppA-Western blot in the sera from clinically and experimentally infected pigs. The present study obtained the Apd-ELISA kit that can effectively distinguish HPS-positive and -negative sera and can be stably preserved, which would be applied for antibody monitoring among pigs immunized with HPS-inactivated vaccine and subjected to infection of H. parasuis.     

农业专家系统的发展趋势

农业专家系统主要具有7个方面的发展趋势,尤其是与网络技术的充分融合及其开发工具的研发。     

绞股蓝皂苷生物合成后修饰酶基因的cDNA克隆和组织表达特征

从绞股蓝转录组挖掘可能与绞股蓝皂苷生物合成相关修饰酶基因细胞色素P450(cytochrome P450,CYP)及UDP-糖基转移酶(UDP-dependent glycosyltransferase,UGT)基因的cDNA进行克隆并开展了以下研究。根据课题组前期绞股蓝转录组数据,筛选CYP及UGT Unigenes,利用RT-PCR克隆ORF全长,并结合生物信息学对其编码蛋白进行功能分析,最后通过荧光定量PCR验证其在根、茎、叶的差异性表达。结果克隆得到两个ORF序列,分别命名为CYP94A1和UGT91A1;CYP94A1序列包含1509 bp的开放阅读框架,编码一条含503个氨基酸残基的肽链,具有CYP保守结构域;UGT91A1序列包含1383 bp的开放阅读框架,编码一条含461个氨基酸残基的肽链,具有UGT保守结构域。这两个基因的转录表达均具有组织特异性,在叶或茎中的表达均高于根。CYP94A1和UGT91A1的克隆、转录表达及生物信息学分析为进一步挖掘绞股蓝中CYPs、UGTs及功能验证提供了帮助,增加对CYP和UGT两个超基因家族的认识。     

绿豆系列新品种选育研究

自1985年来,利用系统选育与杂交育种相结合,选育出了高产、优质、极早熟、抗逆性强、适应范围广、各具特点的绿豆系列新品种鲁绿1号、潍绿1号、潍绿4号:在省区试和生产试验中均比对照增产30%以上;蛋白质含量27.7%~27.9%;夏播生育期60~67d;成功地解决了高产、优质、早熟之间的矛盾;实现了山东省绿豆品种的更新换代。     

香蕉粉喷雾干燥工艺优化

为了改善香蕉粉的喷雾干燥效果,优化喷雾干燥工艺,该文研究了进风温度、助干剂添加量、热空气流量、压缩空气流量的变化对香蕉汁喷雾干燥效果的影响,并采用Box-Behnken响应曲面法优化喷雾干燥条件,分析进风温度、热空气流量、压缩空气流量的变化对出风温度和产品得率的影响规律。结果显示：当进风温度为170.0℃、热空气流量为36.08 m3/h、压缩空气流量为489.70 L/h时,出风温度为76～80℃,产品得率最高,达44.28%,所制备的香蕉粉含水率低于5%,符合固体饮料标准。由此说明,通过响应曲面优化得到的喷雾干燥工艺能有效应用于加工香蕉粉。