罗汉果种子传播小西葫芦黄化花叶病毒的检测

为了解小西葫芦黄化花叶病毒（Zucchini yellow mosaicvirus,ZYMV）是否能通过罗汉果种子传播。本研究通过取ZYMV阳性的罹病罗汉果植株种子700粒,400粒直接播种于防虫网室中,300粒经表面消毒处理后播种于MS培养基上。最终获得213棵罗汉果实生苗。对所获得实生苗进行生物学鉴定及ZYMV特异性RT-PCR检测,均未检测到ZYMV阳性植株。结果表明ZYMV不能经罗汉果种子传播,或其传播率很低。     

Enzymatically catalyzed synthesis of low-calorie structured lipid in a solvent-free system: optimization by response surface methodology

A kind of low-calorie structured lipid (LCSL) was obtained by interesterification of tributyrin (TB) and methyl stearate (St-ME), catalyzed by a commercially immobilized 1,3-specific lipase, Lipozyme RM IM from Rhizomucor miehei . The condition optimization of the process was conducted by using response surface methodology (RSM). The optimal conditions for highest conversion of St-ME and lowest content LLL-TAG (SSS and SSP; S, stearic acid; P, palmitic acid) were determined to be a reaction time 6.52 h, a substrate molar ratio (St-ME:TB) of 1.77:1, and an enzyme amount of 10.34% at a reaction temperature of 65 °C; under these conditions, the actually measured conversion of St-ME and content of LLL-TAG were 78.47 and 4.89% respectively, in good agreement with predicted values. The target product under optimal conditions after short-range molecular distillation showed solid fat content (SFC) values similar to those of cocoa butter substitutes (CBS), cocoa butter equivalent (CBE), and cocoa butters (CB), indicating its application for inclusion with other fats as cocoa butter substitutes.     

商陆不同极性、根和茎提取物的抑菌性能分析

为探究商陆不同极性、部位提取物的抑菌性能,本实验分别从商陆根和茎中提取石油醚相、乙酸乙酯相、正丁醇相和水相4种不同极性的提取物,再采用滤纸片法测量提取物对大肠杆菌（Escherichia coli）、金黄色葡萄球菌（Staphyloccocus aureus）、巨大芽孢杆菌（Bacillus megaterium）和副溶血弧菌（Vibrio parahaemolyt-icus）4种细菌的抑制性能。结果表明,部分商陆的提取物有一定的抑菌活性,如根正丁醇相对巨大芽孢杆菌和副溶血弧菌,茎水相对副溶血弧菌的抑菌圈在10mm以上,但总体上商陆的提取物的抑菌性能远不及头孢氨苄好。实验还发现商陆抑菌活性最强的物质大都存在于根中,且抑菌活性最强的物质大都存在于水和正丁醇这种极性较高的溶剂的提取物中,不同提取物对不同细菌的抑菌活性情况不一致。因此本研究结果可以为商陆提取物抑菌性能的进一步探索提供参考。     

不同pH条件下添加纳米型蒙脱土和高岭土对溶液中铜的去除效果研究

通过有机插层法对蒙脱土、高岭土进行改性,制备成纳米型蒙脱土、高岭土,并利用制备的纳米型高岭土、蒙脱土对溶液中铜的吸附效果及吸附机理进行了研究。结果表明,纳米型蒙脱土和高岭土对溶液中的铜具有很好的去除效果,其吸附等温线可以用Langmuir和Freundlich方程进行拟合。相比而言,蒙脱土比高岭土具有较高的吸附量和吸附亲和力参数。在溶液中铜离子浓度低于120 mg/L时,纳米型蒙脱土、高岭土对铜的最大去除率分别达到99.5%和94.3%,对溶液中铜的去除率随铜离子浓度增加和溶液的pH降低而降低。     

中国农村生物质能利用技术和经济评价

农村生物质能利用技术种类较多,确定各类技术的适用范围及经济性,有利于在农村地区选择合适的技术,促进生物质能利用技术在农村的开发利用。该文提出了户均用能成本的概念和计算方法,对农村户用沼气、养殖场沼气工程、固体成型燃料、秸秆沼气、秸秆气化集中供气等技术进行了技术经济评价。研究结果表明:农村户用沼气技术的经济性最好,其次为固体成型燃料技术,而秸秆气化集中供气技术的经济性最差。随着农村社会经济的发展,认为固体成型燃料技术将逐渐占主导地位,而秸秆沼气技术可以填补由于畜禽粪便短缺而带来的空白。     

多尺度高分辨率全球土地覆被遥感产品相对一致性比较

国家及区域尺度的土地覆被信息对于解决环境演变、生物多样性保护、生态系统评价及环境建模等一系列问题起着至关重要的作用。该文从国家及区域尺度分别比较了当前全球2种最高分辨率的土地覆被遥感产品,以便解释两者在空间及专题上的一致性和异质性。结果表明,GLOBCOVER和MODIS2种产品在国家尺度上具有较好的一致性,但在区域尺度上仍有较明显的差异,特别是在中国东北和西南地区;2种产品在林地、灌木、耕地和草地间存在严重的混淆现象;总体精度和Kappa系数在全国尺度和区域尺度有着较大的差异,总体精度值从全国尺度的56.35%降为区域尺度的27.01%,Kappa系数值从全国尺度的47.09%降为区域尺度的16.57%。在全国尺度上东北区域有着最好的一致性,四川盆地的总体一致性最差;MODIS产品的类别均质性百分比明显优于GLOBCOVER,类别一致性百分比与空间一致性之间存在显著的相关性,其决定系数R2为0.724,说明产品间的类别均质性百分比差异越小,两者的空间一致性越高。该研究可为遥感产品的使用者提供准确可信的信息分布,为产品生产者有针对性改进分类算法提供科学合理依据。     

甘薯叶光合特性与块根主要性状对氮素供应形态的响应

为探明甘薯叶光合特性与块根主要性状对不同氮素形态供应的响应特点,以徐薯18为研究对象,在盆栽条件下,设置铵态氮、 硝态氮和酰胺态氮3种氮素处理,研究不同形态氮素供应对甘薯叶光合特性、 块根产量与品质性状影响的差异。结果表明,在移栽后30 d 和50 d 时,酰胺态氮处理叶片叶绿素含量(CCI)为最高,70 d时,铵态氮处理的CCI最高;铵态氮处理显著提高叶片的光合速率与有效辐射(PAR);氮素处理明显提高甘薯块根产量,其中,铵态氮处理较硝态氮和酰胺态氮处理块根产量分别增加10.6%与17.2%,增产显著(P0.05);铵态氮处理提高甘薯块根的淀粉率和蛋白质含量,而酰胺态氮处理增加可溶性糖和还原糖含量;铵态氮处理有利于增加甘薯淀粉最高粘度值（PKV）、 崩解值（BDV）和回复值（CSV）,而硝态氮处理促进最低粘度值（HPV）和最终粘度值（CPV）的上升。     

Distribution of carbon and nitrogen in water-stable aggregates and soil stability under long-term manure application in solonetzic soils of the Songnen plain,northeast China

Purpose

Excessive exchangeable sodium and high pH significantly decrease soil structural stability and permeability. Long-term application of cattle manure is an important management practice that can affect water-stable aggregates (WSAs), as well as aggregate stability and distribution of soil organic carbon (SOC) and total nitrogen (TN) in solonetzic soils.

Material and methods

Experiments were carried out in a randomized complete block design comprising five treatments according to the cattle manure application history: corn (Zea mays) with manure applied for 1, 5, 12, and 17 years were used as the experimental treatments and corn without manure application was used as a control. Soil properties, including WSAs, mean weight diameter (MWD), and SOC and TN concentrations in bulk soils and WSAs, were measured across all treatments. The relationships among the measured soil attributes were determined using stepwise regression analysis.

Results and discussion

Results indicated that micro-aggregates mainly accumulated in soils without manure application, while manure application significantly increased macro-aggregates formation. MWD was highest when manure was applied to the soil for 1 year, decreased after 5 years, and increased again after 12 years. SOC and TN concentrations in bulk soils and WSAs increased with the number of years of manure application, with the highest concentrations observed for 17 years in bulk soils. Stepwise regression analysis showed that WSAs 2–5 mm, SOC in WSAs 0.25–0.5 mm, and TN in WSAs 0.1–0.25 mm were dominant independent variables affecting aggregate stability, and that SOC in WSAs 0.25–0.5 mm and TN in WSAs <0.1 mm were dominant independent variables affecting SOC and TN concentrations in bulk soils, respectively.

Conclusions

Long-term application of manure to a solonetz significantly increased macro-aggregates and aggregate stability as well as SOC and TN in bulk soils and all aggregate sizes. These results are likely related to binding agent production as well as C and N accumulation from manure application.     

农作物空间格局变化模拟模型的MATLAB实现及应用

Agent模型是研究农业土地系统复杂性与动态性的有效工具。在农作物空间格局变化模拟模型(CroPaDy,an agent-based model for simulating crop pattern dynamics)概念化设计的基础上,借助MATLAB平台开放性、矩阵运算能力强等特点,实现CroPaDy模型的数值模拟,并以黑龙江省宾县调查数据为依据,完成模型的区域实证研究。基于MATLAB的模型实现过程充分考虑了CroPaDy模型的多层次性(土地流转行为与作物选择行为)成功实现了3个子模块的动态嵌套模拟:1)Agent生成模块。基于已有的多源GIS数据、统计数据、典型调查数据、以及个体的通用规则,利用蒙特卡洛方法生成每一个个体Agent的属性信息;2)Agent分类模块。基于调查数据对受访农户进行态度聚类分析,然后借助人工神经网络方法确定所有生成的Agent所在的类型;3)Agent决策模块。利用概率方法,计算特定周期内每个Agent的决策行为。区域实证研究中,直接将空间耕地网格作为个体Agent,实现区域全覆盖(网格大小设置为114 m×114 m,约等于户均耕地面积),模拟结果表明,研究区2010年玉米、大豆、水稻、烤烟的模拟结果分别为2 6055.9、5 192.2、3 506.8、3 983.9 hm2,利用宾县统计年鉴(2010)进行验证,模型总体模拟精度达90%以上。CroPaDy模型的设计与实现科学合理,具有较强的理论性与可操作性,能够用以表达特定区域内的农作物空间格局及其动态变化过程。     

基于电阻抗成像的植物单根断层图像重建

为了实现植物根系结构形态的原位检测,植物根系单根的断层图像重建研究非常必要。该文应用动态电阻抗成像技术对土壤-树根模拟系统进行了图像重建,对重建图像进行二值化处理并求出树根在该系统中的位置坐标、面积和形状,并以树根的位置坐标、面积及形状的相对偏差为指标,分析了图像重建算法、土壤含水率2个因素对成像质量的影响。结果表明：电阻抗成像技术能够实现树木单根断层图像重建;将重建图像进行二值化处理,所得图像更加直观,便于定量评价成像质量;基于Newton单步残差正则化的一步牛顿误差重构（Newton's one-step error reconsruction,NOSER）算法,比基于全变差正则化的主双-内点模式（primal dual-interior point method,PD-IPM）算法的成像质量好;土壤含水率越高成像质量越好。该研究为基于电阻抗成像技术的植物根系结构形态的图像重建提供参考。