Non-target-site and target-site resistance to AHAS inhibitors in American sloughgrass (Beckmannia syzigachne)

American sloughgrass (Beckmannia syzigachne (Steud.) Fernald) is one of the most competitive and malignant weeds in rice-wheat rotation fields in China. American sloughgrass populations in the Jiangsu Province of China became less sensitive to acetohydroxyacid synthase (AHAS) inhibitors after repeated application for many years in these areas. Two suspected resistant American sloughgrass populations (R1 and R2) collected in the field were detected the resistance to inhibitors of AHAS in whole-plant dose-response assays, compared to the susceptible (S) population. These assays indicated that R1 showed low resistance to mesosulfuron-methyl (3.32-fold), imazapic (2.84-fold) and pyroxsulam (1.55-fold), moderate resistance to flazasulfuron (4.67-fold) and pyribenzoxim (7.41-fold), and high resistance to flucarbazone (11.73-fold). However, using a combination of the cytochrome P450 inhibitor, malathion, with mesosulfuron-methyl resulted in a reduction in R1 resistance relative to mesosulfuron-methyl alone. Furthermore, R2 was highly resistant to flazasulfuron (34.90-fold), imazapic (11.30-fold), flucarbazone (49.20-fold), pyribenzoxim (12.94-fold), moderately resistant to mesosulfuron-methyl (9.77-fold) and pyroxsulam (6.26-fold), and malathion had no effect on R2 resistance to mesosulfuron-methyl. The full-length of AHAS genes was sequenced and the AHAS enzymes were assayed in vitro in order to clarify the mechanism of resistance to AHAS inhibitors in R1 and R2 populations. The results demonstrated that R2 had a Pro-197-Ser mutation in the AHAS gene, and the sensitivity of R2 to the five AHAS inhibitors was decreased, which may result in R2 resistance to AHAS inhibitors. There was no mutation in the AHAS gene of R1, and there were no significant differences in enzyme sensitivity between susceptible (S) and resistant (R1) populations. An enhanced metabolism may be the main mechanism of R1 resistance to AHAS inhibitors.     

Effects of planting methods on yield and quality of different types of japonica rice in northern Jiangsu plain,China

Mechanical transplanting with carpet seedlings (MC) and mechanical direct seeding (MD) are newly developed planting methods, which increase in popularity and planted area each year. Knowing the difference for yield and rice quality under different planting methods is of great importance for the development of high quality and yield cultivation techniques under mechanical conditions. Therefore, three kinds of japonica rice including hybrid japonica rice, inbreed japonica rice, and soft rice were adopted as materials. And the differences in the quality of processing, appearance, cooking and eating quality, nutrition, and the rapid viscosity analyzer (RVA) profile were studied to reveal the effects of planting methods on yield and quality of different types of japonica rice. Results showed that the milled rice and head rice rates under MC was significantly higher than those under MD, and the processing quality of inbreed japonica rice was the most stable. Compared with MC, length/width ratio of rice under MD was significantly increased, and chalkiness rate, size, and degree were significantly decreased. The protein content under MD was lower than that under MC. MC showed higher peak viscosity and breakdown value than MD. The taste value was the greatest for soft rice, followed by inbreed japonica rice, and then by japonica hybrid rice, with no significant differences resulting from planting methods. Compared with MC, MD significantly improved the appearance quality, though processing quality and nutritional quality were decreased. And there was no significant difference in cooking and eating quality between MC and MD. Under different planting methods, the appearance quality of inbreed japonica rice changed the most and the processing quality was the most stable. The nutritional, cooking and eating quality of soft rice changed the least. Therefore, according to the different planting methods and market needs, selecting the appropriate rice varieties can reduce the risks in rice production and achieve good rice quality.     

高校图书馆开展“阅读优质服务月”活动的实践与思考

在“世界读书日”之际,我校图书馆为了“营造校园阅读氛围,延伸图书馆的服务功能”,开展了以“书籍滋养心灵,阅读充实人生”为主题的阅读优质服务月活动,活动内容丰富,活动效果受到读者的广泛欢迎,总结活动规律,将会为今后开展此类活动留下宝贵的经验。     

福建红芽姜漳州平原地区有机栽培技术

根据有机产品国家标准的要求,利用漳州市香蕉园及苦瓜棚下进行红芽姜的立体套种模式,并总结‘科姜1号’的有机栽培技术。     

对投资决策假设的思考

项目投资决策是企业财务管理的重要环节,投资者通过运用资本预算方法,对项目的财务可行性进行分析,进而做出决策。在这些资本预算方法中,往往内涵了很多前提和假设,合理的假设可以简化计算和分析过程,是投资决策中必不可少的。但是在投资实务中,有很多与理论相矛盾的问题,这与资本预算方法假设的合理性存在不可忽视的关联。将选取几个较为常见的投资决策的假设,对其现实性、合理性做出探讨,旨在更好的为投资决策服务。     

12个茶树菇菌株鉴定及农艺性状分析

为区分和筛选性状优良的茶树菇(Agrocybe aegerita)菌株,对12个不同来源的菌株进行了拮抗检测和农艺性状比较分析。结果表明,12个菌株被归为5组,1号、4号、6号、8号和9号菌株的菌丝长势强,生长速度快,生物学效率均在86%以上,综合性状优良。其中1号和8号菌株的子实体生长适宜温度相对较高,可选择在夏秋季栽培,4号菌株子实体生长适宜温度相对较低,可选择在春季栽培。     

A method for raising brown planthopper (BPH), Nilaparvata lugens (Stal)

To get mass population of the BPH, a good method for raising BPH is needed. In this paper, a convenient method was recommended.     

玉米抗大斑病相关基因片段的表达研究

以玉米自交系B37Htl与玉米大斑病菌0号小种和1号小种构成非亲和性互作和亲和性互作体系,利用mRNA差异显示(DDRT-PCR)技术研究了互作过程中玉米叶片基因表达的情况.结果表明,非亲和性互作中特有的表达片段7条,较亲和性互作及对照表达明显增强的片段21条,表达明显减弱的18条.对非亲和性互作中特有的表达片段进行克隆、测序及同源性分析,发现它们与已知抗病基因没有同源性.