Effects of Nitrogen Application Rate and Ratio on Lodging Resistance of Super Rice with Different Genotypes

The objective of this study was to determine the morphology mechanism of nitrogen （N） fertilizer rates and ratio on lodging resistance through analying its effects among lodging index （LI）, lodging-related morphological traits and physical strength in basal intemodes by comparing japonica and indica super rice cultivars. Field experiments, with three nitrogen levels （0, 150 and 300 kg ha-L） and two ratios of basal to topdressing （8：2 and 5：5） with two super rice cultivars （Yliangyou 2 and Wuyunjing 23）, were conducted in the Baolin Farm, Danyang Country, Jiangsu Province, China, in 2011 and 2012. Effects of N fertilizer rates and ratios on morphology of whole plant, morphology traits in basal intemodes and culm＇s physical strength parameters were investigated at 20 d after full heading stage. LI of Yliangyou 2 was significant greater than that of Wuyunjing 23 due to larger bending moment by whole plant （WP） with higher plant height and gravity center height. With higher volume of N fertilizer, LI of two super rice cultivars was increased conspicuously. However, no significant effect was detected with increase of panicle fertilizer ratio. The size of breaking strength （M） in basal intemodes was the key factor determining LI among N fertilizer treatments. Correlation analysis revealed that M value was positively related bending stress （BS） of Wuyunjing 23 and section modulus （Z） of Yliangyou 2, respectively. The higher N fertilizer levels induced reduction ofBS of Wuyunjing 23 due to weak culm and leaf sheath plumpness status and reduced Z of Yliangyou 2 owning to small diameter and culm wall thickness, consequently, influencing their M indirectly. These results suggested that breaking strength was the key factor influencing LI with increase of N fertilizer levels. However, the lodging-related morphology mechanism was different with genotypes. Culm wall thickness and diameter in basal internodes of indica super rice and culm and leaf sheath plumpness status of japonica super rice influenced breaking strength, as well as lodging index, respectively.     

海南沿海羊栖菜和海带不同提取物的抑菌活性

本实验以金黄色葡萄球菌(St aphyl occoccus aureaus Rosenbach)、大肠埃希菌(Escheri-chi a col i)2种需氧型细菌作为供试细菌,用圆形纸片法对羊栖菜和海带的无菌水、乙醚和乙醇提取物进行抑菌试验。结果表明:采用水提法、95%乙醇浸提取法和乙醚索氏提取法均能从羊栖菜和海带中提取出活性物质,提取回收率依次为水提法>乙醇提法>乙醚提法;比较对羊栖菜和海带3种不同提取方法得出:乙醇提取物对两种菌体的抑菌活性相对水提物和乙醚提取物较好,且乙醇提取物乙酸乙酯相对水相抑菌活性较好;比较羊栖菜和海带乙醇提取物乙酸乙酯相的MIC得出:海带对大肠埃希菌和金黄色葡萄球菌的MIC相对羊栖菜较低,抑菌效果较好。     

轮边液压驱动式麦弗逊悬架转向梯形设计

通过在多体动力学软件RecurDyn中建立采用轮边液压驱动的麦弗逊独立悬架模型,以转向梯形各球铰空间位置为设计变量,根据实车空间布置情况及轮边液压驱动式麦弗逊悬架布置特点确定优化参数范围。考虑汽车转向运动学及车轮跳动对转向影响,确定了优化目标函数,对车轮添加转向及跳动约束,对转向梯形断开点位置进行计算,使内外轮转向误差角较小、跳动转向角较小。     

Impact of high-fat and high-carbohydrate diets on liver metabolism studied in a rat model with a systems biology approach

The aim of the present study was to investigate the use of an integrated metabolomics and proteomics approach in the elucidation of diet-induced effects on hepatic metabolism in a rat model. Nuclear magnetic resonance (NMR)-based metabolomics of liver extracts revealed a pronounced effect of a high-fat diet on the hepatic betaine content, whereas a carbohydrate-rich diet induced increases in hepatic glucose. In addition, the metabolomic investigations revealed that the high-fat diet was associated with increased hepatic lipid levels, which was not evident with the carbohydrate-rich diet. The proteomic investigations revealed strong high-fat diet effects on the expression of 186 proteins in the liver including malate dehydrogenase. Comparison of malate dehydrogenase expression determined by proteomics and NMR metabolite profiles revealed correlations between malate dehydrogenase and lactate, glucose, and glutamine/glutamate signals, thereby demonstrating a diet-induced regulation that was evident at both proteomic and metabolomic levels.     

生草免耕桃园生态系统的碳交换动态变化特征

植物固碳是减缓全球气候变暖的有效途径。然而,农田尺度果园固碳能力目前还不清楚。该文采用涡度相关技术,研究粗砂土立地条件下12a生树龄生草免耕桃园生态系统碳交换和能量平衡各分量的动态变化。结果表明,在盛花期存在明显的固碳能力,日峰值为-0.33mg/(m2·s)(以CO2计)。在旺盛生长期波文比值在0.3以下,日净固碳值最高为-25.1g/(m2·d)(以CO2计)。落叶期存在明显的高CO2排放,日峰值为0.60mg/(m2·s)(以CO2计)。监测期内桃园生态系统日平均波文比值和净固碳量分别为(1.22±1.56)和(-2.90±6.63)g/(m2·d)(以CO2计),年净生态系统碳交换量(net ecosystem exchange,NEE)为-1052g/(m2·a)(以CO2计)。以上结果揭示粗砂土12a生树龄生草免耕桃园生态系统有较强的固碳能力。该文为评价果园碳汇功能提供基础数据。     

纵向载荷下作物茎秆"挠曲线"的变化特征测试与分析

摘要：以"非完善压杆"为作物茎秆的力学模型,应用力学理论,分析了纵向载荷下茎秆挠度与影响作物茎杆倒伏的各种因素间的关系。用简易测量装置对3个不同品种的小麦茎秆在不同纵向载荷下的"挠曲线"进行了测量。通过对相关测试数据的科学分析表明,作物茎秆"挠曲线"的形状变化是诸多因素作用的结果,"挠曲线"的坐标物理意义明晰、测量方便、操作简单,可用来评价作物抗倒性。并从理论和试验两方面证明了其评价作物抗倒性的合理性。该研究可为抗倒伏研究和相关农业机械的设计提供参考。     

基于模糊自适应纯追踪模型的农业机械路径跟踪方法

为了提高农业机械自动导航控制系统的精度,提出了一种基于模糊自适应纯追踪模型的农业机械路径跟踪方法.该方法基于纯追踪模型进行农业机械路径跟踪控制,结合农业机械运动学模型来确定车轮期望转向角;采用模糊自适应控制在线自适应地确定纯追踪模型中的前视距离,提高了路径跟踪的精度.农业机械的路径跟踪实验结果表明,路径跟踪的最大误差不超过10 cm,平均误差小于5 cm,完全满足农业机械的作业要求,验证了提出方法的可行性和有效性.     

韭菜等几种植物根系分泌物对棉花黄萎病菌的影响

通过水培法收集韭菜、大葱、野薄荷、藿香和薰衣草的根系分泌物,研究其对大丽轮枝菌菌丝生长、孢子萌发的影响,并通过室内盆栽试验研究了植物根系分泌物对大丽轮枝菌微菌核萌发的影响。结果表明,5种植物根系分泌物对大丽轮枝菌菌丝生长和孢子萌发均表现为抑制作用;随着浓度的升高,抑制作用增强,而在同一浓度下,随着处理时间的延长,根系分泌物对孢子萌发的抑制作用逐渐减弱。盆栽试验表明,植物根系分泌物对大丽轮枝菌微菌核的萌发均表现为抑制作用,且微菌核对韭菜根系分泌物最为敏感。5种植物中,韭菜根系分泌物的抑制作用最强,野薄荷次之,藿香最弱。     

甘肃省小麦条锈菌的潜育越冬研究

为系统了解小麦条锈菌在甘肃冬小麦种植区的越冬情况,2011-2013年采用冬前田间定点标记、冬后移栽至温室系统观察和条锈菌实时荧光定量PCR检测等方法,分析了甘肃省天水市秦州区、陇南市礼县和平凉市庄浪县小麦条锈病的越冬株率和越冬菌源量。结果表明,小麦条锈菌在天水、陇南和平凉地区均能顺利越冬,但三地间的越冬株率和越冬菌源量均存在着显著差异(P0.05);实时荧光定量PCR方法较直接观察法更为准确,可以用于小麦条锈菌的早期准确监测。     

陇南、陇东和关中地区小麦条锈病远程预警系统

为有效预测预报小麦条锈病,采用跨平台动态网页语言JAVA和数据库管理系统MySQL,以近30年积累资料构建的模型为基础,结合专家经验,建立了陇东、陇南和关中地区小麦条锈病远程预警系统(http://wrs.nwsuaf.edu.cn)。本系统由条锈病预测、信息管理、用户登录和后台管理4个模块组成,可以实现小麦条锈病流行程度的长、中、短期预测,以及病害造成的损失预测和病害防治的关键时期预测。利用平凉、天水和宝鸡2000-2013年间的相关资料对该系统进行了检验,其长、中、短期预测准确率分别为85.7%、92.6%和92.6%,可实现小麦条锈病准确远程预测和数据管理。